Science for South Africa
Volume 2 • Number 4 • 2006 R20 incl. VAt
Academy of Science of South Africa
Discovering our biodiversity Members of the South African Biosystematics Initiative Getting to know the living species of South Africa 7
■ What’s new? The web of life investigated Really early birds, Tim Crowe • Geology and climate play their part, Nigel Barker • A land snail riddle solved, Dai Herbert • Small mammal biodiversity matters, Chris Chimimba • Knowing and saving our millipedes, Michelle Hamer
Contents VOLUME 2 • NUMBER 4 • 2006
A new football for South Africa Jos Lurie A super-symmetrical ball for a winning nation
Fact file What do we know? South Africa’s flora, fauna, and microbiota
The six-legged flying squad
The sexes are different; Scorpions help fight cancer (p. 27) • Day flights to reduce climate warming (p. 39) • Don’t interrupt; How researchers spend their time; Switch off in a storm; Perilous overconfidence (p. 45)
Martin Villet and Nikite Muller Forensic work with bugs and insects
Finding extrasolar planets
Careers Careers in systematics (p. 11) • Work in forensic entomology (p. 27)
Viewpoint Vision of quality education for all
John Menzies Microlensing and the search for distant planets
Benito Khotseng 36
The S&T tourist Rocks, mines, and daisies Sandy Ferrar Visit Barberton for the oldest signs of life, the gold rush, and South Africa’s most famous daisy
Low-smoke fires are best
Marlett Balmer How to cut pollution from household fires
No alcohol if you’re pregnant! Lillian Ouko and Michèle Ramsay Fetal Alcohol Spectrum Disorder is preventable
Where river meets ocean Paul Vorwerk and William Froneman Abundant wealth from estuaries
Your QUESTions answered Is solar energy really a feasible solution? – Chris Engelbrecht
Books François Levaillant and the Birds of Africa Reviewed by Alan Kemp • Karoo Veld: Ecology and Management (p. 42) • and other titles
Letters to QUEST Creative science
Diary of events
Subscription form • Back page science
Pictured above: Lutjanus kasmira (bluebanded snapper) found on coral and rocky reefs. Photograph: Paul Leroy
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Method is the key
A mushroom soft coral, Alcyonium variabile (Thomson, 1921), one of South Africa's many endemic marine animals, ranging from Cape Town to southern Zululand at depths of 15–450 m. Photograph: Dai Herbert
SCIENCE FOR SOUTH AFRICA
Editor Elisabeth Lickindorf Editorial Board Wieland Gevers (University of Cape Town) (Chair) Graham Baker (South African Journal of Science) Anusuya Chinsamy-Turan (University of Cape Town) George Ellis (University of Cape Town) Jonathan Jansen (University of Pretoria) Colin Johnson (Rhodes University) Correspondence and The Editor enquiries PO Box 1011, Melville 2109 South Africa Tel./fax: (011) 673 3683 e-mail: firstname.lastname@example.org (For more information visit www.assaf.co.za) Business Manager Neville Pritchard Advertising and Neville Pritchard subscription enquiries PO Box 130614 Bryanston 2074 South Africa Tel.: (011) 781 8388 Fax: (011) 673 3683 Cell: 083 408 3286 e-mail: email@example.com Copyright © 2006 Academy of Science of South Africa
uch of science has to do with finding gaps, then finding ways to fill them. A theory can set the ball rolling, then someone applies method to uncover evidence that proves or disproves it. Facts emerge, pointing to constructive, often unexpected uses. The process brings huge benefits to society. This issue of QUEST celebrates all kinds of method. Biosciences Month this August brings a cover picture of the extraordinary richness and beauty of marine animals, and the systematists’ stories of discovering and recording details of southern Africa’s biodiversity are rooted in the power of method (p. 3). South Africa is the world’s third most biologically diverse country and home to between a quarter of a million and a million living species large and small, but half or more of them, we’re told, are still unknown to science. Without the crucial groundwork of taxonomists in identifying species and phylogeneticists in working out evolutionary relationships, we’d never know what species are around for us to enjoy, conserve, or put to productive use. On the scale of the Universe, another gap is being filled (p. 30). With the help of new technology, astronomers have devised methods – deriving from Einstein’s Theory of General Relativity – for finding planets that orbit stars other than our Sun. Now South Africans have helped to find the lowest-mass extrasolar planet yet discovered. Closer to home, scientific method in action reveals that some populations in the Cape are genetically more at risk of contracting Fetal Alcohol Spectrum Disorder than other people (p. 16). It’s known that alcohol consumed by expectant mothers can have a detrimental effect on their babies, but knowing who is genetically most vulnerable allows better preventative methods to be designed so that entire groups of children can be protected from contracting this incurable medical condition. Being rigorously methodical is practical. Applying the mathematics of symmetry and sphericity could help with the design of a 2010 South African World Cup football that’s better than any other (p. 12). Entomologists recording the life cycles of bugs and insects help forensic investigators to solve disputes and police to solve crimes such as murder (p. 24). Comparing zooplankton populations in the ocean opposite river mouths with those further out at sea can help us to understand how fertile estuaries really are (p. 21). And building coal and wood fires in the right way can reduce air pollution and help people to avoid respiratory diseases that kill 2 000 South African children a year (p. 11). Method helps researchers to answer their own questions, and it translates into answers for the issues that societies have to contend with. Viva method! it’s ‘win-win’ for everyone.
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Elisabeth Lickindorf Editor – QUEST: Science for South Africa Join QUEST’s knowledge sharing activities Write letters for our regular Letters column – e-mail or fax your letter to The Editor and win a prize. (Write QUEST LETTER in the subject line.) ■ Ask science and technology (S&T) questions for specialist members of the Academy of Science to answer in our regular S&T Questions and Answers column – e-mail or fax your questions to The Editor and win a prize. (Write S&T QUESTION in the subject line.) ■ Inform readers in our regular Diary of Events column about S&T events that you may be organizing. (Write QUEST DIARY clearly on your e-mail or fax and provide full and accurate details.) ■ Contribute if you are a specialist with research to report. Ask the Editor for a copy of QUEST’s Call for Contributions (or find it at www.assaf.co.za), and make arrangements to tell us your story. To contact the Editor, send an e-mail to: firstname.lastname@example.org or fax your communication to (011) 673 3683. Please give your full name and contact details. ■
Discovering our biodiversity
Members of the South African Biosystematics Initiative explain what scientists do to catalogue and record the many forms of life on Earth – and why and how they need to do it.
Discovering our biodiversity S
outh Africa has an astonishingly rich biota of plant, animal, and microbial life. Home to between 250 000 and 1 million living species (we have no accurate idea of the number), it is the world’s third most biologically diverse country. But, alarmingly, it has been estimated that at least half (but maybe much more) of the country’s biodiversity remains undiscovered, especially among invertebrates1. We still have to establish its true extent as well as its importance to human welfare and the welfare of other living creatures. How do we tap this wealth? First, by getting to know what we have; second, by understanding what it does and can do for the region and its people; third, by looking after it in the right way.
Global action At the 1992 Earth Summit in Rio de Janeiro, the United Nations Conference on Environment and Development (UNCED) highlighted the world’s looming biodiversity crisis and the need for continued economic growth that, simultaneously, maintains the integrity of the biosphere. Its global action plan, Agenda 21, called for increased knowledge about the Earth’s biodiversity. The International Convention on the Conservation of Biological Diversity (CBD) was adopted, whose three objectives are: the conservation of biological Above: A pair of Pseudocreobotra wahlbergi (flower mantids) mating on flowers of Helichrysum areum. Photograph: John Leroy.
Clockwise (from top left): Xanthus maculatus (Sakai, 1961), a small bizarrely coloured crab previously known only from Japan, but recorded for the first time in South Africa in 1996, living off northern Zululand. Photograph: Dai Herbert • Suricata suricatta (meerkat or suricate), an open arid-country endemic to southern Africa. Photograph: John Leroy • Epinephelus fasciatus (redbarred rockcod). A species common to coral reefs. Photograph: Paul Leroy • Coriolopsis polyzona (bracket fungus). Photograph: John Leroy • Hyperolius marmoratus (painted reed frog). Photograph: John Leroy • Papilio demodocus (swallowtail butterfly), widespread and common in our region. Photograph: John Leroy 1. An invertebrate is an animal without a backbone.
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Definitions ■ Biodiversity (biological diversity): the totality of the various living organisms, the genetic differences among them, and the communities and ecosystems in which they occur. It is the ‘natural wealth’ of the Earth, supplying all our food and much of our shelter and raw materials. ■ Biota: the combined plant, animal, and microbial life of a particular region or period. ■ Systematics: a broad term for the scientific study of the diversity of organisms and their natural relationships. The term biosystematics describes the experimental study of diversity, especially at the species level. ■ Taxonomy*: the science of discovering, identifying, naming, and documenting all the life-forms making up the Earth’s biological diversity. It provides the core reference system for all scientific endeavour in the biological sciences. Taxonomists document, understand, and disseminate knowledge about the Earth’s estimated 10 millionplus species, and provide the scientific foundation for conservation and sustainable use of biodiversity. ■ Phylogenetics focuses on the understanding of evolutionary genealogical relationships among organisms, species, higher taxa, and other biological entities such as genes. Amongst other things, it develops methods for phylogenetic inference and a biological nomenclature/classification. (Cladistics is concerned with the branching order; phylogeny, in addition, is concerned with the lengths of the branches of the phylogenetic tree.) * The term ‘taxonomy’ erives from the Greek taxis (‘arrangement’) and nomos (‘law’), and indicates the methodologyand principles of systematic botany and zoology. ‘Taxa’ are taxonomic categories.
From top: Undescribed species of Trachycystis (pinwheel snail) recently discovered in the coastal forests of the Transkei region. Photograph: Dai Herbert • Homopus bergeri (Nama padloper), a very small tortoise endemic to the arid western parts of South Africa. Photograph: John Leroy • Opisthopatus herberti (velvet worm). Described in 2005 and named after Dai Herbert, who was the first person to collect the species and recognize its importance. Velvet worms have been called the missing link between insects and earthworms; they are also regarded as living fossils as they have changed little over some 500 million years. Photograph: Hilke Ruhberg • Palystes sp. (rain spider), a large spider endemic to Africa that enters houses before and during rainy spells. Photograph: Les Oates • Kniphofia coddiana grows to a height of 0.5–0.65 m at an altitude of 60–500 m and possibly endemic to KwaZulu-Natal and the Eastern Cape. Photograph: Von Fintel. Courtesy of SANBI
diversity; the sustainable use of its components; and the equitable sharing of the benefits arising out of the use of genetic resources. To achieve specific global scientific objectives, the systematics biologists further proposed Systematics Agenda 2000, agreeing upon an intensive international effort with three interrelated missions: to discover, describe, and make an inventory of the world’s species (a Catalogue of Life); to analyse and synthesize the information into predictive classification systems that reflect the evolutionary history of life; and to organize the information in an efficient and retrievable form. Recognizing the ecological services, economic potential, and spiritual benefits that biodiversity provides, South Africa signed the CBD and, in 2004, introduced changes in national legislation that have important consequences for everyone connected with biodiversity research and conservation2. Taxonomy and phylogeny To protect and make sustainable use of any living species, we must know what species we have. The science that covers this area is called systematics, within which taxonomists and phylogeneticists work. Taxonomists discover, describe, and name individual species of animals, plants, and microbes. Their research yields species descriptions, revisions, inventories, identification keys, field-guides, detailed monographs, regional floras and faunas, and Red Data lists.
How scientific naming works Every species of organism known – living or extinct – has a scientific name. The father of scientific nomenclature was the Swedish botanist, Carolus Linnaeus* (1707–1778). He created the naming system, still used today, in which every species is given two Latin names, a genus or group name (plural ‘genera’) and the species name. Being ‘foreign’ words, they are italicized. Many closely related species may share the same genus name but, within the same genus, each species name is unique. The same genus name cannot be used for any plants or animals that are not closely related. Thus the full scientific name – genus and species – is always different for every species. For example, ‘Homo’ is a genus name, ‘sapiens’ is the species name, and ‘Homo sapiens’ is the full, unique scientific name. This form of nomenclature is also called the Binomial System of Nomenclature. Species are the basic unit of biodiversity and the name correctly assigned to a species is the key to all the existing knowledge about that species. Linked to its unique name is information about the specific organism (such as morphology, distribution, behaviour, and much else).
The Linnaean system The Linnaean system groups organisms into a hierarchical classification system using seven major divisions or ‘higher taxa’. These divisions are: ● Kingdom ✦ Phylum ■ Class ● Order ✦ Family ■ Genus ● Species The classification tells us something about the degree of relationship between different organisms. * His Swedish name was Carl von Linné.
Building on taxonomy is the science of phylogenetics, which aims to establish the evolutionary genealogical relationships among taxa and to produce predictive classifications and phylogenies (or evolutionary sequences) that reflect these relationships. It provides a conceptual framework for organizing and interpreting biological information. Research in taxonomy and phylogenetics serves national priorities in providing the essential platform for exploring South Africa’s
2. Two main developments were the passing of the National Environmental Management: Biodiversity Act (No. 10 of 2004) and the creation of the South African National Biodiversity Institute (SANBI).
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Discovering our biodiversity
Q Fact file Helichrysum adenocarpum grows to a height of 0.1–0.45 m at an altitude of 15–3 050 m in Limpopo, North West, Gauteng, Mpumalanga, Swaziland, KwaZuluNatal, and Lesotho. Photograph: M. Koekemoer Courtesy of SANBI
What do we know?
* The Palaeotropical (or Afro-Tethyan) realm has two clear regions, which are sometimes regarded as separate. The Afrotropical region includes continental Africa south of the Sahara and southwestern Arabia (the South African sections are located in KwaZulu-Natal, Mpumalanga, and the Northern Province). The Oriental region includes tropical southern and southeastern Asia, with associated continental islands. The Cape Floristic Region hotspot, with an area of 78 555 km2, hugs the coastline along the far southwestern tip of the African continent and is located entirely within South Africa’s borders. One of the world’s five temperate Mediterranean-type systems on the hotspots list, it is one of only two hotspots that encompass an entire floral kingdom (the other being New Caledonia).
biological resources for sustainable use and economic growth. Responding to threats Ours is the first generation to recognize the huge threat facing millions of the species on Earth – and may well be the last with the opportunity to describe and record many of the undiscovered ones. We have a good picture of South Africa’s vertebrate fauna, but we certainly underestimate the extent of the country’s overall biodiversity. For invertebrate animals, fungi, and microbes the situation is even worse – only about one third to one half of our insect and mite fauna and less than 5% of our fungi have been described. What potential and opportunities remain hidden by our lack of knowledge? Many animal, plant, and microbial species in South Africa face possible extinction due to habitat loss as agriculture, mining, industry, and urbanization grow. The 1997 IUCN Red List of Threatened Plants lists 2 652 plant species as ‘threatened’ in the 10 countries of our region. In terms of area and in an absolute sense, southern Africa has the highest concentration of threatened plant taxa in the world. A great problem in documenting South Africa’s biodiversity is the chronically deficient support and funding for systematics, and staff reductions will seriously affect our ability to conserve our rich biological heritage, to understand and benefit sustainably from the ecological services it provides, and to maximize its potential to benefit humanity. The recovery and future progress of the sector in South Africa is itself under serious threat. In 2002, the national South African Biosystematics Initiative (SABI) was launched to try to increase the country’s ability to conduct research
South African systematists have contributed greatly to our knowledge of the nation’s flora, fauna, and microbiota and have helped to bring them to the world’s attention. They’ve shown, for example, that: ■ South Africa’s temperate flora is the richest on the planet, with 18 000 plant species; it is represented by two floristic kingdoms, the Palaeotropical and the Cape Floristic Region*. ■ 11 plant families are endemic to southern Africa, as well as 80% of the species and 29% of the genera of the region’s flora. ■ Of the global fauna, South Africa is home to 6.1% (241) of mammal species, 7% (800) of bird species, 4.6% (498) of reptile species, 15% (2 200) of marine fish species, 5.5% (43 565) of recorded insect species, and 7% (2 000) of recorded spiders. ■ There are over 8 800 marine invertebrate species along the coast, of which 36% are endemic to South Africa. Of the approximately 80 000 terrestrial invertebrates recorded here, about 50% of the species are endemic. In some groups (such as scorpions, earthworms, millipedes, and land snails), 80–100% of the species occur only in this country. ■ Microbes (including fungi, bacteria, and viruses) are among the most diverse and plentiful organisms in many parts of the world, yet we know very little about microbiota found in South Africa, apart from those causing diseases of animals and betterstudied agricultural crops. In the fynbos biome, it was found that less than 5% of fungi collected had previously been described. The same is probably true for most ecosystems in South Africa. ■ Information about our biodiversity is housed in South Africa’s natural history museums, science councils, gene banks, molecular laboratories, and botanical herbaria. Their collections are a priceless, irreplaceable biodiversity archive and resource, recording the nation’s biological heritage as a reference and research facility for scientists from around the world. These institutions also provide expertise in the taxonomy and systematics of much of Africa’s flora, fauna, and microbiota. ■ Much remains to be done, and the daunting size of the task is compounded by the extent of our great biodiversity.
From top: Lophyra fasiculicornis (tiger beetle). Photograph: Marion Burger. Transvaal Museum collection • Alcedo cristata (malachite kingfisher), commonly found near water. Photograph: John Leroy • Chamaeleo namaquensis (Nama chameleon). This big, aggressive, mainly terrestrial chameleon takes prey up to the size of a horned adder. Photograph: John Leroy
Visit the collections South Africa has many biodiversity collections. The research collections are not normally on view to the public, but many institutions provide guided tours for school or university groups on request. You’ll find natural history museums in Pretoria (Northern Flagship Institution, Transvaal Museum), Bloemfontein (National Museum), Pietermaritzburg (Natal Museum), Durban (Durban Natural Science Museum), East London (East London Museum), Port Elizabeth (Port Elizabeth Museum), Kimberley (McGregor Museum), Grahamstown (Albany Museum), King William’s Town (Amatola Museum), and Cape Town (Iziko Museums). In addition, the South African Aquatic Biodiversity Institute (Grahamstown) and the Agricultural Research Council, Plant Protection Research Institute, Biosystematics Division (Pretoria) also house collections of animals and microbes. There are national herbaria in Pretoria, Cape Town, and Durban, but many of the universities also have large herbaria (such as the University of KwaZulu-Natal in Pietermaritzburg, the University of Cape Town, Stellenbosch University, and the University of the Witwatersrand).
Become a volunteer Most museums and institutions offer opportunities for voluntary work (for example, the research section at Kirstenbosch Gardens and the Durban Natural Science Museum). For information, visit the South African National Biodiversity Institute website (www.sanbi.org) and the Durban Museum website (www.durban.gov.za/eThekwini/Tourism_and_Leisure/museums/ns).
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Discovering our biodiversity The South African Biosystematics Initiative (SABI) After South African systematists raised the alarm about the potential crisis in their field in terms of capacity and resources for research, the South African Biosystematics Initiative (SABI) was established in 2002* to provide a framework and strategy for: addressing dwindling national capacity in systematics; providing the leadership and coordination to promote innovative research in the field; empowering South African systematists to employ and develop modern scientific technologies and approaches with regard to the documentation and use of biological resources; improving the ability of South African systematics to contribute to the National System of Innovation and the information society, and thus to respond to national priorities in agriculture, health, sustainable development, and conservation; assisting the broader scientific community and government in fulfilling national and global biodiversity-related commitments; and promoting awareness of the importance of systematics research through education and outreach. SABI’s vision is to develop a representative community of systematics biologists, well-supported by government and society, to address issues relating to South Africa’s rich biological heritage. For more about SABI, visit the NRF website at www.nrf.ac.za. * SABI is managed and administered through the National Research Foundation and funded by the Department of Science and Technology. Through SABI, funding for systematics research is made available as well as bursaries for postgraduate study.
in biosystematics. Its vision is to rejuvenate the discipline, and to position it strategically so that biosystematics can play its full role as a crucial fundamental science, working on resources of inestimable value to the nation and the world. These initiatives need all the support they can get. ■ This feature was written by the following members of SABI: Professor Michelle Hamer (University of KwaZulu-Natal, Pietermaritzburg; also president of the South African Society for Systematic Biology and chair of the SABI Steering Committee), Professor Ansie Dippenaar-Schoeman (Agricultural Research Council), Dr Dai Herbert (Natal Museum), Professor Tim Crowe (University of Cape Town), Professor Gideon Smith (South African National Biodiversity Institute), Professors Mervin Mansell and Clark Scholtz (Department of Zoology and Entomology, University of Pretoria), Johan Pauw (Head of SAEON [South African Environmental Observation Network], National Research Foundation), and Professor Albert van Jaarsveld (Dean: Faculty of Science, University of Stellenbosch).
Top: Dromica sp. (tiger beetle). Photograph: Marion Burger. Transvaal Museum collection
Below: Parabuthus granulatus (granulated thick-tailed scorpion). Regarded as the most venomous scorpion found in South Africa, it has caused the deaths of several children. It is endemic to southern Africa. Photograph: Les Oates For more on the diversity of organisms on Earth, their evolutionary history, and their characteristics, visit the Tree of Life website at www.tolweb.org. Other useful sites include London’s Natural History Museum at www.nhm.ac.uk/ research-curation/index.html; the Iziko Museum at www.museums.org.za/biol/ (for the biodiversity explorer); the South African Reptile Conservation Assessment site at www.saherps.net/sarca (part of a project involving taxonomists – but anyone can contribute to documenting the South African reptile fauna and its distribution by providing researchers with information); the South African Biodiversity Information Facility (SABIF) at www.sabif.ac.za (with information on a large project that aims to coordinate and make available millions of records of species in South Africa, and housing documents and a database called “South African Biosystematics: State of Nature Study”, which is a recent audit of capacity, research, and training in systematics; collections and institutions; and the biodiversity of South Africa); the South African Institute for Aquatic Biodiversity at www.jlbsmith.ru.ac.za; the South African National Biodiversity Institute at www.sanbi.org (with links to various projects on South African biodiversity and information on the national herbaria and botanical gardens); and the Agricultural Research Council, Plant Protection Research Institute at www.arc-ppri.agric.za (where many taxonomists conduct research on different groups of organisms).
What’s new? South African systematists describe some of their findings. Really early birds Tim Crowe, University of Cape Town
Evolutionary and biogeographical relationships among gamebirds. A. megapodes; B. cracids; C. guineafowls; D. stone partridges; E. New World quails; F. Udzungwa partridge; G. hill partridge; H. peafowls; I. pheasants; J. grouse; K. African peacock; d = dispersal event; f = fossil site. Bird illustrations courtesy J. del Hoyo, A. Elliott, and J. Sargatal, (eds), Handbook of the Birds of the World. Volume 2. New World Vultures to Guineafowls. (Lynx Edicions, Barcelona, 1994).
and that gamebirds originated in Asia. Theses conclusions also suggest that Gondwana’s breakup influenced gamebird evolution. ▲ ▲
Systematics – the branch of biology that characterizes biodiversity – comprises three activities: taxonomy, phylogenetics, and biogeography1. Our team of systematists has recently completed a study of the phylogenetics and biogeography of gamebirds, chicken-like birds in the avian order Galliformes. Using fossil, anatomical, behavioural, and molecular information, we found that gamebirds originated in Gondwana, the ancient supercontinent that, nearly 100 million years (Myr) ago, included what is now Africa, South America, Australia, and India. These conclusions challenge the current view that most modern orders of birds evolved less than 65 Myr ago (when the Earth was struck by a meteor that caused the extinction of dinosaurs)
1. Taxonomy involves discovering species, giving them scientific names, and classifying them in a way that reflects their phylogenetic relationships. Phylogenetics involves placing them onto the tree of life that represents their evolutionary genealogical relationships. Biogeography involves the discovery and explanation of patterns of the geographic distribution of species and their diversity.
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■ DNA evidence links the African stone partridges, Ptilopachus species, the New World quails, the Udzungwa partridge Xenoperdix udzungwensis (confined to two mountains in southern Tanzania), and the Asiatic hill partridge. ■ DNA and fossil evidence suggest that the Congo peacock Afropavo congensis, confined to primary rainforest in the eastern Democratic Republic of Congo, is a species derived from Asiatic peacocks.
Geology and climate play their part Nigel Barker, Rhodes University
Courtesy of Dr Krystal Tolley, SANBI, Kirstenbosch Research Centre
Right: Leucadendron argenteum, whose ancestors probably dispersed across the ocean to Africa from Australia.
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Above: The Transvaal dwarf chameleon (Bradypodion transvaalense) is just one example of South Africa’s many different types of chameleon. Dwarf chameleons are endemic to the country, and most species have a limited distribution. Although chameleons might be considered to be a familiar group of reptiles, DNA studies conducted at the South African National Biodiversity Institute are even now uncovering new species, a tell-tale sign of the remarkable biodiversity in this group.
The most ancient branch of the gamebird evolutionary tree resulted from Australia’s breakaway from the rest of Gondwana, leading to the evolution of megapodes, which are gamebirds with big feet that lay their eggs in pits either dug in volcanic soil or filled with compost heaps to provide the heat necessary for incubation. The next most ancient branch resulted from the breakaway of South America and led to the evolution of cracids, nearly all species of which are confined to that continent. Next come guineafowls, the characteristic African gamebirds. After that, things get more complicated, with Africa playing a key role. About 55 Myr ago, two major dispersal events of gamebirds out of Africa occurred. One – through present-day northwestern Africa, the Iberian Peninsula, Britain, and Greenland to North America – led to the evolution of New World quails. This was possible because the North Atlantic Ocean did not yet exist and there were continuous land bridges between present-day Europe and North America. The other dispersal event – through northeastern Africa and the Middle East into Asia – led to the evolution of pheasants, peacocks, grouse, and various partridge-like gamebirds. Next came a third dispersal event, about 35 Myr ago, this time from Asia back to Africa. How do we know that these dispersal events took place? This is where fossil and DNA evidence kick in. ■ Fossils from western Europe and North America place gamebirds (intermediate in form between guineafowls and New World quails) at around 55 Myr ago.
The range of life around us today is no accident but, rather, a consequence of past geological and climatological events acting together with evolutionary processes at the population level. Through molecular systematics we understand more about these past events in southern Africa. The amazingly diverse and highly restricted (endemic) plants of the fynbos, for example, probably resulted from climate changes that occurred 7–5 Myr ago. Further north in Africa, the weird, wonderful giant Lobelias and senecios (the genus Dendrosenecio) adapted to life at high altitude and extreme cold following the creation of the volcanic East African mountains such as Kilimanjaro about 3 Myr ago. Similarly, marine environments have experienced temperature fluctuations and changes in sea levels and currents, which have influenced coastal and marine organisms by changing the range of available niches as well as the distance and speed with which larvae, drifting in the currents, can get carried and established. These past events leave a ‘signature’ in the DNA of individuals and populations of species and, for older events, can be seen in the relationships
Discovering our biodiversity among genera, families, and even higher taxa. DNA studies conducted by our team on both plant and marine animal groups have indicated surprisingly high amounts of genetic diversity within species, signalling the effects of events of a more recent past. Plant studies on land, for instance, suggest that some species spread out of areas that had been refugia2 during the last ice age (about 13 000 years ago). Going further back, studies on plant groups distributed over the continents that were once part of the supercontinent of Gondwana reveal additional secrets about when such plants arrived where they did, and DNA data in conjunction with the fossil record indicate the ages of different lineages. Older groups, such as the Proteaceae, for example, were present on Gondwana, and many groups found today in South America, Africa, Australia, and New Zealand are remnants of widespread Gondwanan distribution. But we’ve now discovered that other genera in the same family are too recent to have been dispersed by the break-up of the supercontinent. Unlikely though it may superficially appear, they seem, in fact, to have travelled great distances across the oceans.
A land snail riddle solved Dai Herbert, Natal Museum and the University of KwaZulu-Natal
Photograph: Dai Herbert
Small mammal biodiversity matters Chris Chimimba, University of Pretoria Recent studies in southern Africa have revealed ‘cryptic’ small mammals that were previously unknown to science as different species because they were morphologically so like one another. But they are cytogenetically5 diverse, which suggests a need for a more fundamental understanding of their boundaries. We are investigating this largely undocumented biodiversity particularly in murid rodents (that is, rodents in the Muridae family), and our research affects work associated with problem rodents implicated in the epidemiology of bubonic plague, Rift Valley Fever, schistosomiasis, leptospirosis, taxoplasmosis, and in causing extensive damage to agricultural products. Investigations into the different species of murid rodents are useful in pest management, and critical for decision-making on the part of health and agricultural authorities. Our work, designed to serve as a model for application elsewhere in Africa and beyond, may also contribute towards the theoretical understanding of speciation in southern African small mammals,
Above: The Namaqua rock mouse, Aethomys namaquensis, a widely distributed species in southern Africa, is one of the species that is being studied to gain an insight into the radiation (or dispersal) of southern African rodents of the Muridae family and their evolutionary relationships.
For decades, the enigmatic genus Prestonella has perplexed scientists studying the land snail fauna of southern Africa, as nobody could establish with any certainty the family to which it belongs. The reason is simple: its shell has few characteristic features and its internal anatomy, which provides the most reliable data for determining family relationships in snails, was unknown. No living specimens of any of the three described species of the genus had been collected for over 50 years. To solve the Prestonella riddle, we had to find living specimens and study their anatomy. So Mary Bursey (of the East London Museum) and I took off for the Somerset East and Cradock areas in the Eastern Cape to find live examples of Prestonella at localities where the original specimens had been collected in the late 1800s. At Somerset East we discovered a colony of living Prestonella bowkeri in the gorge of Glen Avon falls and, near Cradock, specimens of P. nuptialis on the Elandsberg Mountain. Both species seemed to be habitat specialists, occurring only on bare rock faces within a limited area, in places associated with waterfalls (in the case of P. bowkeri), and the summits of Karoo inselbergs (in the case of P. nuptialis), along the southern edge of the Great Escarpment. In these cool, relatively moist environments amidst an otherwise dry region, the snails evidently feed on the microscopic algae growing on the rock. We then studied our specimens, using methods including micro-dissection, scanning electron microscopy, and DNA sequencing. The results were astonishing! Comparative analysis of the morphology3 of the embryonic shell, radula4, and reproductive tract, as well as DNA sequence data showed conclusively that Prestonella belongs to the family Bulimulidae.
Above: Prestonella nuptialis (Melvill and Ponsonby, 1894), a relict species reflecting South Africa’s Gondwanan past, still surviving in isolated colonies near the summit of ‘koppies’ in the Nama Karoo. Shell length: 12.8 mm.
Why was this so surprising? Because the family was hitherto unknown on our continent. Considered of Gondwanan origin, it is most diverse in South America, with representatives also in Australasia, but none had ever been described in Africa. Now we know that our seemingly unprepossessing Prestonella species descend from an ancient lineage of snails that became isolated from their relatives at least 90 Myr ago, when Africa separated from South America during the break-up of Gondwana. They cling on tenuously, in specialized habitats, as remnants of the supercontinent, and we need to conserve them carefully for their significant contribution to the phylogenetic diversity of the southern African fauna.
2. A refugium is an area in which a population of organisms can survive through a period of unfavourable conditions, especially glaciation. 3. Morphology: the branch of biology concerned with the form and structure of organisms. 4. The radula: a horny, tooth-bearing strip on the tongue of molluscs, used for rasping food (that is, scraping it off a surface). 5. Cytogenetics is a branch of genetics that studies inheritance in relation to the structure and function of cells.
Quest 2(4) 2006 9
Discovering our biodiversity ▲
which, because of their short generation times and accessibility, are ideal models for unravelling ecological and evolutionary processes. In the long term, we are aiming to highlight and conserve southern African small mammal biodiversity and to understand the processes that led to murid rodent biodiversity. A multidisciplinary approach in systematics Top: A new species of Doratogonus, D. in particular and science in general provides infragilis, described in 2000 by Michelle a solid basis for more robust results and Hamer from the south coast region of conclusions than previously, when our studies KwaZulu-Natal. This species is among were based on single techniques6. the ‘endangered’ ones on the IUCN Our work has shown how little we know Red Data List. about the way in which southern African murid Photograph: Marion Burger rodents disperse, or about their distributions, Middle and below: Line drawings biology, and evolutionary relationships. Our of Doratogonus gonopods. These multidisciplinary approach has not on the modified millipede legs are complex whole been used simultaneously for studying structures with loops, twirls, hairs, these rodents in particular, or African rodents and spines. The actual height of the in general, and our results suggest a far more pair (middle) is about 4 mm; that complex diversity in medically and agriculturally of the single gonopod (below) is important rodents than was previously thought. approximately 3 mm.
Knowing and saving our millipedes Michelle Hamer, University of KwaZulu-Natal There are about 450 known species of millipede in southern Africa. They come in all shapes and sizes – from the giant millipedes, which can be as long as 30 cm, to minute 0.5-cm bristly millipedes or the golf-ball-like pill millipedes. Probably most familiar are the large black “shongololos”. Because they look so similar, they’re perceived to be common and widespread, and biologists seldom collected them. A few species of large black millipedes were described in the 1800s and in the 1920s by foreign taxonomists, then a few more in the 1960s. When I began my career as a millipede taxonomist in 1994 at the Natal Museum, I started work on Doratogonus millipedes because I thought they would make for a simple project. At the time, 22 species were known from a limited number of localities. After examining the material in the South African museums, I realised that great areas in the country had not
been surveyed. Sampling trips to KwaZulu-Natal, North West, Limpopo, and the Free State showed me, moreover, that many species in my collection didn’t match the descriptions and diagrams of the species that were known, and that many of the named specimens in museum collections were wrongly identified. My three-year study led to the naming and description of 15 new species and to a better understanding of the distribution of all our millipede species. How do you tell one species from another, when long, black, many-legged millipedes all look the same? Only the males give useful information, because millipede taxonomists use the gonopods7 for distinguishing species. Each species has a distinctly shaped pair of gonopods and, by dissecting them, species can be identified. Why worry about the name of a millipede or to which species it belongs? Millipedes are abundant soil animals, important in breaking down fallen leaves and rotting logs and branches. Many birds, mammals, and insects feed on these animals, and losing a species from an area will have an impact on soil nutrient recycling and possibly also on food webs. A key way to protect a species is by recognizing the level of threat to that particular species. The IUCN Red List is a global catalogue of threatened species. If a species survives only in a small area, and if that area is threatened by development or environmental degradation, the species can be assessed and officially classified as ‘threatened’ on this list, which provides it with some status and protection. But, for this process, an accurate identification of the species and some knowledge of its distribution are critical. Many of the new species of Doratogonus that I described are found only in a small area, and several have officially been categorized as ‘critically endangered’ or ‘endangered’. We estimate that at least 300 more species of millipede remain undiscovered or undescribed, and a large number could become extinct. Unless we work hard, many may be lost forever before we have even named them. ■ Professor Crowe, at UCT’s Percy FitzPatrick Institute, has studied the evolution of gamebirds for nearly 40 years. He is a past-president of the Southern African Society for Systematic Biology and past chair of SABI. Professor Barker is with the Molecular Ecology and Systematics Group, in the Department of Botany at Rhodes University. Dr Herbert is Chief Curator of the Department of Mollusca at the Natal Museum, and has studied the taxonomy and systematics of southern African molluscs for over two decades. Professor Chimimba is at the Mammal Research Institute, Department of Zoology and Entomology, School of Biological Sciences, University of Pretoria. Professor Hamer, of the Inland Invertebrate Initiative at the University of KwaZulu-Natal, has conducted taxonomic research on fairy shrimps, velvet worms, and millipedes. Much of her current work focuses on invertebrate diversity and conservation in grassland, forest, and savanna biomes in KwaZulu-Natal.
6. Among the techniques that we use are: traditional morphometrics (which uses linear measurements to assess variation in size and shape); geometric morphometrics (a relatively new method which, more effectively than before, captures information about an organism’s shape and morphological evolution); cytogenetics (which is useful in establishing the status of species); and phylogenetic and phylogeographic analysis of molecular data (which helps to establish the taxonomic status of taxa and their evolutionary relationships). We also use palaeontological or fossil data, as well as ecological, biogeographic, and climatic material, and we interpret the information with reference to disease outbreaks. 7. Gonopods are modified legs on the seventh segment that the male millipede uses to transfer sperm packets to the female genital opening (which is on the second segment).
10 Quest 2(4) 2006
Q Careers in S&T
Careers in systematics Systematists start with a deep interest in nature, and many begin through hobbies such as bird-watching, or collecting shells, fossils, butterflies, and flowers, or through field research that exposes them to the diversity of species. They become passionate about ‘their’ group of organisms and can specialize in plants, mammals, birds, reptiles, frogs, fish, insects, snails, earthworms, protozoans, fungi, moulds, or even bacteria or viruses.
What do systematists do? The field accommodates many interests and lifestyles. Systematists can work outdoors, in a laboratory, or at a computer, and can contribute to conservation in many ways. They collect material in the field, often in littleknown or remote parts of the world; identify samples; extract and sequence DNA for analysis; publish research findings in scientific journals or disseminate them at conferences; capture data in databases; look after collections of preserved or living plants, animals, or microorganisms; and identify specimens for a wide range of clients. They often teach at universities and give talks to the public or to schools.
How can you qualify? Study life sciences at a university. Genetics, microbiology, plant pathology, entomology, zoology, botany, molecular biology, or any other B.Sc. subject in biology will start you off, and it’s best to have an M.Sc. or Ph.D. in some aspect of systematics. Relevant degree courses are available at most South African universities. For information about the types of research conducted at the different institutions, consult the websites of university departments for the fields listed here.
Who will employ you? There are relatively few qualified applicants when posts are advertised, which improves your chances of a job. Key employers include: museums, herbaria and other sections of the South African National Biodiversity Institute, universities, the Agricultural Research Council, the Medical Research Council, forestry research, and sugar and citrus research. Other posts are also available – in conservation or in private sector/industry research departments, for example – for qualified graduates who understand molecular techniques and can interpret molecular data or who can identify a wide range of plants, animals, or microorganisms. ■
A millipede-hunting expedition.
Right: The smoke is visibly reduced in the Basa Njego Magogo fire on the left.
Marlett Balmer explains how to make a coal fire that’s healthier and cheaper.
Low-smoke fires are best Coal can be cheaper than electricity for cooking, heating water, and keeping people warm. But coal fires make smoke, which is bad for everyone. Lighting a fire by the Basa Njengo Magogo (BNM) method means you can create a lowsmoke fire – and save money too. Smoke is bad for you Smoke causes air pollution, which kills about 2 000 children in South Africa every year from respiratory infections1. Burning wood, coal, or dung in households that aren’t well-ventilated makes the problem worse. A 2003 University of Pretoria study found that household coal burning contributed as much as 65% to the area’s air pollution. A 2004 study reported that domestic coal fires in the city of Johannesburg contributed 48% to measurable particulate emissions (that is, separate particles discharged into the air). So it’s always worth cutting down on smoke. The BNM solution Basa Njengo Magogo (BNM) means ‘to make fire like Granny’ in Zulu and Xhosa, and the method was named after Granny Mashinini. When the Nova Institute tried out an old ‘Scotch-fire’ approach in the eMhalenhle community near Secunda in the late 1990s, it didn’t work – until Granny Mashinini improved the design by adding coal on top of the burning wood. The BNM procedure influences the way in which coal combusts in the lighting process, and reduces visible smoke by up to 50% if the fire is built the right way. It works well in braziers or mbawualas, coal stoves, and even open coal fires as used for funerals, weddings, or community feasts. The fire is made at the top of the stove, so it provides instant heat for cooking, which means you need less coal – and it also seems to last longer. Try it and see for yourself! ■ Marlett Balmer of PDC (Palmer Development Consulting) is a researcher and consultant. She received the Eskom eta Woman in Energy 2003 Award for her contribution to South Africa’s energy sector.
Light a Basa Njengo Magogo fire Step 1 Put coal in the brazier (mbawuala) or stove, using a little less than normal.
Step 2 Place 3 or 4 sheets of newspaper on top of the coal.
Step 3 Put normal-sized pieces of firewood on top of the paper, adding 2 or 3 pieces more than you usually use.
Step 4 Light the fire. Wait till the wood is burning well.
Step 5 Add 1 or 2 handfuls of coal on top of the burning wood.
Graphics courtesy of the Department of Minerals and Energy, BnM Strategy
Watchpoints ■ Use enough wood – if you use too little, your fire won’t be hot enough to light the coal that you place on top of it. ■ Put enough coal on top – if there’s too little coal on top, your fire will die, or it won’t get hot enough to light the coal at the bottom. ■ Don’t put too much coal on top – too much coal on top will make your fire smoky. One or two handfuls is enough (depending on the size of your stove or mbawuala). ■ If your fire smokes after 5 minutes – you’ve probably put too much coal on top. Remove some of the extra coal to reduce the smoke.
1. Air pollution is considered the sixth biggest killer of children under the age of 4 years in South Africa. The Trade and Industry Chamber reported in 2004 that illnesses due to air pollution cost the government about R1.2 billion a year.
Quest 2(4) 2006 11
Football fever keeps growing as the 2010 World Cup approaches. Jos Lurie explains the principles for a new, improved, unique football that he has designed for South Africa.
all games have a long history, and ball designs have been modified over the centuries. In medieval Europe, inflated pig’s bladders were used. In America in 1836, Charles Goodyear patented vulcanized rubber1 and, in 1855, he designed the first vulcanized rubber football, consisting of four crescentshaped segments glued together. In 1862, H.J. Lindon developed inflatable rubber bladders for use in the American game. The Buckminster ball On the other side of the Atlantic, the founding of the English Football League in 1888 introduced the large-scale manufacture of balls. Round, leathercovered, inflated rubber bladders were developed with time. The designs mostly consisted of 6 panels each comprising 3 strips, giving 18 strips that were sewn together. This design with modifications lasted until the 1960s, when it was gradually replaced by the so-called Buckminster ball, named after Richard Buckminster Fuller, the US architect and engineer credited with developing the geodesic dome2. This ball design consists of 20 regular hexagonal and 12 regular pentagonal panels fitted together. The two polygons on which it is based (a dodecahedron and an icosahedron)3 were nothing new, being familiar to the ancient Greek philosophers. Known by mathematicians as two of the Archimedean solids, this ball design represents a truncated icosahedron. Since taking on the Buckminster design as their foundation, the balls used in successive World Cup tournaments4 have each been portrayed as ‘new’, but the description has applied to the superficial decoration, the construction technology, and the materials used. The 2006 World Cup ball was the first in recent times to deviate from the basic Buckminster model.
A recommended new design for the South African 2010 World Cup.
Designing a perfect football A World Cup football must fulfil the requirements laid down by the Fédération Internationale de Football Association (FIFA). It must be spherical, made of leather or other “suitable material”, with a circumference of between 68 and 70 cm, and weighing between 410 and 500 g at the beginning of the match. The pressure inside the ball must be between 0.8 and 1.1 atmospheres. Features that depend on the quality of materials and construction technology (and which apply to all designs) are based on the fact that wetness degrades the behaviour of the ball. It is therefore a requirement that covering materials and panel junctions should have a high degree of waterproofing. FIFA stipulates a maximum of 10% gain in weight during a match, to accommodate the absorption of moisture. Retention of shape, size, and pressure during the game are also obvious requirements. The first specification, that the ball must be spherical, depends on its design. The greater the sphericity or roundness of the football, the more true is its flight – a perfect sphere should behave perfectly in flight. If the football is constructed of panels (as all of them currently are), the symmetry of their arrangement and of their junctions also becomes a major factor
Top left: A standard football design used in the late 1930s. Middle left: The basic Buckminster ball design, used for the World Cup tournament in 1970. Left: The design of the German 2006 World Cup ball (the Adidas Teamgeist). 1. Vulcanized rubber is rubber that is treated with sulphur or sulphur compounds at a high pressure and temperature, to improve its elasticity and strength (or to produce a hard substance such as vulcanite, which, being resistant to chemical attack, is used for chemical containers, electrical insulators, and the like). This design confers great strength and allows robust structures to be built with relatively lightweight materials. 2. A geodesic dome is a very strong structural framework of triangles broadly forming a sphere or part of a sphere. 3. A polygon is a plane figure with many sides and angles; a pentagon has five sides and angles and a hexagon has six. A dodecahedron is a solid figure with 12 faces and an icosahedron is a solid figure with 20 faces. 4. In 1930, the Fédération Internationale de Football Association (FIFA) organized the first worldwide competition for the Jules Rimet cup (commonly known as the World Cup).
12 Quest 2(4) 2006
Top right: The derivation of the Buckminster ball: a combination of a dodecahedron (a) and an icosahedron (c) by mutual truncation (b). Mutual truncation: The pentagonal panels (yellow) of the Buckminster ball design are created by slicing the corners (or apices) of the icosahedron at right angles to a line connecting them to the centre of the ball.
Below right: The derivation of the recommended 2010 ball design: a combination of dodecahedron (d) and triacontahedron (f) by mutual truncation (e: as explained in the caption for b). The rhomb faces of the triacontahedron in this combination have their major and minor axes in the Golden Ratio [(√5 – 1):2], which means that 4 of the angles of the hexagon are 121.717484...° and 2 of the angles are 116.56504...°. These angles have been adjusted to 121.5° and 117°, respectively (maintaining the mathematical requirement of 720° for the sum of the interior angles of a hexagon). This adjustment does not affect the symmetry, but improves the sphericity in that the sum of the angles at each apex is the same, namely 351°, and nearer to 360° (the sum of the angles between the edges of adjacent panels meeting at an apex, if the ball were laid flat). This compares with the 348° of the Buckminster ball.
the sphere through the middle along this line, you would have two identical halves that, in their original position, reflect one another. The plane along the cut that’s been made is known as a ‘plane of symmetry’. In terms of these elements of symmetry – the axes and the planes – a sphere has an infinite number of axes, each of infinite symmetry, and an infinite number of planes of symmetry. Thus the sphere is the most symmetrical shape there is. Footballs comprise polygonal panels joined at the edges. Almost certainly, the greater the symmetry of the ball, the more stable – that is, the smoother – its flight is likely to be. The arrangement of polyhedra of both the Buckminster ball and the proposed 2010 design has maximum symmetry, namely: 6 fivefold, 10 threefold, 15 twofold axes of symmetry, and 15 planes of symmetry. The 2006 World Cup ball, however, has only 3 twofold axes of symmetry and 3 planes of symmetry. Comparing the three footballs, therefore, the German 2006 World Cup ball is highly spherical, but far less symmetrical than the other two.
controlling the ball’s trajectory when kicked. Of course, being made of leather and stitched or otherwise bound together, the panels are pliable and collectively approach sphericity under pressure when the ball is inflated. In other words, the panels are not flat (or planar) when the ball is played. The best of three The symmetry of the panel arrangement in the Buckminster ball design is much higher than that of the 2006 World Cup ball, although the 2006 ball has high sphericity because the panels are spherically moulded. Our design – which we are recommending for consideration for South Africa for 2010 – has the high symmetry of the Buckminster ball but its sphericity (in terms of geometry) is greater. The ball that we have designed for possible use in 2010 has maximum polygonal symmetry in terms of rotation axes and planes of symmetry. A definition of the symmetry follows. Imagine that you’ve driven a rod through the ball from a point on the surface, so that it passes through the centre of the ball and emerges at a point exactly opposite. Now, hold the two ends of the rod, rotate the ball through a complete revolution (360°), and observe the appearance (or pattern of surface features) that you see. If you see the same appearance or pattern more than once, the rod represents an ‘axis of symmetry’. If the ball is perfectly spherical and has no surface features, you will see the same appearance continuously: the rod would then represent an ‘axis of infinite symmetry’. This will not be the case if there are surface features to be taken into account. Where surface features change, the look of the ball as you see it from different points of view will be different. If you see the same appearance twice during a complete 360° revolution, the axis is called a ‘twofold rotation axis of symmetry’. If you see the same appearance three times, it’s called a ‘threefold axis of symmetry’. Similarly there are fourfold, fivefold, and more axes of symmetry. Next, imagine a line drawn to mark the circumference of the sphere (known as a ‘great circle’ – the line around the Earth that we call the Equator is such a line). If you were to cut
Top left: The symmetry of the new football design for 2010. The axes of symmetry are labelled numerically; the planes of symmetry are represented by the lines. Above left: The symmetry of the 2006 World Cup football. The twofold rotational axes of symmetry are labelled numerically; the intersections of the planes of symmetry with the ball’s surface are represented by lines. This ball has very low symmetry.
Quest 2(4) 2006 13
The geometry of the three ball designs No. of panels
Axes of symmetry
Planes of symmetry
32 (20 hexagons & 12 pentagons)
6 fivefold, 10 threefold, 15 twofold
2006 World Cup
14 (6 propeller-shaped; 8 with 6 sides, of which 3 are straight and 3 are curved)
South Africa 2010 recommendation
42 (30 hexagons & 12 pentagons)
6 fivefold, 10 threefold, 15 twofold
A comparison of the Buckminster ball with the new design that we are recommending for South Africa in 2010 shows that the two have the same symmetry, but the number of panels differs. The Buckminster ball has 32 panels while our 2010 ball design has 42 panels. This makes the 2010 design more spherical because, all other things being the same (such as the materials, the inside pressure, and the technology for joining the panels), the greater the number of symmetrically arranged panels the greater the sphericity of the ball (see figure). The 12 black pentagons of the Buckminster ball design help players visually to track the curve of the ball as it moves during a game. The 12 rings – sporting the colours of the South African flag – placed equally symmetrically around the surface of our proposed ball for 2010, are designed to fulfil the same function5. The three balls also vary in terms of the total length of seams that they carry, although their diameters conform to the FIFA requirement of between 21.64 and 22.27 cm. The Buckminster has an approximate total seam length of 438 cm, while the design for South Africa 2010 has a seam length of about 490 cm. The seam length of the 2006 World Cup ball, at about 338 cm, is less than those of the other two, and the arrangement of seams has a far lower symmetry, which may have an adverse effect on the aerodynamics.
A very spherical ball. This figure is a hypothetical extension of the recommended 2010 design. So many panels make the sphericity greater than any other ball – but also completely impractical to manufacture.
A winner for South Africa? The concept that has been outlined here examines the complex geometry that goes into the design of a perfect football. Could it in practice revolutionize the design of the world’s future footballs? Will South Africa accept it as a winner? Watch this space! ■ Jos Lurie, emeritus professor of the University of Johannesburg, has a special interest in solid geometry. He lectures in gemmology and researches polyhedra. His textbook on geology has gone to nine editions.
The controversial 2006 World Cup Match Ball Who’s right? The jury is still out. What do you think? ■ It’s “the technologically most advanced football ever made” featuring “a revolutionary new panel shape allowing players significant improvements in accuracy and control” (according to the FIFA World Cup web site at http://fifaworldcup.yahoo.com/06/en/051205/1/5h9j.html). ■ It is “goalkeeper unfriendly” and its unique panelling makes it “move unpredictably”, “flutter”, and “wobble”, even though a Sheffield University study claims that “the increased number of fluctuations – what looks like wobbling – allows the ball to ‘correct’ itself before reaching its target, which results in a more consistent shot” (reported by Matt Smith in Time, 3 July 2006, p. 40) ■ In conversation with Jos Lurie, Kevin Knowles (in the Department of Materials Science and Metallurgy, Cambridge University) confirmed that he had conducted superficial wind tunnel tests on several balls, including the Buckminster and the 2006 World Cup ball. Preliminary indications were that all the balls oscillated (or ‘wobbled’) but that the 2006 ball oscillated most. He agreed that both symmetry and seam length were possible factors in these results, and that short seam length could have an influence in disturbing the flight trajectory.
5. The aerodynamic behaviour (that is, the trajectory through the air) of the ball that we have designed for South Africa has not yet been tested. This article simply explains some of the geometric principles that could have an effect.
Standards to maintain Last year, the Netherlands Measuring Institute moved to a new home outside the city of Delft. Its old premises in the city, housing the national standards of time, weight, length, pressure, and so on, were neighbours to another research institute that regularly conducted vehicle crash tests. NMI director Dr Jan Ridder says: “The sheep grazing in the fields around our new building are vibration-free and that makes all the difference.” In South Africa, the CSIR’s National Metrology Laboratory has the job of maintaining standards of physical quantities and comparing them with other national standards.
Tall story Agilent Technologies’ online Metrology Forum jokes about the difference between managers and metrologists. A group of managers was asked to measure the height of a flagpole. They fetched a ladder and tape measure and set about the task, but
kept dropping the tape and falling off the ladder. A metrologist offered help. She pulled the flagpole out of the ground, laid it flat, and measured it. “Typical metrologist,” a manager grumbled, “we’re looking for the height and she tells us the length.”
Wet and what else? ■ There are many ways to measure water. Its turbidity, for example, is the amount of particulate matter suspended in water and expresses the scattering of light by these solids. Turbid, or opaque, water has a high count of nephelometric turbidity units (NTU). ■ You can also measure water’s pH in a range from 0 (acid) to 14 (base). Water containing more free hydrogen ions is acidic and that with more free hydroxyl ions is basic. Like the Richter scale, pH is a logarithmic measurement, with each successive number representing a change of 10 times the concentration of hydrogen ions.
Q Measuring up ■ Specific conductance is a measure of water’s ability to conduct an electrical current. Pure water has low specific conductance and water containing more dissolved solids has higher specific conductance. ■ The Earth’s total water supply is 1 400 000 000 km³. Each year, 119 000 km³ of water precipitates on land and 74 200 km³ evaporates. Annual precipitation on ocean and sea surfaces is 450 000 km³ and evaporation 502 800 km³. Fresh water stored in glaciers and icecaps accounts for 24 500 000 km³ of water, or 69.5% of all fresh water. Oceans store 97% of the world’s water total. Less than 1% of the water supply on Earth can be used as drinking water. Sources: The US Geological Survey, Lenntech.
Quest 2(4) 2006 15
Alcohol has a devastating effect on a developing fetus. In some South African communities, one in every twenty children of school-going age suffers from the incurable condition called Fetal Alcohol Syndrome. But it’s preventable, explain geneticists Lillian Ouko and Michèle Ramsay. To protect an unborn child from such harm, avoid alcohol when you’re pregnant.
developing fetus is most vulnerable to the effects of alcohol in its first three months, as that’s when critical organ systems are being formed. So if an expectant mother drinks at that time, her baby can be born with a small and poorly developed brain as well as malformations of other organs. These are two of the most severe presentations of the condition called How much is too much? We don’t know for certain what amount of alcohol is ‘safe’ for an expectant mother to consume during pregnancy, but it seems to differ for different people. Adverse effects have been observed in children who were exposed during pregnancy to as little as half a drink per day (a can of beer) as well as in individuals whose mothers indulged in binge drinking (that is, who had more than 5 drinks in a sitting, where 1 drink = 15 ml of absolute alcohol, or one glass of wine or 2 cans of beer). ■ The safest amount is NO ALCOHOL AT ALL during pregnancy, nor in the period before conception.
Fetal Alcohol Spectrum Disorder (FASD). The brain goes on developing throughout the nine months of pregnancy, so alcohol use at any point can jeopardize the mental capacity of the unborn child. This mental deficiency is the defining and most devastating feature of FASD. The symptoms of the condition can vary in seriousness and in kind, and they cannot be cured. But FASD can easily be prevented. All that’s needed is for an expectant mother to avoid alcohol completely before conception and during her pregnancy. Then her baby is safe from such danger. Is it just drinking alcohol during pregnancy that causes this disorder? Or does genetics put some people at greater risk than others? South African researchers are investigating unique genetic factors that may increase vulnerability to FASD. This means that
communities that are genetically most susceptible could be targeted for special prevention and intervention strategies. What is FASD? In as early as the 18th century, there were reports of “weak, feeble and distemper’d children” being born to heavily drinking parents in London. But not until 1968 was it first defined as a clinical disorder directly related to maternal drinking during pregnancy. It was subsequently named Fetal Alcohol Syndrome (FAS). The early studies by French and American scientists showed that alcohol consumption by an expectant mother could lead to an underdeveloped child, characterized by mental and growth deficiencies and distinctive facial features. The Mothers and infants at one of the clinics awaiting health screening and FASD assesment.
No alcohol if you're pregnant! 16 Quest 2(4) 2006
No alcohol if you're pregnant!
Range of FASD symptoms
Physical characteristics ■ Facial features • Long smooth midline groove in the upper lip • Thin upper lip • Small wide-spaced eyes ■ Delayed growth before and after birth ■ Small or abnormal brain ■ Cardiac defects ■ Skeletal defects ■ Kidney dysfunction ■ Eye abnormalities ■ Hearing loss ■ Minor anomalies • Impaired immune function • Skin and nail abnormalities • Small 5th digits (little fingers).
A unique heritage It was not clear why some South African groups of people carry this excessive burden of FASD, when others with similar risk factors appear less affected. The communities in South Africa with the highest FASD rates are DNA and the Demon Drink All humans are 99.9% similar genetically, but the 0.1% difference contributes to the variable responses we have towards exposure to pathogens such as HIV or TB and to environmental factors such as alcohol consumption and inhalation of asbestos fibres. The genetic variation also contributes to susceptibility to complex genetic diseases including asthma, heart disease, and diabetes. The most common differences among the DNA molecules of individuals are changes at a single position in the sequence from one nucleotide to another, referred to as single nucleotide polymorphisms (SNPs). These SNPs are important, particularly when they occur in regions of the genome that directly code for proteins or regulate protein expression. Individuals with SNPs in genes that ■ encode for proteins involved in the breakdown of alcohol ■ are directly or indirectly affected by alcohol, or ■ are involved in the developmental processes that are affected by alcohol can have variable responses to alcohol exposure.
Genetic variation Person 2
great variations in the specific clinical features, however, led to the condition being redefined as Fetal Alcohol Spectrum Disorder, which describes the range of effects on the developing fetus of a drinking woman. FAS is now the term used to describe just the most severe form of FASD, and other terms are used to define forms that affect individuals to a lesser extent: Fetal Alcohol Effects (FAE), Prenatal Alcohol Effects (PAE), Alcohol Related Birth Defects (ARBD) and Alcohol Related Neurodevelopment Disorder (ARND). FASD is accompanied by mental and behavioural problems, growth deficiencies, distinctive facial features, and organ defects. The distinctive facial features diminish with age but the mental, behavioural, and clinical symptoms are lifelong. FAS individuals can end up as school dropouts, unemployed, or abused, and many engage in promiscuity and crime. If they are not diagnosed soon enough, they can often suffer early death. To integrate those who suffer from FASD into society, determined lifelong therapy and health monitoring are crucial.
Fighting FASD in South Africa In the early 1990s, paediatrician and geneticist Denis Viljoen became aware of the devastating effects of alcohol on certain coloured communities in the Western Cape. He started the Foundation for Alcohol Related Research (FARR) in 1996, which, in collaboration with doctors and scientists in South Africa and the USA, aims to define the extent of the problem in South Africa and to work with government institutions to address the issue of prevention. At over 5% of school-entry children, FASD-prevalence statistics in some Western Cape communities are alarmingly high. The situation is even worse in certain Northern Cape communities, where 7–10% of children are classified as FASD. Similar studies performed in developed countries have indicated rates that are 30–50 times lower. In the USA, for example, the incidence of FAS is only around 0.1–0.5%. Why are there such high rates of FASD in the Western and Northern Cape? Lurking behind the glamorous façade of South Africa’s wine industry is a legacy of alcohol abuse among vineyard workers. This was institutionalized by the ‘dop’ system, whereby farm workers were given wine as part of their weekly wages. These communities developed a culture of drinking, with detrimental effects ranging from unemployment, poverty, crime, and promiscuity to domestic violence and unwanted pregnancies. In cultures that accept regular heavy drinking as the norm, excessive drinking also occurs during pregnancy and, inevitably, results in the high prevalence of FASD. Studies have shown that almost 50% of pregnant rural women in the Western Cape drink alcohol compared to 34% of women living in urban areas. Further risk factors include low socioeconomic status, ignorance of the effects of alcohol during pregnancy, binge drinking, older expectant mothers (over the age of 35 years), and lack of access to primary health care. Other communities in the world with similar cultures of excessive drinking and comparable risk factors – such as those in Russia and Native American communities in the USA – do not share
these shocking statistics, however. This was a puzzle for researchers.
Mental and behavioural abnormalities ■ Poor performance in complex tasks • Problem-solving • Planning • Judgment • Abstraction • Language skills • Academic work ■ Disordered behaviour • Difficult personal manner • Hyperactivity • Emotional instability • Difficulties with memory and attention • Deficient social skills
The cost to the individuals, their families, and society is enormous. In the USA, where statistics are available, it is estimated that FAS-related health costs are around US$75 million per year.
DNA variation Single nucleotide polymorphism
. . . A C G T TA . . .
. . . A C G A TA . . .
DNA (deoxyribonucleic acid) is found in each cell of the body and contains the genetic information to produce all the components of an individual. DNA is a helical molecule made up of two strands of nucleotide bases comprising adenine (A), cytosine (C), thymine (T) and guanine (G), anchored on a sugar phosphate backbone. The arrangement of the bases on the DNA strand is similar in each individual with only slight variations occurring. The most common variation is a change at a single nucleotide position from one base to another (for example, a T to an A). These are called single nucleotide polymorphisms (SNPs), which result in individuals having different ‘alleles’ in particular DNA locations. (An allele is one of the alternative forms of DNA found at the same place on a chromosome.) Some SNPs have been associated with disease.
Quest 2(4) 2006 17
Case-control association study General population
FAS-affected individuals are more likely to have a T allele
Normal individuals are more likely to have an A allele T allele A allele
A general population has individuals with different alleles at various DNA locations. To determine whether a particular allele in a gene (for example, ADH4 ADH4)) is associated with a particular condition (such as FAS), individuals are identified who are FASaffected, and the alleles of the affected individuals (a T or an A) are compared with alleles in unaffected individuals from the same population. If most individuals with FAS have a particular allele (T) relative to the normal population, that allele is said to be associated with FAS. This means that a fetus with a T allele is more likely to develop FAS when its mother drinks during pregnancy. For a complex disorder such as FAS, no single allelic difference will determine whether an individual will develop the condition but rather a combination of allelic differences in several locations in the DNA.
populated largely by coloured people, which raises the question: Could their unique genetic heritage be a factor contributing to FASD development? The South African coloured population originated from the intermixing of people from distinct groups including Khoi, San, European, Malay, and Bantu-speakers, and created communities with unique and varied genetic compositions. As these communities became segregated geographically, they attained unique cultural and genetic identities. The role of genetics Although it is well known that genetics plays a role in alcoholism, its role in FASD is unclear. Not all mothers who drink heavily during pregnancy have
18 Quest 2(4) 2006
children with FASD, which led scientists to conclude that genetics might also influence the risk of developing this condition. Furthermore, there have been cases where non-identical twins born to a mother who drank heavily during pregnancy developed differently, one being normal and the other being affected by FASD. Mouse studies supported the hypothesis that inheritance could affect the result of exposure to alcohol during pregnancy. Particular mouse strains have offspring with FASD features when exposed to alcohol during pregnancy, whereas other strains do not. Clearly then, exposure to alcohol in addition to the genetic make-up of the individual and his or her mother determines whether or not FASD develops. In some South African communities, both genetic and social factors may have contributed to the creation of a pool of individuals who are more susceptible to the adverse effects of alcohol. The aim of our research has been to identify the genetic factors and their role in the risk of developing FASD. Application to South African populations Our investigative approach is to perform a ‘case-control association’ study. Using volunteers from the same communities, we compare gene variants in a group of FAS-affected individuals with those in a group of control individuals. Our research team, headed by Michèle Ramsay, has worked mainly with two communities in the Northern Cape (Upington and De Aar) and one in the Western Cape (Wellington). Viljoen and his colleagues have established several intervention programmes in these communities that include ■ educating them about the direct link between alcohol and FASD ■ early identification and monitoring of FAS (from birth to the age of 6 months) ■ comparing lifestyles and habits of mothers with FAS to those of mothers unaffected by it A young girl with her mother, from a high risk community.
■ nutritional supplementation to mothers (underweight mothers tend to be at higher risk of FAS-affected children) ■ collecting information to monitor the effectiveness of intervention programmes. The genetics research group works in close collaboration with the intervention programme to recruit further volunteers for the ongoing genetic research. Children between the ages of 6 months and 7 years (the age where diagnosis is most easily made) who are diagnosed with FAS make up the FAS-affected group, and adult members of the community make up the control groups. DNA samples are then studied in the laboratory for variations in the DNA sequence. The data are analysed to detect whether or not any statistically significant, or ‘real’, differences exist between the variants found in the control group and those in the FAS group. Identifying the suspect genes Some genes were clear candidates for investigation: those encoding proteins that play an important part in metabolizing alcohol, and those producing proteins that participate in the developmental processes that are impaired by exposure to alcohol. Our study focused on the following genes: ■ Alcohol dehydrogenases (ADHs), which break down alcohol. This family of genes has several members, and there are known genetic variants that affect the efficiency with which alcohol
No alcohol if you're pregnant!
is broken down. The difference in alcohol tolerance observed amongst individuals and within some racial groups is based largely on the variants of the alcohol dehydrogenases present. Several studies have also demonstrated a link between alcohol dependence (alcoholism) and specific variants of ADH. ■ Genes involved in the migration of neural cells during development. Deficiencies of these genes can result in impaired mental functioning. ■ Genes whose expression is important for the proper development and growth of the fetus. Examples include the insulin growth factor and its associated genes, as well as genes that modify the expression of other genes through a process that attaches chemical tags, or methyl groups, to silence genes at critical times during development. Our selection may miss some critical genes that are not immediately obvious choices for study, so we are developing computational methods to identify additional candidate genes. The computer algorithms extract and organize information from the biomedical literature and genomic databases, and identify links between alcohol and developmental pathways specifically related to fetal brain development. Several different genes play a role in alcohol’s effect on the body, and this approach helps to identify classes of functionally related genes that, working together, could contribute to a greater FASD susceptibility than any single gene on its own.
Putting research to work Our research has highlighted at least one molecular pathway that influences the effects of alcohol exposure in the fetus. Most important, it has also helped us to determine susceptibility variants, which, in turn, brings us closer to using genetic variation to identify sub-populations at particular risk of developing FASD. Such high-risk groups could be targeted for aggressive prevention and intervention strategies that are too expensive to implement more widely.
Alcohol consumption by mother 1st trimester exposure Alcohol Acetaldehyde
In the liver:
Alcohol ADHs Acetaldehyde
Fetal Alcohol Syndrome ■ Growth deficiency (small body) ■ Poor brain development (small head) ■ Distinctive facial features When alcohol is consumed it enters the bloodstream. It is broken down, primarily in the liver, into metabolic by-products and alcohol is removed from the blood. Alcohol dehydrogenases (ADHs) are the enzymes responsible for the breakdown of alcohol into acetaldehyde. If a woman drinks alcohol excessively during early pregnancy, her blood alcohol levels increase and the fetus is exposed (via the placenta) to high levels of alcohol and acetaldehyde, both of which are teratogenic (that is, harmful to fetal development) and can cause Fetal Alcohol Spectrum Disorder. The fetus is most vulnerable to the effects of these teratogens during the first trimester. Graphic: Marco Weinberg, Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand
The range of strategies (such as those in place in the focus communities in the Northern and Western Cape) include pre-pregnancy education, warnings against the dangers of drinking in early pregnancy, nutritional supplements for pregnant women and underweight children, post-pregnancy counselling, behavioural training for children diagnosed with FASD, training
Some genetic risk factors identified It is clear that the major non-genetic risk factors for FASD are maternal drinking, low socio-economic status, and poor nutrition, so concerted efforts are needed in these areas. But genetic risk factors have now also been identified. The alcohol dehydrogenase (ADH) genes, for instance, which have been shown to play a role in genetic susceptibility to alcoholism in many populations worldwide have now been linked to susceptibility to FASD. In the South African coloured population, our research has demonstrated that the ADH1B*2 variant is significantly more common in the
control group than in the mothers of the group of FAS-affected children. This finding highlights the importance of the genetics of the drinking mother as an influence on the consequences of her drinking on her unborn child. We cannot ascertain, however, whether mothers with this variant are less likely to be alcoholics and therefore have fewer children with FAS, or whether the ADH1B*2 variant confers biological protection on the fetus, or whether a combination of both factors plays a role. Studies on ADH4 gene variants have also demonstrated a significant difference between the control group and the FAS-affected group. It is clear, therefore, that the way in which an individual metabolizes alcohol is a considerable risk factor. Variations in genes that encode proteins participating in alcohol metabolism are important in assessing susceptibility to FASD, in both mother and fetus. Our results have also indicated differences in the genetic backgrounds of the coloured populations in the Northern and Western Cape. These differences are being investigated further to help us to understand whether or not the genetic variants that are important in assessing FASD susceptibility in one population are also important in the other.
Children at the Joan Wertheim centre in De Aar.
Quest 2(4) 2006 19
No alcohol if you're pregnant!
the 18th-century writer who reported on the “weak, feeble and distemper’d children” of parents who drank heavily was, inadvertently, referring to the role of both parents in the susceptibility of their children to FASD.
Children enjoying the boerewors rolls supplied during FAS day. ▲
Help is available ■ Foundation for Alcohol Related Research (FARR) Tel. (011) 489 9239 (www.farr.org). ). Johannesburg (011) 489 9509, Cape Town (021) 406 6210, De Aar (053) 631 0562, and Upington (054) 332 4950. ■ Pebbles Project Tel. (072) 472 2797 (www.pebblesproject.co.za/fasd. www.pebblesproject.co.za/fasd. html). ■ Alcoholics Anonymous Johannesburg (011) 436 0797, Cape Town (021) 592 5047. Visit www.alcoholics.org.za ■ South African National Council on Alcoholism Tel. (011) 482 1070 (www.sancanational.org.za www.sancanational.org.za) ■ Ann Streissguth’s book, Fetal Alcohol Syndrome – A Guide for Families and Communities Communitie (Paul H. Brookes Publishing, 1997).
For information about recent research, consult Hoyme, H.E. et al., “A practical clinical approach to diagnosis of fetal alcohol spectrum disorders: clarification of the 1996 Institute of Medicine Criteria”, Pediatric, vol. 115 (2005), pp.39–47; Viljoen D.L. et al., al. “Characteristics of mothers of children with fetal alcohol syndrome in the Western Cape Province of South Africa: a case control study”, Journal of Studies on Alcohol, vol. 63 (2002), pp.6–17; Viljoen D.L. et al., al. “Fetal Alcohol Syndrome epidemiology in a South African community: A second study of a very high prevalence area”, Journal of Studies on Alcohol, Alcohol vol. 66 (2005), pp.593–604; Viljoen D.L. et al.,, “Alcohol dehydrogenase 2*2 allele is associated with decreased prevalence of fetal alcohol syndrome in the mixed-ancestry population of the Western Cape Province, South Africa”, Alcoholism: Clinical & Experiential Research, vol. 25 (2001), pp.1719–1722; May, P.A. et al.,, “Epidemiology of fetal alcohol syndrome in a South African community in the Western Cape Province”, American Journal of Public Health, vol. 90 (2000), pp.1905–1912.
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in early diagnosis for community medical professionals, and awareness programmes in schools and communities on the management and care of people suffering from FASD. Just one binge can cause the damage Studies in mice have shown that giving a pregnant mouse a single high dose of alcohol causes a higher than normal rate of fetal death and the development of FAS features in embryos that survive. Now we are conducting further studies to examine the effect of alcohol on key developmental genes in the offspring of female mice exposed to a single high dose of alcohol during early pregnancy. The effect of drinking fathers Studies on mouse models have shown that FASD is associated with the alcohol usage of expectant mothers. But male mice that are given alcohol for long periods before conception can cause changes in the neurodevelopment of their offspring, even when the mother is not exposed to alcohol at all during pregnancy. Further studies are under way to understand the role of paternal drinking on the outcome of a pregnancy in humans. Perhaps
Remedial action The effects of drinking during pregnancy can be devastating, irreversible, and incurable, causing a life of mental and social disability. Whatever the genetic make-up of an individual, however, FASD is completely preventable in everyone. This is why it’s strongly recommended that all women who have a chance of falling pregnant should consume no alcohol at all. Communities need to be aware of the serious dangers of drinking during pregnancy, and reliable contraceptive practices are best for individuals who drink regularly. If FASD is diagnosed early and accurately, however, people affected by it can be understood and appropriately supported. With the right kind of care from loved ones and trained professionals, they can reach their full potential, become better able to adapt socially, and, depending on the severity of their disability, become productive members of their communities. ■ Dr Ouko is a postdoctoral research scientist with the Foundation for Alcohol Related Research and The University of the Witwatersrand, and Professor Ramsay is in the School of Pathology at the National Health Laboratory Service and The University of the Witwatersrand and Head of the Molecular Genetics Laboratory. The other members of the FAS genetic research group are Zanè Lombard, Dhamari Naidoo, Shelley Macaulay, Philip Haycock, and Desmond Schnugh. FAS-affected child from one of the high risk communities.
Aerial view of the mouth region of the freshwater-deprived Kariega Estuary, illustrating the build-up of marine sediments in the mouth region. Photograph: Alan Whitfield, South African Institute for Aquatic Biodiversity
Where river meets ocean T
here’s something remarkable about exploring an element other than our own and enjoying the generosity of our oceans and rivers. But how do these different bodies of water interact and what effect does their meeting have on living organisms? New research is indicating that rivers could be more important than has previously been thought for the productivity of the sea into which they flow.
Water users People require fresh water; economic development requires it; and rivers themselves require it for ecological functioning. What about the sea? Our research team is finding out. South Africa is considered a water-poor country, with a mean annual runoff below that of the world average. To meet the needs of our growing human population, government and the private sector are investigating the establishment of more impoundments (such as dams) on our river systems. The new Water Act (No. 36 of 1998), however, recognizes the natural environment
How do rivers affect the abundance of life in the adjacent ocean? Paul Vorwerk and his colleague William Froneman offer preliminary answers.
Estuaries There are four naturally occurring aquatic habitats in South Africa: rivers, lakes, estuaries, and the ocean. While the physical boundaries between rivers and lakes are easily apparent to most people, those between rivers and the sea are more difficult to define. The aquatic habitat of estuaries forms this kind of boundary. Estuaries are defined as partially enclosed bodies of water, either permanently or periodically open to the sea, and their waters vary in salinity because of the varying mixture of sea water from the ocean and fresh water from the land. All river mouths and lagoons are estuaries. They are very productive and incredibly rich in biodiversity. Those in South Africa have many types of fish including several recreational linefish species such as spotted grunter, river bream, Natal and Cape stumpnose, and white steenbras. The more important among the invertebrates are the economically valuable swimming prawns, which also migrate between estuaries and the sea. These fauna use estuaries for a variety of reasons, depending on the
species. The animals that come from the sea use them as nurseries for juveniles and as feeding areas before they spawn; the riverine species use them to extend their habitat; and estuarine species complete their entire lifecycles there.
Estuary types in South Africa There are five major estuary types. ■ Permanently open estuaries. These systems maintain a permanent connection with the sea, and have a marine component, with seawater entering the river channel in varying degrees. ■ River mouths. These estuaries also maintain a permanent connection with the sea, but with minimal tidal intrusion into the river channel. ■ Temporarily open/closed estuaries. This type of estuary is the most common along our coastline, and is created by smaller rivers that maintain insufficient flow to allow a permanent connection with the sea. A sand bar develops during the dry season and prevents direct access to the sea. ■ Estuarine lakes. These are large bodies of water that may or may not have a permanent connection with the sea. They may be linked to the sea by a channel of varying length and limited tidal exchange. ■ Estuarine bays. These are large water bodies characterized by a wide mouth and strong tidal exchange. They are mainly marine dominated.
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Animals that use estuaries Estuarine animals enter these systems from the rivers and from the sea. Their ability to tolerate changes in salinity (salt content) levels (that is, their ‘salinity tolerance’) determines how far they penetrate into an estuary. If a marine species is relatively ‘salinity tolerant’ it penetrates an estuary up to the river entrance (such as the estuarine mullet, Myxus capensis). Marine species that are less ‘salinity tolerant’ stay behind in areas that approximate sea water. Salinity tolerance is a measure of the ability of a fish to survive in a range of saltiness from freshwater (zero parts per thousand), to highly saline (saltier than seawater, which is 35 parts per thousand). Most marine species are intolerant of fluctuations in salinity and cannot handle large increases or reductions. Some freshwater species, such as Oreochromis mossambicus, mossambicus are more tolerant of salinity fluctuations than marine species, and able to adapt to about three times the salinity of seawater (that is, 90 parts per thousand). The penetration of fish into estuaries – from the river or the sea – depends, therefore, on their tolerance of large changes in salinity from their normal environment. A classification system separates the fish into different types, with invertebrates classified in a similar way. There are five major divisions. 1. Estuarine-resident species. These complete most, if not all, of their life cycle within estuaries. These are normally small-bodied species of fish that tend to be detritivores or planktivores. 2. Marine migrant species. These enter estuaries from the sea for various reasons. The most common purpose is to use them as nursery areas. Larvae or juveniles enter the system and mature to a subadult or adult stage before leaving to complete their life cycle in the sea. The other common reason for entering estuaries is for pre-spawning nutrition. Because of the productivity of estuaries, adults come in to gather energy (by feeding) for spawning. This category is the most diverse of the marine fishes and represents many of our country’s recreational angling species. 3. Marine stragglers. These fish enter estuaries by accident, often on tidal currents when the mouth is open. Because they do not tolerate reduced salinity, they die if they do not return to the sea fairly quickly. 4. Catadromous and anadromous species. Named from the Greek, meaning “running downstream” and “ running upstream”, respectively, these species have both a freshwater and a marine phase in their life cycles, and they use estuaries as a transit route between the two. 5. Freshwater species. This group comes from the riverine environment and is characterized by relatively high salinity tolerances. Unfortunately, many of these are alien species. ▲
Top: Cape stumpnose ((Rhabdosargus holubi), an example of a marine migrant fish species. Photograph: Paul Vorwerk
Above: An estuarine roundherring ((Gilchristella Gilchristella aestuaria aestuaria), ), an example of an estuarine-resident fish species. Photograph: Paul Vorwerk
Right: Paul Vorwerk sampling zooplankton off the mouth of the Great Fish Estuary on a cold morning, illustrating the nets used to catch zooplankton. Photograph: Mike Jennings
How we studied the effect of rivers on the adjacent ocean The sampling in our study concentrated on the zooplankton and physical/chemical properties of the water column (that is, the ‘column’ of water between the sea surface and the seabed at the sample site). We chose zooplankton because of the difficulty of catching a representative sample of fish in the marine inshore zone. Sampling zooplankton is relatively easy and can be done at several sites in a single day. Sampling took place on three consecutive days, two days at sea and one in the estuaries. A sampling grid was established offshore of the estuaries, consisting of 24 sites, and 8 sites were selected within each estuary from the mouth to the head of the estuary. At each site, water was collected from the surface and midwater or bottom (at a depth of 5 m in the sea and from the estuaries’ floor), so that we could analyse particulate organic matter and chlorophyll. We also measured temperature, salinity, and turbidity, and undertook three replicate zooplankton surface tows. A small (50-cm-diameter) net with a fine mesh (100 µm) was lowered below the boat, with a flow meter (to determine the amount of water being sampled), and towed in a circle above the site. The zooplankton samples so collected were then preserved in formalin for later identification and counting. Once analysed, the zooplankton data were processed using computer software that displays the community structure (numbers of each individual contributing to a sample) at each site and compares them. In this way we could determine the similarity of the sites to each other, and group them accordingly.
– including rivers, estuaries, and the sea – as a legitimate user of water. As a result, the water needs of rivers downstream of impoundments have been investigated, and, currently, the freshwater requirements of estuaries are also being studied. So far, the importance of freshwater outflow to the sea has received little attention. We are unsure of the effect that further water abstraction could have on the marine inshore environment (that is, within 500 m of the beach including the surf zone). We need to identify to what extent this area relies on nutrient and biomass1 input from estuaries – essentially from river flow – to sustain its high productivity. Our research has tried to address this issue. Does the sea need river water? The study that we have conducted attempted to identify the effect of estuarine water on the sea. The adjacent marine environment is important because it has the potential to support large amounts of biomass. A dazzling example along South Africa’s east coast is the sardine run, which demonstrates the ability of the marine inshore environment to support extraordinarily large numbers of consumers and predators at times. Is this ability due mainly to what happens at sea or do estuaries make a contribution too? The coastal area is also important for its subsistence, recreational, and commercial use by humans, and for its biodiversity. Even though about 70% of the planet is covered by ocean, the biodiversity and faunal/floral biomasses are not uniformly distributed but are richer close to land. Off South Africa’s east coast, the continental shelf is not very wide, so the biomass in this region is even more concentrated. To examine the effect of freshwater flow from
1. ‘Biomass’ is the term used for the total quantity of living organisms in a given area, expressed in terms of living or dry weight per unit area or volume.
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Water transfer schemes Water transfer schemes are designed to transport water to places where it is most needed. In South Africa, mostly with the help of gravity (or pumping) and using tunnels and channels or aqueducts, large engineering works move huge volumes of water from a river basin or catchment area that is water-rich to another that is often water-poor. Such water transfer schemes often have disastrous consequences for aquatic environments. Currently, there are seven major water-transfer schemes in South Africa: the two largest are the Orange–Fish River Tunnel and the Thukela–Vaal Transfer Scheme, and the best-known is the Lesotho Highlands–Vaal Transfer Scheme. These constructions supply water demands in the receiving catchment, be they for industrial, domestic, or agricultural purposes. Although transferring water for human use is not seen by the public as damaging to the environment, problems do arise in the receiving catchments. Water transfer schemes result in many changes, including increased sedimentation, altered water quality, the introduction of new and potentially destructive species, and subtle shifts in the way in which the rivers interact with the marine environment. All these consequences can be disastrous to the biology in the receiving systems, so water-transfer schemes have to be considered with great care before they are implemented.
estuaries on the productivity of the adjacent sea, we investigated the zooplankton communities (assemblages of small animals such as prawn and crab larvae) in and adjacent to two Eastern Cape estuaries, the Kariega and the Great Fish. We chose these estuaries because of their open mouth status and the fact that they have contrasting freshwater flow rates. The Kariega Estuary receives relatively little fresh water because two large dams on the main river channel abstract large amounts of water from its catchment, as do several small farm dams. As a result, the Kariega River delivers a mere trickle of fresh water to the estuary – an average of only about seven litres per second. The Great Fish, on the other hand, has a substantial flow, due to an interbasin transfer from the Orange River, and averages as much as 11.5 million litres per second. We found that the marine environment adjacent to the freshwater-dominated Great Fish mouth had dramatically higher numbers of zooplankton (3 000–9 000 individuals per cubic metre) than those recorded adjacent to the freshwater-deprived Kariega River mouth (100–190 ind/m3). We were interested to discover that numbers of zooplankton in the marine environment opposite both estuaries were higher than those recorded in marine waters far away from an estuary (approximately only 15 ind/m3). The biomass of zooplankton that we recorded offshore of both systems showed a similar pattern of increase near the estuary mouths – although the recorded biomass and abundances opposite the Great Fish (ranging from 25–72 milligrams per cubic metre) were greater than those measured at the same time opposite the Kariega estuary (25–51 mg/m3). The build-up of zooplankton opposite both these estuaries – even the freshwater-deprived Kariega – suggests that it may result not only from freshwater outflow but also from some as yet unidentified factor for which the estuaries are responsible. We suspect that the presence of a food resource in the form of phytoplankton is being flushed from the estuary, and that there could be increased production of phytoplankton
in the estuarine/marine mixing zone due to the nutrients being discharged from the estuaries. But research is ongoing to provide the answers. Although our results are preliminary, they indicate that fresh water leaving the rivers along our coastline is likely to be important in increasing the productivity of the adjacent ocean. As far as we know, this study is the first to demonstrate an impact by freshwater on the biota (or plant and animal life) in marine areas close to estuaries. The effect of reduced freshwater flow on the adjacent sea needs to be investigated further, as it could have an adverse impact on the biota in the inshore marine environment. Furthermore, we do not know yet if it could also have a deleterious effect on recreational or commercial fisheries. So we need further investigations now, before more water is abstracted – interrupting the flow of fresh water from our rivers into the ocean. ■ Paul Vorwerk, a doctoral student in the Department of Zoology and Entomology at Rhodes University, specialized in estuarine research on fish and zooplankton before his current project of examining estuarine interactions with the sea. Professor William Froneman, in the same department, has extensive research experience in the study of zooplankton dynamics in the Southern Ocean and southern African estuarine ecosystems. The current ongoing study by the Rhodes University Zoology Department (funded by the National Research Foundation and the university) will attempt to identify seasonal patterns. It will be expanded to investigate the role of smaller rivers that are periodically closed off from the sea, and to ascertain whether or not they too contribute to the productivity in the inshore environment when their mouths open.
Top left: Aerial view of the Great Fish Estuary mouth region, showing the muddy estuarine water entering the marine environment. Photograph: Alan Whitfield, South African Institute for Aquatic Biodiversity Above: Contour plot of offshore zooplankton biomass as measured opposite the Great Fish and Kariega estuaries during December 2004.
For more about estuaries, consult A.K. Whitfield, Biology and Ecology of Fishes in Southern African Estuaries (Ichthyological Monographs of the J.L.B.Smith Institute of Ichthyology 2, 1998); J.H. Day, “What is an estuary?”, South African Journal of Science, vol. 76 (1980), p.198; and G. and M. Branch, The Living Shores of Southern Africa (Cape Town; Struik, 1993). For the Eastern Cape coastline and estuaries, read R.A. Lubke and I.J. de Moor (eds.), Field guide to the Eastern and Southern Cape coasts (Cape Town: University of Cape Town Press, 1998). You’ll also find more by visiting www.upe.ac.za/cerm
Quest 2(4) 2006 23
Left: A sapphire blowflyon a bush near a carcass. The stains on the leaves are from flies that have been feeding fluids from the carcass. If the animal dies of anthrax, these stains can spread anthrax spores to other browsing animals that eat the leaves. The stains are a good indication that a body was in the area, even if it has been removed by poachers or scavengers. The scientific name for blowflies ((Calliphoridae Calliphoridae)) means Calliphoridae 'beautiful flies', but probably applies to their colours rather than their habits!
How do bugs and insects help forensic entomologists to settle disputes and solve crimes? Martin Villet and Nikite Muller explain.
The six-legged flying squad T
here’s a new flying squad helping the South African police. That familiar nuisance, the blowfly or ‘brommer’, is rapidly becoming the mascot, like the fruitfly to genetics, of an international scientific discipline: forensic entomology. The public’s fascination with forensic entomology has grown over the last couple of decades in step with
Above: Studying the effects of different levels of dissolved magnesium sulphate on stream-dwelling insects. Results from such experiments, conducted under standardized laboratory conditions, help forensic entomologists to decide if a river has been polluted illegally by using the behavioural responses of the insects in the river as a guide.
24 Quest 2(4) 2006
its increasing prominence in popular culture. From cameo appearances in the movie Silence of the Lambs, the discipline moved to more central roles in The Body Farm and Blowfly, and now has regular ‘guest’ appearances in television crime dramas like Clancey and CSI. Scientists are not distant from these trends, and the attention directed towards forensic entomology is increasing worldwide. South Africa’s high rate of murders, including serial killings, has brought urgency to this research. The country has its own forensic entomologists and, in two recent Supreme Court murder cases, entomological evidence was taken into account to assist in the judgements. School-leavers are beginning to ask about careers in forensic entomology: what would they be letting themselves in for? Parents may be relieved to know there’s more to it than crime novelist Patricia Cornwell has let on. What is forensic entomology? Forensic science is a discipline that deals with expert scientific evidence relevant to legal cases. It ranges from the more familiar topics of ballistics and blood-stain analysis to esoteric specialities like pigment analysis and forensic botany. Forensic entomology concerns legal evidence provided by insects.
Just as law is concerned not only with murders, forensic entomology is broad in scope. In fact, it can be subdivided into four arenas: medico-legal forensic entomology is the one most familiar to the public, while urban, storedproduct, and environmental forensic entomology form the other specialities. This classification is based on the communities of insects that are typically involved, but also tends to reflect the branches of law and the types of client that a forensic entomologist encounters. Although the distinctions are somewhat artificial, they help to outline the diverse scope of this kind of work. Urban forensic entomology
This branch of the discipline is broadly concerned with insects around people’s homes, and usually relates to issues governed by common law or civil law, so the clients are generally private individuals and small businesses. The overwhelming majority of insects in these cases are fly-by-night pests like borer beetles, termites, cockroaches, and mosquitoes, and the subject of the associated litigation might be the competence of fumigation companies and the sanitary practices of livestock owners. Do the swarms of flies around your house really come from the new horse stud down the road? If the fumigators were right about treating your house
for fleas, why are you still getting bites? How reliable is the Borer Certificate for the house you’re thinking of buying? Entomological evidence for the most part allows these concerns to be settled out of court. An unusual case in this field comes from Norway and is known as “The Case of the Cleaning Woman”. One morning, a government official found some large maggots on his office carpet. He summoned the cleaning woman who cleaned his office each night and accused her of neglecting her job, which she denied. Reasoning that such large maggots could not have developed since the previous evening, he concluded that she was lying and had her dismissed. A veterinary inspector working in the same building heard of the events and asked to see the maggots. He concluded that they were mature larvae of a greenbottle fly, and that they had migrated to the office from a dead animal, perhaps a rat, that had died in some other part of the building. Without such food, they certainly could not have developed where they were found – and its presence would have been obvious from the smell if it had been in the office. The evidence corroborated the cleaning woman’s claims, and she was reinstated without the need for a court hearing. Stored-product forensic entomology
Medico-legal forensic entomology
This field can be subdivided on the basis of whether civil or criminal law is relevant. Civil cases may include medical and veterinary malpractice as well as neglect by care-givers of children and the aged, who may acquire infestations through negligence. The civil clients are usually private persons, and the insects are generally blowflies and fleshflies. Some cases may not even involve insects, however. Psychological cases of delusory parasitosis are sometimes brought to entomologists to deal with. These are cases where people are convinced they are infested with parasitic insects that no one else can detect. It takes careful entomological analysis to distinguish between illusory parasitosis (that is, imaginary parasitic infestations), entomophobia (fear of insects), and genuine infestations by various mites living in hair follicles and the epidermis. The legal issue here is whether the person has a psychosis that requires commitment to an institution, or whether the medical profession has been incompetent in seeking the parasite. An entomologist can help to make this decision. Where criminal law is pertinent, the discipline is distinguished as medico-criminal forensic entomology, which is the high-profile subject of public awareness. The client group encompasses accused criminals and the State. The routine CSI (Crime Scene Insects) are blowflies, fleshflies, and certain beetles and moths because a death is most often involved. The deaths are usually of humans, but poaching and stock theft can be investigated by similar entomological methods. A less well-known component of this work is called forensic entomotoxicology, which relates to the detection of chemicals in corpses where insects as used as an investigative tool. Drugs and poisons affect the development and behaviours of insects and accumulate in their tissues, which can provide a rich source of evidence. ▲ ▲
This kind of forensic entomology relates to cases involving insects in stored products, such as food, woven materials, and timber. As in urban forensic entomology, the cases tend to fall under common or civil law and mostly concern pests, but the species are different, and the commercial interests are generally large companies rather than small businesses. The usual suspects are various grain-feeding beetles, clothes moths, and booklice. Questions regularly asked by the public are along the lines of “Was the worm I found in my chocolate there when I bought it?” and “Was my woollen Persian carpet infested with clothes moths in the factory?” These cases rarely go to court, but insurance claims regarding infested or damaged consignments of valuable goods may warrant the involvement of lawyers and even magistrates. A less run-of-the-mill case concerns the criminal investigation of an illegal stored product in New Zealand. Two consignments of cannabis were intercepted and yielded a rich sample of insects. By compiling details of the ecology and geographical distribution
of the wasps, ants, and beetles in the cannabis, investigators deduced that the crop was grown in a specific part of South-East Asia, in fields near a water body in a hilly area, and then hidden for a while in termite mounds. The details were sufficiently accurate to persuade one of the suspects to grass on the others in the hope of a lighter sentence. This is a good example of the sort of puzzle-solving skills that forensic entomologists need.
Top: Martin Villet examines a rhinoceros that had died after being attacked by an elephant. An autopsy was performed on the carcass, which was soon covered in maggots. Their growth was studied so that the information could be used in future cases of poaching to determine an animal’s time of death. Middle: A technician monitors insect cultures for indications of poor water quality in the responses of insects in the laboratory. Below: Environmental toxicologists collect samples of insects from a stream to assess the health of the water.
Quest 2(4) 2006 25
Investigating death Death and the process of corpse decay
• time • manner
& Dry remains
Above: Maggots feeding on a dead warthog. Two species are present, differentiated by their colours. They have different habitat preferences on the carcass, which is why they are separated. This type of information can be useful in forensic investigations. ▲
For instance, the development of maggots allows the detection of cocaine in overdose cases, and toxicologists can detect heroin, barbiturates, organophosphates, and heavy metals in samples of maggots long after these chemicals can no longer be traced in the corpse itself. In South Africa, robbers used alcohol and sleeping pills to drug mineworkers on trains so that their pay packets could be stolen. Several mineworkers died from overdosing and their bodies were thrown from the trains to hide the crime, but the drugs were traced in samples of maggots, successfully linking the deaths to the investigation. Environmental forensic entomology
Here, insects are used to monitor the natural environment for evidence of pollution and undesirable change, and can provide evidence for both civil and criminal cases. This type of forensic entomology is still in the process of gaining recognition as a distinct discipline, and has gained increasing popularity in detecting effects of humans on the environment, either accidental or deliberate. In particular, the science of environmental toxicology For more about forensic entomology, visit the Science Careers.org web site http://sciencecareers.sciencemag.org/career_development/ previous_issues/articles/0000/forensic_science_resources_ for_making_the_transition;; the Southern African Forensic Entomology Research Laboratory at www.ru.ac.za/zoology/SAFER%20Lab/ www.ru.ac.za/zoology/SAFER%20Lab/; and the Unilever Centre for Environmental Water Quality at www.ru.ac. za/institutes/iwr/ucewq/.. You can find more details about the history of research in this field in southern Africa in K.A. Williams and M.H. Villet, “A history of southern African research relevant to forensic entomology”, South African Journal of Science,, vol. 102 (2006), pp.59–63.
26 Quest 2(4) 2006
• other insects • environmental details & conditions
The processes of forensic entomology help police with evidence when they investigate deaths that have occurred. Based on an understanding of the decaying processes of a corpse, and knowledge of the living organisms that invade a corpse, experts are able to estimate the conditions in which the person or animal died.
has won growing acceptance since the publication of Rachel Carson's landmark book Silent Spring in 1962. An example of an application in criminal law involves the South African National Water Act, which governs the management and use of freshwater resources. This act makes it illegal to dump waste into rivers at concentrations that affect organisms living in the water. Insects are used in laboratory experiments to set guidelines and environmentally safe thresholds for these concentrations, and their populations are monitored in rivers and streams to provide evidence of whether the water is being chemically insulted. Occasionally, industries release their toxic waste into a nearby river late at night, so that the flow of river water takes the waste downstream by sunrise and the industry can avoid spending enormous sums of money to convert their waste to an acceptable, environmentally safe level. But the abnormal community of insects and other invertebrates left living in the river can quickly reveal whether there has been an incident of ‘leaky valve’, although chemical analysis of the water might not indicate any problem. Insects can also accumulate pollutants in their bodies to detectable levels, even when the substances are too diluted to detect in the environment. Blowflies were used in this way to provide evidence of mercury pollution in Sweden. Although it has yet to become a legal issue, insects have also provided
Above: Collecting samples for analysis.
evidence of global climatic warming in Europe and North America. As average temperatures rise, butterflies that prefer warmer conditions have been found at higher altitudes and latitudes than before, and other insects that prefer cooler climates are also migrating to new localities. The field of forensic entomology is a fastgrowing one, with further applications being introduced and developed all the time. The six-legged flying squad is coming into its own. ■ Professor Villet heads the Southern African Forensic Entomology Research Laboratory at Rhodes University. Dr W.J. Muller is the Director of the Unilever Centre for Environmental Water Quality and specializes in environmental toxicology.
Q Careers in S&T
Work in forensic entomology F
orensic entomologists have two tasks: they develop sources of evidence through academic research, and they apply evidence in particular cases as expert witnesses. Being an expert witness does not necessarily mean appearing in court. In many civil cases where expert evidence is involved, the matter is settled out of court. In these instances, the evidence can have a direct bearing on whether the case needs to go to court. The same is true of criminal cases, but here an expert witness can have another role as well. As the investigation of the overdosed mineworkers in the article on page 24 illustrates, the forensic entomologist may, in some instances, not contribute direct evidence but rather uncover clues that lead the police to crucial discoveries. In either of these situations, it helps to be good at puzzlesolving. Jobs for forensic entomologists have been scarce throughout the world, but the situation is changing as the science grows. In South Africa, work as an expert witness in forensic entomology formed a component of a broader job in forensic science within the laboratories of the South African Police Service. Most other expert witnesses who provided entomological evidence to the South African legal system were employed in universities and other research institutions. But changes in the modern employment market are emphasizing self-employment and entrepreneurship, and the range of clients interested in forensic entomology is widening so much that a career as a forensic consultant is becoming feasible.
Career paths There are three ways to become a forensic entomologist in South Africa. ■ Obtain a university degree in science subjects including biology or chemistry, then join the South African Police Service and complete a broader training in forensic science in their laboratories. Afterwards, you could work for the State and you could specialize in entomological work that would be primarily medico-criminal.
■ Become a self-employed consultant in forensic entomology. The first step in this direction would be a university training in applied entomology, preferably with a specialization in forensic entomology at the level of Master of Science or even a doctorate. The next step is to find work in a mixture of urban, stored-product, medico-legal, and environmental cases for State, private, and commercial clients. A business-orientated way of thinking is a vital asset in taking the consultant route. ■ A third path lies between selfemployment and becoming a police scientist. It, too, entails university training in entomology or zoology, normally to the doctoral level, then joining a university or research institute and doing other things (such as teaching or research) in addition to forensic work. One can even specialize in research on forensic entomology, rather than undertaking case work. Obviously, as your career develops, you can move from one path to another. Each has its strengths: choosing the best one depends on an individual’s personal skills, interests, and personality.
Where to study In southern Africa, forensic entomology is offered as a module of the Entomology major at Rhodes University, while postgraduate specializations (at master’s and doctoral levels) are offered at the University of the Free State and Rhodes University. Forensic entomology is a fascinating subject and, far from being limited to solving murders, it can bring science to bear on a surprising array of commercial, social, and environmental problems. The growth of the subject throughout the world makes it international, while its expansion into new areas of law offers new scientific challenges to provide precise and legally reliable evidence. ■
Top: A research officer at the Unilever Centre for Environmental Water Quality tests water quality by examining insect cultures. Above: Insects on this lion’s skull give clues as to when the animal died. The beetles living on it indicate that the lion had been dead for more than six weeks. If this is a case of poaching, the information gives investigators a timeframe.
For details consult J. Ashcroft, D.J. Daniels, and S.V. Hart, Education and Training in Forensic Science: a guide for forensic science laboratories, educational institutions, and students. National Institute of Justice Special Report, US Department of Justice, Washington, DC, 2004. Available from www.ncjrs.gov/pdffiles1/nij/203099.pdf For a list of institutions abroad that offer training in forensic sciences, visit www.forensiccrimelab.com/training.htm For general information consult Careers in Science, Engineering & Technology (Beyond 2000 and Department of Science and Technology, 2006) and visit www.careersbeyond2000.co.za
The sexes are different Thousands of genes express differently in the sexes, reports Xia Yang, head of the research team at the University of California, Los Angeles, after his team had conducted comparisons in male and female mice. Over half the genes were different, he said, “an order of magnitude more than previously thought.” A total of 23 574 genes were profiled from 34 mice. Up to 70% of the genes in fat, liver, and muscle produced different amounts of protein in the two genders, as did 14% of the genes in brain tissue. The implications are that the mechanisms underlying many common diseases may differ between males and females, says Yang. Aspirin gives better protection against heart disease to men than to women, for instance, while the heart drug digitalis causes more deaths in women than in men. The reason could go deeper than just different drug metabolism in male and female livers, as was previously thought, and sex hormones are
Q News probably the key factor so all tissues are likely to be affected. Drug trials need to be gender-specific, Yang concludes. Reported from Genome Research in New Scientist (15 July 2006).
Scorpions help fight cancer Biotech company TransMolecular, in Cambridge, Massachusetts, says that venom from scorpions with a dose of radioactive iodine could help to treat brain cancer. A protein in the venom bonds to malignant cells, not to healthy ones, and this concentrates the radiation dosage in the tumour. Reported in New Scientist (1 July 2006).
Quest 2(4) 2006 27
Is the Solar System unique? Are there planets orbiting stars other than the Sun? John Menzies explains how South African astronomers have helped to discover the lowestmass extrasolar planet found so far.
ince at least the time of Aristotle, people have speculated about the existence of planets orbiting stars other than the Sun. Advances in our understanding of stars and their environments led to theories of planet formation but, with only the Solar System for comparison, they could not be tested adequately. Only in the past decade have we had the technology to investigate these questions scientifically. South African astronomers have been involved from the start and now they have helped to find the lowest-mass extrasolar planet discovered so far – after years of careful, patient observation and teamwork. The current view, supported by strong observational evidence, is that about 5% of Sun-like stars in our part of our own Galaxy (the Milky Way) have at least one planetary companion, and 155 such stars have been found. Most have a single planet, but the star 55 Cnc1 has four planets and a few others have three apiece. Most planetary systems Above: Artist’s impression of the newly-discovered planet, OGLE-2005-BLG-390Lb, with its parent red dwarf in the background. The red dwarf star has a surface temperature of about 3 500 °C and emits so little radiation that the distant planet would have a surface temperature of only –220 °C. The planet is about five times the mass of the Earth and is probably composed of rock with an icy surface coat. Picture: Courtesy of the European Southern Observatory
30 Quest 2(4) 2006
discovered till now are different from ours, but it’s too early to say whether our Solar System is atypical. What is a planet? A planet is a body that orbits our Sun or another star and does not give out its own light. It can consist of rock and metal (as do the inner planets of the Solar System, such as Mars or Venus) or mainly of liquid and gas (as do the giant outer planets, such as Jupiter or Neptune). Stars, such as the Sun, are much more massive than planets, and their gravity is strong enough to enable them to give out light by virtue of energy generated in their hot, dense, central regions through the conversion of hydrogen to helium in the process called nuclear fusion2. Some relative masses Earth Jupiter Neptune Sun
1 (Earth mass = 6 1024 kg) 318 17 332 776
First discoveries Astronomers are avid users of new technologies because they have so often yielded dramatic results. In the late 19th century, the old direct visual techniques were supplemented by photographic processes that could create images of star fields for archiving and for later measurement, which massively improved the efficiency of observation and increased the number of objects that could be studied. Comparing two images taken some time apart, for instance, allows the detection of very small motion of stars across the sky (that is, the proper motion). Advances in optics, the availability of telescopes with large collecting areas, and the steady increase in computing power led to the first detection, in 1995, of a planet orbiting a nearby Sunlike star, 51 Peg (in the constellation of Pegasus). The planet revealed its presence by disturbing its parent star’s radial velocity (that is, the speed of motion of the parent star along the line of sight from the Earth). The current
1. The 17th century, German lawyer and astronomer Johann Bayer catalogued the stars visible to the naked eye within each constellation, using Greek letters in order according to their apparent brightness (for example, Cen is the brightest star in the constellation Centaurus). For the fainter stars, the English astronomer John Flamsteed’s 18th-century catalogue is normally used. The stars in a particular constellation are given numbers in order of their positions around the sky (for example, 55 Cnc, the 55th brightest star in Cancer). New naming schemes have been adopted in modern times because so many stars have now been catalogued. So OGLE-BLG-2005-390Lb indicates the first planetary companion found associated with the object responsible for the 390th microlensing event detected by the OGLE collaboration in the Bulge in 2005. 2. Nuclear fusion takes place inside stars and is the process by which energy is released that makes the star shine. Two atomic nuclei of low atomic number fuse together to form a nucleus of higher atomic number, with the release of energy. The fusion occurs at high temperatures of the order of 108 K.
How astronomers find extrasolar planets
Gravitational microlensing is the reason that the image of a distant star brightens when a sufficiently large object (the ‘lens’), emitting little or no light – such as a planet – passes between the star and the observer. You’d expect that, if the two objects are exactly in line with each other, the nearer would simply obscure (darken, or occult) the other, but what we see is the opposite! That’s because the gravitational field of the ‘lens’ (the eclipsing object) bends the light beam from the distant star in the direction of the observer. (For an example of a stellar light curve illustrating this effect, see the graph on p. 33.)
now been detected for stars in the Large Magellanic Cloud and the central Bulge3 of our Galaxy. Because the stars in our Galaxy are all moving with respect to one another, a relatively nearby star occasionally moves in front of a more distant one. The light from the distant star is amplified (or magnified) – that is, the star seems brighter. As the foreground deflector moves in front of the background star, the observed brightness of the latter first increases, then reaches a peak, and after that declines to the original level. The closer the deflector is to the line of sight from the observer on Earth to the star, the greater the amplification. An observer refers to this variation as the ‘light curve’ of the source star (that is, the way in which the star’s brightness changes over time). Seeing the brightness vary, astronomers need to determine what’s causing the variation. Is this a variable star, whose brightness inherently varies all the time? Or is the variation in brightness the effect of gravitational microlensing? They use the nature of the light curve to help determine the cause. The precise shape of the light curve caused by microlensing is predicted by Einstein’s general relativity
* An arc second (arcsec) is an angular measure. The Moon has an apparent angular diameter of about 1 800 arcsecs.
equations. Einstein concluded in 1936 that the phenomenon was of no consequence since, even if one were to look in the direction of the centre of our own Galaxy where the star density is very high, the probability of observing it is only one in a million – in other words, an observer would
sensitivity with which radial velocity can be measured is such that we can now detect planets as small as Neptune orbiting Sun-like stars. Over 180 planets associated with 155 stars in our solar neighbourhood have now been discovered using this technique. Gravitational microlensing A century ago, Einstein predicted that matter, by virtue of its gravitational field, should have an influence on light. This was demonstrated experimentally by the English astrophysicist Arthur Eddington in 1919 when he observed the deflection of starlight near the limb of the Sun (that is, near the rim of its visible disk as seen from Earth) during a solar eclipse. When the object deflecting the light is very far away from us, its effect on light is described as ‘lensing’: we refer to ‘gravitational lensing’ when light rays are bent by the gravitational field of a massive object, such as a galaxy or a black hole. ‘Microlensing’ is what we call the effect when it occurs on a very small scale – for example, where light rays are bent by a single object whose gravitational field is far less strong – and this phenomenon is characterized by an apparent brightening of the background source. The effect has
Direct imaging – Planets shine only by reflecting light from their parent stars. This presents a severe problem for recording images of these objects because of the extreme contrast in brightness between them. Jupiter would appear to be only 10-9 times (one billionth) as bright visually as the Sun, if viewed from outside the Solar System. High-resolution imaging is needed because of the small apparent separation of the planet from its parent. This approach is technically difficult to apply from the ground, where the atmosphere blurs the image, and only one extrasolar planet has been imaged so far in this way. The chances of good-quality imaging are better from space, or in the infrared where the contrast is not so great. Four planets have been imaged so far using such techniques. Wobble detection – A planet orbiting a star makes the star seem to wobble backwards and forwards from the point of view of an observer. When the planetary orbit is seen edge-on, the star appears to approach and recede from us in a cyclical way and its radial velocity changes; if the orbit is viewed face-on, the star appears to move in a circle on the plane of the sky. About 180 planets have been found by astronomers measuring changes in radial velocity. Measuring the proper motion from the ground (or from Earth orbit) is extremely difficult, but future space missions (Gaia, SIM) will take on the task, unencumbered by the Earth’s atmosphere. Jupiter tugs the Sun’s position in space back and forth, making its radial velocity change by 13 centimetres per second. If the Solar System were viewed face-on from 30 light years away, the Sun would seem to move around a circle with an angular diameter of about 10-3 arcseconds. Wobble detection is therefore easiest for relatively massive planets orbiting close to the parent star. Transit – A planet that moves between its parent star and an observer on Earth blocks out some of the starlight, resulting in a slight apparent dimming of the star. For this to happen, the planet’s orbital plane must be within a few degrees of the line of sight to the star. Jupiter passing in front of the Sun, for instance, would reduce the Sun’s apparent brightness by 1%. This dimming is easily measured from the ground, and about 9 extrasolar planets have revealed their presence in this way. This detection method favours planets close to the parent star. Several projected space probes (e.g. COROT, Kepler) will search in this mode. Gravitational microlensing – The gravity of an astronomical object passing between an observer and a distant background star deflects the light from the star, which appears to grow brighter and then to return to its original brightness as the object moves across the line of sight. Four extrasolar planets have been detected by this method. This is the only way currently available of detecting low-mass planets.
3. The Bulge is the roughly spherical concentration of stars around the centre of the Galaxy.
Quest 2(4) 2006 31
to tell if a binary is responsible for a particular event. Consider a binary consisting of a star orbited by a (much lighter) planet: both bodies produce a microlensing effect, but the star’s lasts much longer than the planet’s because of the greater gravitational field of the star. In the direction of the Galactic Bulge of the Milky Way, microlensing events caused by stars typically last 20 to 60 days, whereas planetary perturbations (that is, small fluctuations) are around a few hours to two days in duration5.
Above: An image of the star field containing OGLE-2005-BLG-390. The high density of stars and their distribution are typical of those found in fields in the Galactic Bulge, only a few degrees from the Galactic Centre, observed by the PLANET collaboration. This picture combines three images (taken through blue, yellow, and red filters, respectively) and gives an impression of the predominant population of red giant stars in the region. The strong reddening of the starlight is caused by interstellar dust, which also obscures the light of distant stars, particularly on the left of the image. The blue stars are in front of the dust and are not reddened. There are upward of 5 000 measurable stars on this image: the brightnesses of all of them can be determined by computer in just a few minutes at the observing telescope. Figure: Courtesy of PLANET ▲
have to measure the brightness of a million stars at one time to have a chance of seeing even one star undergoing microlensing. New technology came to the rescue in the form of sensitive detectors4 for imaging, and increased computing power for measuring the brightnesses of many stars simultaneously in real time at the observing telescope. So, in the early 1990s, it became possible after all to perform the observations that Einstein had believed were not feasible. The first optical microlensing events were discovered in 1992 by the MACHO (MAssive Compact Halo Objects) group looking towards the Large Magellanic
Cloud, one of our nearest neighbours. These events are now being found at a rate of about 600 per year. Binary events The microlensing effect is more complicated when the deflector is made up of not just one but two objects orbiting one another in a binary system. About half of the stars in our Galaxy are one of a pair (called binaries). A bewildering array of light curve shapes is to be expected, given all the possible mass ratios and separations of the two objects as well as the range of possible angles of the trajectory of the background star with respect to the binary axis. But it’s generally easy
4. The detectors are charge-coupled devices, or CCDs. They are the electronic image detectors used in modern digital photography. 5. Lower-mass astronomical objects have more difficulty producing the high temperatures required for nuclear fusion, and a mass of about 13 times that of Jupiter is generally taken to be the upper limit for the mass of a planet. Above that size, the gravitational forces are great enough to trigger nuclear fusion in the core of a protostar (that is, a star in the earliest phase of its life, condensing out of a cloud of gas and dust, before the onset of nuclear burning). The ratio of the duration of a planetary perturbation to the total event time is proportional to the square root of the ratio of planetary mass to parent star mass.
32 Quest 2(4) 2006
A new planet found In 1995, the PLANET (Probing Lensing Anomalies NETwork) collaboration was formed, to monitor microlensing events closely so as to find out how many planets might be associated with distant stars in the direction of the Galactic Bulge. To do this effectively, our collaboration needed coverage 24 hours a day. This meant telescopes suitably spaced around the Earth – as an astronomical object sets at one location, dropping out of sight over the horizon, it rises at another about a third of the way further around the globe. PLANET uses telescopes in Australia (Hobart and Perth), South Africa (Sutherland and Bloemfontein), and Chile (La Silla), all in the southern hemisphere since the Galactic Centre passes almost directly overhead. They are of modest size, ranging from 1.5 m in Chile to 60 cm in Perth, but equipped with high-sensitivity CCD cameras and good computing facilities. The South African telescopes are at a vital longitude, filling the gap between Australia and South America. Data collected during the night are relayed to ‘homebase’, currently in Paris, and displayed on the Internet so that all the members of the collaboration can follow what is going on. Membership of the PLANET team has varied over the years, but currently stands at 30 astronomers from 9 different countries and 19 institutions. A Polish group, OGLE (Optical Gravitational Lensing Experiment), is dedicated to discovering microlensing events in progress, from data gathered by their 1.3-m telescope in Chile. They issue an alert to the astronomical community when a new one appears and, if it seems a suitable target, PLANET adds the object to the observing list. The OGLE team typically observes a given event once or twice a night, whereas PLANET attempts to
Finding extrasolar planets
The future Microlensing is the most efficient means of finding low-mass planets, but we need more observing stations and more frequent observations of events in progress. People get tired, don’t observe at the maximum possible speed, and take time off for meals. A network of robotic telescopes at good sites around the world, controlled by computers, would operate at maximum efficiency all the time.
Inside and outside the 1.0-m telescope at Sutherland, where microlensing work takes place. Above: The black box at the Cassegrain focus (to the right of the centre of the picture) supports the CCD camera that gathers the scientific images, and an autoguider that helps the telescope to track the target field accurately during a long exposure. The cryostat (foreground) contains liquid nitrogen, used to keep the camera detector cold so as to avoid electronic noise interference. Top right: The dome of the telescope, which protects the instruments against bad weather. The shutter is opened at night so that the telescope can observe the sky, and the louvres around the dome prevent excessive heating of the interior during the day.
RoboNet is a collaboration of United Kingdom universities with three 2-m telescopes (in Hawaii, La Palma, and Siding Spring in Australia) that can be commanded automatically to observe astronomical objects of interest. PLANET currently has a limited collaboration with RoboNet, which hopes to expand in the future to occupy more observing sites. Finding many more planets will give astronomers a clearer idea of the frequency of low-mass planets and will help to refine theories of planet formation and evolution. South African astronomers have helped to prepare the stage for these more ambitious projects and are all set to contribute further. ■ Dr Menzies is currently working at the South African Astronomical Observatory on the primary mirror system of the Southern African Large Telescope. He has been involved in PLANET science since its inception in 1995.
observe it at 1-hour intervals. On 11 July 2005, OGLE announced a microlensing event worth following. The light curve looked like a standard single-lens event and we had virtually given up on it by 10 August, when the observer at our telescope in Chile realized – just before the clouds brought observing to a halt for the night – that something unusual might be happening. He notified the Tasmanian and Perth observers. Hobart was under cloud, but fortunately the sky was clear in Perth, which meant that enough observations could be obtained to show, reliably, that we had found a new planet. By the time night fell in South Africa, the planetary event was over. Discovering our first extrasolar planet – carrying the unglamorous name of OGLE-2005-BLG-390Lb – had taken 10 years of patient observing, measurement, and analysis. Teamwork, good communications between observing sites, and the experience gained over time were vital to our final success. It was worth waiting for, since it turned out to be the lowest-mass planet associated with a star yet discovered by any technique. It is just 5.5 Earth masses and orbits its parent star in about 10 years at a distance of around 3 AU (astronomical units6). The light curve shows a small perturbation on the declining part of a normal single-lens curve. The parent star is probably a red dwarf, only one-fifth the mass of our Sun and about 20 000 light years away. A second low-mass planet of about 13 Earth masses, and two others of several Jupiter masses each, have been found by the effect of microlensing in the last two years. Since the probability of detecting a low-mass planet is far lower than the probability of detecting one as heavy as Jupiter, the current tally suggests that there are many more small ones than massive ones, and that extrasolar planets of a few Earth masses might be common.
3000 Danish Perth MOA
OGLE Robonet Canopus
JD – 2450000
The light curve of the microlensing event OGLE-2005-BLG390 showing the apparent brightness (on the y-axis) and time in days since JD* 2450000 (on the x-axis). The main curve is typical of that from an individual background source star and an individual or single lensing object. The inset at top left shows that the background star was of constant brightness over the preceding 4 years and became about 3 times brighter than normal at the peak around day 3583, while the inset at top right shows the planetary perturbation (or deviation) in detail. Different coloured symbols show data from different observing sites in the PLANET network as well as from other monitoring networks. The timescale of the main event was about 40 days, while the planetary deviation, which occurred during the night in Tasmania, lasted less than 24 hours and was all over by the time night fell in South Africa. Figure: Courtesy of PLANET * JD (Julian day number) indicates the number of days that have elapsed since mean noon (12 h UT) on 1 January, 4713 BC. The JD at 14:00 South African Standard Time (= 12:00 UT) on 1 January 2005 was 2453372.0.
For more, visit the Extrasolar Planets Encyclopedia at www.obspm. fr/encycl/encycl.html; the Wikipedia entry on microlensing at http://en.wikipedia.org/wiki/Microlensing; the PLANET public web site at http://planet.iap.fr; the MACHO public web site at www.macho.anu.edu.au/; the ESA Gaia Mission public web site at www.esa.int/science/gaia; and NASA’s Imagine web site at http://imagine.gsfc.nasa.gov/docs/features/news/ grav_lens.html. Read about the new discovery in J.P.Beaulieu et al., “Discovery of a cool planet of 5.5 Earth masses through gravitational microlensing”, Nature, vol. 439 (2006), p.437. For general information, consult Ian Ridpath (ed.), Oxford Dictionary of Astronomy (Oxford University Press, 2003).
6. An astronomical unit (AU) is the mean distance from the Earth to the Sun, that is, 150 million km.
Quest 2(4) 2006 33
Vision of quality Benito Khotseng suggests ways to turn South Africa’s schools round so that they provide quality education for learners countrywide.
the quality education essential for been achieved? chool systems differ. The building the infrastructure of modern Learners have turned to schools in performance of learners differs, society and for producing learners to large numbers since 1994 to improve as do incentives for working create and sustain the society that we their skills and their problem-solving hard; the availability of remedial desire. Yet schools in South Africa have know-how, but those schools keep instruction for slow learners differs, a high drop-out rate at primary and letting them down. Many learners as does the provision of enrichment secondary levels, and learners who fail – and schools (particularly those classes for outstanding scholars. have completed secondary education in poorer and rural communities) do Providing quality education lack basic competencies, which leads not provide much of what learners for all is a goal to which many in turn to high unemployment among need to be able to participate in what countries, including South Africa, the youth. J. Lee in 2001 called “the human have committed themselves. What The international community has conversation” – a metaphor for what do we need, in practice, to provide promulgated a set of millennium people think, do, feel, and express. primary and secondary education that development goals for primary and develops and guarantees acceptable secondary schooling, which is to be and minimum learning experiences for achieved by 2015. Yet primary and every learner, irrespective of gender, secondary education in rural and socio-economic status, or culture? low-income communities in A set of universally accepted The opportunity to South Africa remains far below core values typifies ‘quality’ standard. Drastic action is school education. They analyse and solve problems, needed. include offering learners prepare for life, and develop a sense the opportunity to collect, Fixing the problem at of independence and self-worth. analyse, and solve problems; schools to acquire and apply knowledge What can and must be done and skills that prepare them at school level to refashion and for life; and to develop a sense of revamp education so that it can start independence and self-worth. So there’s Such a conversation requires to approach the ideal? There are three much talk and effort around improving mastering knowledge as well as requirements: commitment, resources, the quality of learning and teaching. the reading, writing, and reckoning and the necessary machinery. skills through which people analyse, First, schools need teachers and What of South Africa’s communicate, and act productively. learners who are committed to their achievements? Yet our schools seem unable to instil work. The will to teach concerns Education improves people’s quality the competencies that form the basis and excites professionals involved in of life and reduces stressors such as for effective and innovative 21stquality education. For what is their diseases, poverty, and bad governance, century citizenship. responsibility if not to prepare the so the quest for quality schooling never Schools in rural and low-income next generation to be fit to do its job, ends. As South Africa puts twelve years communities still lack basic necessities whatever that job might be? of democracy behind it, we ask what such as sanitation, electricity, and An examination of government has been achieved, since the demise libraries. Township schools are schools that were shining examples of apartheid, in terms of the country’s overcrowded, with classroom and in their teaching, learning, and grade commitment to provide good school teacher shortages. The growing effect 12 external examination results1, education for all? of HIV/AIDS results in high levels of For many South Africans, the 1990s revealed that, even though some were teacher absence from school. remains the most significant decade in located in impoverished rural villages, If there’s a crisis in our schooling their history. Who can forget the miracle all had specific qualities in common. system, it is less because learners are of all South Africans voting together for Commitment to excellence by teachers not attending than because schools the first time in April 1994? After that, and learners always came first. The staff are not the ideal places in which a myriad of legislative changes were were driven by more than just earning to learn. Their inability to promote introduced to achieve equal schooling a salary. The search for excellence was innovative knowledge, life skills, and for all, to bring equity to the distribution articulated by both teachers and the problem-solving abilities has become of resources, to bridge the gap between school leadership as a guiding principle. a defining characteristic of rural, lowpoor and elite schools, and to achieve The school leadership, in turn, income, and township schools. many other goals. The result is one created an environment that All schools, regardless of their of the finest primary and secondary encouraged such commitment. The geographical location or the education systems – on paper. principal set an example of high communities they serve, should provide But has quality education for all standards to staff, and teachers set a
34 Quest 2(4) 2006
education for all similar example to learners. Leadership that’s based on being an example to followers creates a school climate in which, every day, quality is put into practice, upheld, and reinforced. In such conditions, teachers, learners, and newcomers to the school easily learn to understand, speak, and be led by the language of its goals. Second, the school itself needs to be a resource for providing quality education, creating the environment that promotes learning and innovation and that encourages teachers and learners always to try, even if they might fail. For E.A. Hanushek, for instance, this approach is essential for inspiring creativity as well as for attracting and retaining good teachers, as it enables everyone to learn, at every level of the institution. David Gavin defined a learning organization as one skilled at acquiring and transferring knowledge, and at modifying its behaviour to reflect new knowledge and insights. This means that a school must give teachers the time and resources to learn about what they do, and the flexibility to allow for change. Teachers’ attitudes, in turn, offer learners a sense of belonging and the security born of respect. In such an institution, learners are inspired to do better and to attain high standards of excellence in every part of their lives. Third, the ‘machinery’ for quality work is essential – that is, good leadership and action-orientated teams working together. Teachers at all the premier schools we examined worked in teams and supported each other. Activities that encouraged involvement were organized throughout the academic year. By approaching tasks collectively, teachers discovered what worked and what didn’t work – with the intention of using what worked to help them improve all the time. Such cooperation and teamwork encouraged teachers to take risks, be innovative, and not blame each other when things went wrong. They welcomed and embraced change because it helped them to produce quality work. They developed the courage to pursue personal learning and to sustain organizational commitment to quality education for all, regardless of the status of the
school. The road to success is not easy, but is accessible to every school. Taking national action Turning failing schools into successes needs support from the Department of Education, which should take three key steps to help build momentum for change.
The road to success is not easy, but it is accessible to every school.
First, the Department should declare publicly that learners admitted into high school need to graduate from grade 12 ready for work and college. School leaders and educators must then take responsibility for seeing to it that learners admitted at their schools graduate in the given time. Education officers need to advocate the policy that every learner should take subjects that will prepare him or her for life, because every learner can succeed and every learner deserves a chance. In short, the Department of Education and its schools must commit themselves not only to admitting learners but to graduating them adequately as well. Second, the Department should publish information about the move of learner groups from one class to the next, revealing it to parents, community members, and youth organizations. Such information should not remain private if a school is to improve. Communities need to know about failing schools. When they know the academic progress of learners at each school, they can recognize the extent of the problem and become part of the solution. Which schools are underperforming and why? Which schools are doing well? How can failing schools be helped? For communities actively to assist the Department in improving failing schools, they need information about those schools. The practice of having poorly performing schools in low-income and rural communities is so offensive to the idea of equal opportunity and equal
education for all that the only way it can be stopped is to expose it. All the people involved should be forced to confront this injustice; it cannot be left to teachers and the Department alone. Third, if it is true that all children can learn and that all schools must offer equal teaching and learning, then failing schools must be transformed. Turning such schools round needs strong intervention led by the Department and supported by the community, as well as by teams of experts with the power and resources to succeed. Community leaders and learners need to be trained in how to support such a turn-around. Finally, how can schools in lowincome and rural communities become learning organizations offering quality education? Teachers, community members, and the Department of Education need a shared understanding of precisely what is expected from each stakeholder to achieve such a goal. For any school to change, the people involved need to change. And change must start with the leaders, for they’re the ones who create the conditions that attract committed, open-minded teachers receptive to new ideas and processes. The leaders’ role is to promote quality teaching and learning as the key to quality schooling; what follows depends on the teachers, mirroring the values and behaviour of their leaders. With teacher commitment to good teaching and support to learners, learners can achieve, even in schools where educational resources are limited. ■ Professor Khotseng is Director of Batho Research and Development Consultancy and currently a visiting researcher at the Centre for Study of Higher Education at the University of the Western Cape. For more on the provision of quality education, read: A. Case and A. Deaton, “Schools’ input and Educational outcomes in South Africa”, Quarterly Journal of Economics vol. 114 (1999), no. 3, pp.1047–1084; D. Gavin, “Building a learning organization”, Harvard Business Review (July/Aug 1993), pp.78–91; J.D. Gilmore, School Performance Indicators in Developing Countries (Gilmore, Cape Town, 1997); E.A. Hanushek, “School Resources and Student Performance”, in G. Burtless (ed.), Does Money Matter? The effect of school resources on student achievement and adult auccess (The Brookings Institution, Washington, DC, 1996); T.J. Kane and D.O. Staiger, “Improving school accountability measures” (Working Paper 156, National Bureau of Economics Research, Cambridge, Ma.); and J. Lee and R.J. Barro, “Schooling quality in a cross-section of countries”, Economica vol. 68 (2001), pp.465–488.
1. These findings emerged from a 2004 small-scale pilot study conducted by Batho Consultancy among Free State high schools, in low-income communities, that had been producing good grade 12 results.
Quest 2(4) 2006 35
Rocks, mines, & daisies Read Earth’s history in the rocks of Barberton, revisit the gold rush, and enjoy the home of the internationally fashionable Barberton daisy, advises Sandy Ferrar.
o find occasional NASA researchers, international geologists, and a resident prostrate dwarf, go to Barberton, Mpumalanga. It’s also the setting of Bryce Courtenay’s novel The Power of One. Barberton’s scenic beauties have attracted visitors for decades, but it also has scientific interest if you know what to look for. Barberton and the Makhonjwa Mountains (also known as the Barberton Mountain Land) that enfold it are inextricably interconnected. Small, as mountain ranges go, the Makonjwas are deeply folded and peaked, a dramatic landscape with more than just visual impact. The region’s rocks offer the best-preserved example of the Earth’s ancient oceanic and continental crust, which formed between 3.6 and 3 billion years ago. Its remains remains have a distinctive green colour, and include some of the earliest forms of life on the planet (preserved as microfossils believed to be cyanobacteria). Here’s where researchers study Earth’s ancient crust, and there was no better place for NASA scientists to visit, to get to know the relics of the opening phases of life so as to recognize the same if they ever appeared in rocks retrieved from Mars.
Mineral wealth The rocks around present-day Barberton attracted all sorts of people long before aeronautics and space travel came on the scene. The Ngwenya iron-ore mine on the Swaziland side of the border is thought to be the oldest mine in the world, with radiocarbon dating indications that red oxides and shiny haematite for
early use as cosmetics were mined there between 41 000 and 36 000 BC. You’ll often hear the phrase ‘the oldest’ around the Makohnjwas as, dating from about 3.5 billion years ago, they are the world’s oldest leasttransformed rocks – they’re not older than rocks found elsewhere (such as in Australia, for instance, or Greenland) nor is this where life began, despite local advertisements calling this the “Cradle of Life”. They hold the best-preserved records of the earliest life forms, rather than proof that life began here. Yet the claim “oldest gold” might well be true, since it comes from the oldest bestpreserved rocks. The gold-mineralizing fluids are younger than the rocks, and their age of mineralization is around 3.1 billion years. (The goldbearing rocks on the Witwatersrand are around 2.8 billion years old.) Gold was the great attraction about a century and a half ago. The little mining camp around Rimers Creek, where the Barbers (Graham, plus cousins Fred and Harry) struck it rich in 1884, became for a while the centre of activity in the then Transvaal. This was the economic hub, the destination and departure point for transport wagons and coaches. The country’s first stock exchange was established here in 1886 and, in its heyday, Barberton had two of them. Today just a floodlit facade of the second one remains. Yet Sheba Mine (which produced the greatest tonnage of gold after Edwin Bray’s 1885 discovery of the reef,
Above: Barberton Daisy. Photograph: Cyclops Left: Gold-bearing ore. Photograph: Trevor Gibbons
resulting in Bray’s Golden Quarry) is still worked and is the world’s oldest operating gold mine. But free gold was mined out rapidly, and what’s left is refractory. Laced and threaded through the ancient Archaean Greenstone Belt1, the remnant gold is associated with pyrite and arsenopyrite and is retained in their crystal structure. The ore cannot be ground fine enough to extract the noble metal. The only way to get to it is to dissolve the rock. A process of biological extraction uses bacteria to oxidize sulphides to sulphates, and the iron from ferrous ions to ferric ions, and the compounds are made soluble, exposing the occluded gold (that is, the incorporated gold) for normal processing. This combination of biological and physical chemical processes has extended the life of the mines by increasing the yield substantially. African Pioneer Mining’s Agnes Mine uses a bioxidation heap process called Geocoat®, and Barberton Mine’s Fairview Mine uses the Biox® process developed by Gencor. Apart from Ghana (which applies them on a massive scale), Barberton is the only place in Africa where these processes are currently in use, making it a place of
1. The Archaean Eon is the period of Earth’s history extending from its formation, about 4 600 million years ago, to 2 500 million years ago.
36 Quest 2(4) 2006
Q The S&T tourist
interest for visiting biohydrometallurgists.
Plant life The slopes that wrap Barberton in mineralrich folds are covered by equally rich and varied plant life. Geology has a major influence on plant distribution and was used to refine the boundaries of centres of plant endemism2. You’ll see proteas, of which a few are very rare. The smallest and rarest of the endemic proteas is a dwarf prostrate shrub (Protea roupelliae subsp. Hamiltonii), with white flowers surrounded by delicate greenish-white bracts. It’s found only in a small area in Nelshoogte above Barberton, in leached-out soil, surrounded by glowering walls of pine. Threatening these little plants more than the steady march of pine boles are local bushbuck – the delicate dwarf protea is far less vulnerable since a fence was erected around the Dr Hamilton Protea Reserve. The prettiest rare protea is the Barberton Protea (Protea curvata), found on a few hills of serpentine rock, just north of the town. Standing about four metres high, the tree’s curved grey-green leaves and dark red bracts frame the thick mass of velvety, rose-pink flowers. Plants growing on serpentine rock are particularly interesting, since the rock is rich in metals such as nickel and chromium, which make the soil toxic. Some endemics to serpentines, such as Berkheya coddii, a daisy-like perennial herb with spine-tipped or bristly leaves, are able to absorb the toxic metals from the soil. This provides a double interest, in that they could be used in rehabilitating mine dumps, and there’s a suggestion of phytomining possibilities, where leaves might be harvested to extract the metals. Another aspect to Barberton Mountainlands’ botanical interest is that the deeply folded kloofs and gorges are self-protecting in their ruggedness, creating mini-environments protected from fire, harsh winds, people, and livestock. In one of these, the Ugutugulu Gorge, previously unrecorded plants have recently been discovered that are also found in the Nyika Plateau in Malawi and the Chirinda Forest of eastern Zimbabwe, for instance. Unrelated to the Barberton Centre of Endemism, these plants clearly indicate that the lost valleys house relic fragments of an extensive lowland forest, which existed when wetter conditions prevailed.
Further information Contact the following for information. ■ Barberton Mountainlands Geological Society have pamphlets on the Barberton Geological Heritage, the Bulembu Road Geotrail, the Fortuna Tunnel Trail, and Geology of the Kaapsehoop Trail. Contact: Chris Rippon (Chair), who says “Being a working geologist in Barberton is about as good as being a volcanologist in Hawaii!” at e-mail: email@example.com or tel. (013) 712 8500 during working hours. ■ Gerbera Society: Secretary Stephné Macaulay at e-mail: firstname.lastname@example.org ■ Lowveld Branch of the Botanical Society (Nelspruit): Chair, Guy Bagnall, at 083 455 4565 ■ Plant Specialist Group (Lydenburg): John Burrows, tel./fax (013) 235 3851 or e-mail: email@example.com ■ Barberton Bird Club: John Bunning at e-mail: firstname.lastname@example.org ■ Barberton Community Tourism: Astrid Christianson at e-mail: astrid@barberton. co.za or tel. (013) 712 2880 during working hours. For more details, read M.J. Viljoen and W.U. Reimold, An Introduction to South Africa’s Geological and Mining Heritage (Mintek, 1999); T. McCarthy and B. Rubidge, The Story of Earth and Life (Struik, 2005); S. Ferrar and T. Ferrar, Inside Mpumalanga: A guide for guides (Institute for Tourism and Leisure Studies, North West University, 2004); G.J. Campbell-Young and K. Balkwill, “Serpentines of the Barberton Greenstone Belt”, Veld and Flora, vol. 86(1), March 2000; J. Burrows and S. Burrows, “The Ugutugulu Gorge: A Botanical Time Warp”, PlantLife 31, Second Half 2004; and A.E. van Wyk and G. Smith, The Regions of Floristic Endemism in southern Africa, Umdaus, 2001); and articles in the serpentine ecology issue of the South African Journal of Science, vol. 97 (2001), no. 11/12 (Part 2). You’ll find more on geobiotics at www.miningweekly.co.za
Better-known is the fact that Barberton is the type locality of the Barberton daisy (the Gerbera, developed from Gerbera jamesonii), one of South Africa’s most internationally fashionable exports. Its spindly, petalled, long-stemmed, orange-red flower has been incorporated into the new Mpumalanga crest. Robert Jameson from Durban, who had a passion for indigenous plants, noticed it during the gold rush of the 1880s. He took samples to the curator of the Durban Botanical Garden, who cultivated them and sent specimens to London’s Kew Gardens. Botanists at the Cambridge Botanic Gardens developed hybrids and, within a couple of decades,
Opposite page (left): The Makhonjwa Mountains march into Barberton and embrace the little urban area. Photograph: John Dacombe
Opposite page (middle): Road-cutting, showing pillow lava near Msauli Mine on the eastern boundary of Songemvelo Nature Reserve. Viscous lava extruded into seawater, which chilled the surface of each pillow-shaped mass. Photograph: Chris Rippon
Opposite page (right): Spinifex-textured rocks are the oldest sea-floor komatiitic basalts dated at around 3.5 billion years ago. They indicate the high heat flow during the early formation of the Earth at around 1 600 °C, compared to modern basalts, which melt at around 1 200 °C. As the Earth is continuously cooling, these rocks are not found in younger rock sequences. They were discovered by South African geologist twins Morris and Richard Viljoen in the 1960s. Photograph: Chris Rippon
Above left: Just ten minutes’ drive out of Barberton, a view of the Barberton Mountainlands from the Bulembu Road, looking towards Sheba Mine. Mpumalanga Tourism has called this region “The Wild Frontier”. Photograph: John Dacombe
Above middle: A group of visitors enjoy the sweeping view across the Makhonjwas towards Mozambique. Photograph: Sandy Ferrar
Above right: The herringbone cross-bedding indicates tidal reversal captured in Moodies sediment of around 3.2 billion years ago, and shows that the Moon must have been in orbit early in the Earth's history. Photograph: Chris Rippon
the daisies were eagerly sought after by growers in the Netherlands, North America, and Australia. Despite the area’s unique riches, there are few organized or maintained trails or excursions, so special arrangements have to be made to visit the variety of rocks and botanical specialities. Barberton’s history is more easily accessible, with museums, guided walks through the town itself or down an early mine, and experiences of the basic technology of panning for gold. An organized quad-bike trail takes day-rides along the old wagon route to Sheba Mine, visits Bray’s Golden Quarry and the derelict boom town of Eureka, and offers sweeping views of Barberton Mountainlands swathed in abundant flora. ■ Sandy Dacombe Ferrar lives in Barberton. Best known for her work on Radio South Africa, in particular the programme “Talking of Nature”, she has authored two books and numerous magazine articles, both in South Africa and Malawi.
2. The Barberton Centre of Plant Endemism is an area of 3 988.4 km² and has a total species/taxa count of 2 210.
Quest 2(4) 2006 37
Q Your Q uest ions answered
QUESTION Is solar power really an option for generating the kind of electricity supply that the country needs? It can only be generated when the sun is shining, so we can’t use the excess when there’s no sunlight available – at night, for instance. It can surely only ever be seen as a back-up for more regular electricity supply methods, such as those from coal-powered stations or from nuclear power stations, which are able to generate electricity round the clock. ANSWER There are many ways of storing the energy converted from sunlight by a solar cell or panel. The most common method used is through batteries but there are many other storage methods. One of the most important features of solar power is simply not recognized by its opponents, sometimes because it threatens the commercial leverage that coal- and nuclear-based electrical utilities have over the consumer. What is that feature? It is that solar energy reaches all of the Earth's surface equally (according to geographical latitude). Therefore, Joe Soap in the middle of nowhere has as much access to it as Mr
Moneybags in the centre of a large city. None of the transmission and distribution networks that add hugely to the cost of grid-distributed electricity are needed when you use solar power. If I can make electrical energy available to myself from my rooftop, using a panel that delivers electrical energy at a cost of 20 cents (South African) per kW-h for the panel, plus a similar amount for storage and inversion to AC (alternating current), I might still find myself in a better position than the current city-dweller paying about 40 cents per kW-h1. Coal and nuclear power might be cheaper to produce at the station, but transmitting that power greatly inflates the cost.
QUESTION Solar panels require a great deal of space for practical implementation. Doesn’t this mean that they are a theoretical solution rather than a genuinely feasible one? ANSWER No, that’s not true. Two examples illustrate this. Suppose one fenced off the area enclosed by the towns of Upington, Pofadder, Calvinia, and Carnarvon in the Northern Cape. If solar panels with a mere 10% efficiency (the present commercial standard) covered this area, the sunlight collected over a year – taking account of night-time, cloudy weather, and the rise and fall of the Sun – would be sufficient for these panels to provide the current annual electricity consumption of the entire population of the world! Another example is closer to home. In the interests of safety, a region around the Koeberg power
station is kept clear of intensive urban development. A ‘limited development zone’ with a radius of 12 km around the power station has been defined. If this half-circle of land surrounding the station were to be covered by solar panels of 10% efficiency, they would provide almost 25% of South Africa's current electricity needs. In conjunction with Koeberg's nuclear power, a total of 32% of national electricity needs could be supplied by this small patch of land. So much for the claim that solar panels take up too much space! Answers from Dr Chris Engelbrecht, Department of Physics, University of Johannesburg
Send your questions to The Editor (write S&T QUESTION in the subject line) by e-mail to email@example.com OR by fax to (011) 673 3683. Please keep them as short as possible, and include your name and contact details. (We reserve the right to edit for length and clarity.) We will send you R80 for every question that is published with answers from our experts. 1. The South African figure of 20 cents per kW-h is the current production cost of the CIGS technology, patented by the University of Johannesburg and Vivian Alberts and described in Quest: 2(3), pp. 8–10.
Q News Day flights to reduce climate warming Fly by day to reduce the atmospheric warming caused by air traffic condensation trails (or contrails) is the message from researcher Nicola Stuber and her colleagues. Although the effects of contrails on climate are relatively small in comparison with those caused by other emissions, increasing air traffic makes it important to understand the phenomenon. Contrails produced by high-flying aircraft affect the Earth’s energy balance in a way that’s similar to the effect of high thin ice clouds, trapping outgoing longwave radiation from the Earth and atmosphere and reflecting incoming solar radiation. The net effect is warming. A study conducted over southeast England shows that the effect depends on
the time of day and season of the year. Contrails form in the wake of aircraft when the surrounding atmosphere is cold enough, and in ice-saturated regions they can exist for several hours. The results of the study were that, even though only 25% of flights occurred at night, they accounted for up to 80% of contrail warming, and that although only 22% of annual air traffic took place in winter, flights between December and February accounted for as much as half the year’s contrail warming. One way to minimize the climate effect of contrails is to change flight routes and/or cruising altitudes to avoid ice-supersaturated regions, the researchers say. Another is to shift air traffic from night-time to daytime. Reported in Nature (15 June 2006).
Quest 2(4) 2006 39
Right: Juvenile bateleur (Terathopius ecaudatus). The name that Levaillant gave this bird is still used because it evokes so well the eagle’s manner of flight. The long-tipped wings tilt this way and that continuously, making the bird seem an expert ‘juggler’ (bateleur). Illustrations courtesy of The Brenthurst Library, © The Brenthurst Press, 2004.
François Levaillant and the Birds of Africa. By L.C. Rookmaaker, P.J. Mundy, I.E. Glenn, and E.C. Spary (Johannesburg, The Brenthurst Press, Third Series, 2004). ISBN 0 909079 59 5 Reviewed by Alan Kemp
Observing African birds E
vents occur within particular contexts – geological, climatic, ecological, political, economic, social, and many others. Science too is influenced by context, no matter how hard scientists try to be impersonal, logical, and objective, so the history of science is important for understanding past factors that influenced our development of knowledge. This beautiful book about the celebrated 18th-century French scholar, traveller, and naturalist, François Levaillant (whose surname means ‘the brave’), shows all the quality of author selection, research support, and publishing skills that we expect from The Brenthurst Press. It is also a masterpiece for teaching and giving meaning to the history of science. Part One contains six chapters about the life and times of Levaillant, illuminated by a wonderful collection of pictures from a great variety of sources including the Le Vaillant Collection in South Africa’s Library of Parliament, and bringing to life the people, locations, lifestyle, and effects of Levaillant’s travels across the Cape Province from 1780 to 1784. Part Two, which contains the main subject of this book, presents some of the illustrations Above left: Fiscal shrike (Lanius collaris). The name that Levaillant gave this bird drew on its local Cape of Good Hope name, ‘fiskaal’. The bird’s colouring reflects the magistrate’s pied livery. Left: Red-necked falcon (Falco chicquera). Before Levaillant, nobody had described or illustrated this bird. In South Africa, it is found only in the Northern Cape, and Levaillant could have seen it at or near the Orange River.
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and texts that Levaillant prepared for his own opulent books describing his travels and studies of birds – works that attracted considerable attention at the time from explorers and scientists and that were translated and read in seven European languages. The 58 original watercolour paintings by Levaillant's artist Johann Reibold, mainly of predatory birds, that are reproduced in this volume belong to the Brenthurst Library and have never before been published. They served as the basis for the hand-coloured engravings that illustrated Levaillant’s own books, and the texts that accompanied each illustration in his publications have been specially translated here from the original French. Levaillant’s material is the basis for the well-informed, carefully researched, and at times humorous critique that Peter Mundy drafted about each of the bird species, examining the original plates and notes in the light of our current knowledge and their historical context. Many of Levaillant’s comments remain valid to this day. His skills as a taxidermist and as a field observer inspired him to present his specimens, mounted or illustrated, in a natural pose and within their normal habitat. Ian Glenn points out that birders today are often unaware of how novel it was at the time when, for instance, Levaillant positioned a bird in an active posture or portrayed a Common Fiscal with an insect impaled on a thorn nearby. Today, if we were to repeat Levaillant's travels from France via Cape Town to the limits of the Eastern and Northern Cape, we would plan for airline tickets, medical shots, first-aid supplies, 4×4 vehicles, trailers, camping gear, preserved foods, water treatments, binoculars, telescopes, laptops, palmtops, GPSs, field guides, maps, digital video, camera and sound equipment, mist nets, collecting guns, ammunition, deep freezers, and cylinders of liquid nitrogen to record, collect, and store our
Q Books Top left: This Couroucou Narina, a female Narina trogon (Apaloderma narina), was named after the Gonaqua girl whom Levaillant so admired that he called her Narina, the Khoekhoe word for ‘flower’. Top right: Klaas’s cuckoo (Chrysococcyx klaas), named to repay a debt of gratitude to Klaas, the man to whose valour Levaillant “more than once” had owed his “salvation”.
specimens. Among our concerns might be security of personnel, vehicles, and equipment along the way, uncertainty around the price of fuels, banking constraints on the issue and use of funds, obtaining the necessary documents and permits, or the influence of bird flu on the transport and shipment of our specimens. To say nothing of the laboratory, library, computing, statistical, and financial support that we would require to prepare and publish our results. Two centuries or so ago, the 27-yearold Levaillant used a more adventurous and entrepreneurial approach. He sailed for four months to reach Cape Town, dodged the effects of the Anglo-Dutch War but lost all his possessions soon after arrival, yet managed to journey on horseback and by wagon into the interior, bringing back the numerous natural history specimens that would establish his fame and fortune. His only equipment was a gun, and his main assets were enthusiasm for his subject, the ability to get along with people, the ambition to make a mark, and the courage, wit, and resilience to cope with the hardships he encountered in a very wild South Africa. On his return to Paris, his well-prepared specimens and his first-hand observations from a then unexplored part of the world allowed him to develop a market for his animals and, later, for his lectures, books, and knowledge. Fortuitously, his upbringing in Surinam in Guiana and life in the African wilderness accorded well with the tumultuous social and political reforms that were leading up to the French Revolution. If passion for one's subject is central to scientific success, it is ably demonstrated by Levaillant’s contributions. However, passion, or envy thereof, is also fuel for the national pride, personal insecurity, bureaucracy, jealousy, and other delusions that bedevil science and many of humankind's other endeavours. Levaillant carried out his investigations at a time in which scientific practice, the study of natural history, and systems for classifying and naming species were undergoing great change, and his work was dogged by controversy. He has been called a charlatan and accused of error, falsehood, and exaggeration. Yet there is no doubt that he pioneered the observation and documentation of South Africa's avifauna, published his results in detail, successfully used the latest preservation techniques for his mounted specimens and found secure homes for them. His complicated personal life, extensive family, financial problems, and the political upheavals of his time never dampened the enthusiasm and humour with which he approached the natural world, and he lived to the age of 71. Levaillant is regarded by admirers as the founder of African ornithology, and many of
the 134 valid southern African species in Oiseaux d’Afrique were unknown to science before their inclusion in his book. The Cape griffon, endemic to southern Africa, exemplifies his scientific legacy. His well-mounted type specimen, on which the first scientific description of the species was based, still survives in a European museum, as do many other of his specimens, and his descriptions of its biology, including its abundance on Table Mountain, remain original and important. At the same time, his humanity – shown in naming a cuckoo after Klaas, his Koekhoe companion, and a trogon after Narina, the beautiful Gonaqua maiden who took his fancy – may have been just as fundamental in securing his contemporary reputation and fortune. The multiple authors of the book under review bring considerable and diverse authority to the contexts in which Levaillant conducted his studies of the birds of southern Africa. Kees Rookmaker is a specialist in zoological history, Peter Mundy an ornithologist with considerable experience of the predatory birds (eagles, vultures, buzzards, falcons, owls, nightjars, shrikes, and bush shrikes) that are the subject of study, Ian Glenn an author and archivist with particular knowledge of European, American, and South African literature, and Emma Spary an editor and author deeply involved with French natural history and culture. This book stimulates the reader to consider and judge Levaillant’s contribution in the context of its time – and to consider the bearing that our own context has on the way in which we live and work. It provides an intelligent, attractive, and enjoyable account of one of the earliest and most important contributors to the natural history of South Africa, and will be read with pleasure by natural scientists, historians, ornithologists, and anyone interested in the birds of our region. ■ Ornithologist and naturalist Dr Kemp has many publications to his name, including Sasol Birds of Prey of Africa and its Islands (New Holland Publishers, 1998).
Above: Black-banded owl (Strix huhula). Levaillant accurately described this South American forestdwelling owl that hunts during the day as “closer to the diurnal birds of prey than to the African owl I have called Choucouhou.”
QUEST readers can receive a 10% discount on the book, as well as sets of bird plates reproduced from it, if they buy directly from The Brenthurst Press, PO Box 87184, Houghton 2041. Tel. (011) 646 6024; fax (011) 486 1651; e-mail: firstname.lastname@example.org
Quest 2(4) 2006 41
Caring for the Karoo Karoo Veld: Ecology and Management. Edited by Karen J. Esler, Sue J. Milton, and W. Richard J. Dean (Pretoria: Briza Publications, 2006). ISBN 1 875093 52 4
Main photograph: Warm north slope of a koppie with many noors plants. Top: Leopard tortoise. Above: Palatable bossies and opslag flowering abundantly in a road verge.
42 Quest 2(4) 2006
he harsh, unpredictable, wild, open Karoo landscape of rugged mountains, stony plains, salt pans, and sand dunes is the subject of this beautifully presented book. The area spreads over some two-thirds of South Africa, and its ecosystem is composed of land users and their livestock as well as wild mammals, birds, invertebrates, plants, and soil. All these affect and interact with one another – and are subject to the great fluctuations of rainfall and temperature, from year to year and decade to decade. This volume covers the five different types of Karoo veld ecology and is a practical, affordable guide to ways in which the region’s natural resources can be understood and managed, so that it can sustain not only commercial enterprises (such as wool and mohair production, mutton, game, and tourism) but also the life of the veld itself. Part 1 introduces the Karoo’s plants, animals, soils, and water resources; the influences of climate, soil, and management on veld composition; and the functioning and long-term value of the land. In Milton’s words, it shows how “natural Karoo ecosystems work, including the way plants grow and flower after rain then lie dormant, the importance of insects for pollination, the role of animals in making micro-sites for seed germination. Most important, it describes the limits imposed on land production, and hence on
animal numbers, by the low and variable rainfall.” “The second section deals with practical management issues, including grazing systems, water point arrangement, and veld and wetland rehabilitation”, she continues. It is based on the philosophy that land users should leave the land in as good or in a better state than they found it. Part 3 shows readers how to keep records, assess, and monitor the condition of the veld so that the quality of the land keeps improving – together with the efficiency (and the profits) of those who work it. Says Milton, “it requires the manager to examine carefully the composition of vegetation cover, the condition of individual plants, the establishment of various kinds of seedlings, and the animal activity on the soil surface.” The appendices in Part 4 are invaluable for those living in and visiting the Karoo who wish to learn, know, and appreciate its richness, diversity, and way of life: there are animal unit conversions, palatability and grazing indices for assessing the productivity of the flora, a splendidly illustrated guide for identifying different types of common Karoo plants, and an extensive reference list for further reading. An earlier, shorter publication – written by Sue Milton and Richard Dean in just a few months and published by the Agricultural Research Council (ARC) – appeared in 1996, “to put the understanding of Karoo veld ecology and management, which we had gained from research and interactions
Q Books New books Gough Island: A Natural History. By Christine Hänel, Steven Chown, and Kevin Gaston. (SUN Press, 2005). ISBN 1 920109 03 X Superbly illustrated, this book is about the animals and plants of Gough Island and gives a history of the territory’s discovery and exploration. It’s a must for island and seabird enthusiasts as well as for anyone concerned with biodiversity and its conservation in remote locations. Amazing Numbers in Biology. By Rainer Flindt (Springer, 2006). ISBN 3 540301 46 1 Did you know that the eyeball of a giant squid is nearly half a metre in diameter or that midges beat their wings more than 1 000 times a second? You’ll find wonderful statistics on every page of this splendid book.
Above: Opslag, grasses, and kapokbos seedlings.
Stapeliads of Southern Africa and Madagascar. Vol. I and II. By Peter V. Bruyns. (Umdaus Press, 2005). ISBN 1 919766 37 5 and 1 916766 38 3
Right: Tank waterpoint with a stone ramp and emergent plants. Below: Tree in standing water near Beaufort West.
with farmers, into a form accessible and useful to them”, explains Milton. “Roger Ellis [ARC Range and Forage Institute] had identified user-friendly, non-prescriptive information on Karoo rangelands and their management as a need in the agricultural community.” That concept and content gave the two authors the confidence to produce a fuller picture. Dean calls it “a ‘self-reinforcing’ project – the more we gathered together for the book, the more confident we felt about publishing it.” Then Karen Esler came on board; she involved additional specialists, raised the necessary funds, and, with great efficiency and energy, coordinated the revision and expansion of the original work. To raise awareness of the Karoo among a far wider readership, she says, “we wanted a book with practical and accessible visual as well as verbal messages”. She sums up the hopes that drove this initiative: “The vast landscapes and uniquely southern African biodiversity of the region are entrenched in the hearts and heritage of so many of us, but we need to ensure sustainability into the future. The Karoo has its share of threats (overgrazing, invasive alien plants, climate change). My hope is that every farmer in the Karoo and every visitor will have access to this book and will buy into its principles, because hope lies in knowledge.” A great coup, she adds, was finding Piet Vorster and his wife Elsa, who “did a spectacular job translating the book into Afrikaans”. The response to the publication has already exceeded all expectations.
Lavishly illustrated with maps, line drawings, and photographs, these volumes deal with the 182 species of stapeliads found in southern Africa, all but a handful of which are endemic to the region. They will delight and inform botanists, specialist hobbyists, and everyone interested in these succulents. Grass Aloes in the South African Veld. By Charles Craib. (Umdaus Press, 2006). ISBN 1 919766 41 3 Grass aloes are mostly miniatures. They’re deciduous, found mainly in grasslands, and their growing pattern is aligned to the winter fire cycles of the veld. Their attractive flowers make them desirable, if difficult, to cultivate, but this book with its illustrations gives all the information that one might want about them. A Patented World? Privatization of Life and Knowledge. By Ana Agostina and Glenn Ashton (English edition). (Fanele, 2006). ISBN 1 77009 229 3
Financed by the Critical Ecosystem Partnership Fund, the project took about two years from start to finish, but it’s a culmination of far more time and effort than that. As Milton describes it, “the collections of photographs by a range of people represent many hundreds of thousands of kilometres of travelling in the Karoo over two decades. The information and pictures reflect 19 years (each) of research and life in the Karoo for Richard, Karen, and me. With other experienced researchers and consultants, I should think that there is at least a century of observation in the book.” This volume will enrich the library and the understanding of everyone who ever has anything to do with the Karoo, whether as a resident or as a visitor. ■
This collection of essays analyses the ownership of many of the world’s ideas and products. Amongst other things, it examines the patenting and use for private profit of genetically engineered crops, patented computer programmes, human cells, and biodiversity, molecules, and atoms. It’s controversial, but it deals with material that cannot be ignored. Molecular Gastronomy: Exploring the Science of Flavour. By Hervé This. (Columbia University Press, 2006). ISBN 0 231 13312 X If you take science, cooking, and good food seriously, this book is for you. Drawing on research in the chemistry, physics, and biology of food, it reexamines and debunks timehonoured dictums about cooking, discusses such matters as the physiology of flavour and how chewing affects food, and is full of practical tips about delectable cuisine.
Quest 2(4) 2006 43
Q Q uest crossword Don’t interrupt!
You’ll find most of the answers in our pages, so it helps to read the magazine before doing the puzzle. 1
6 7 8
10 12 13
19 20 21
Across 1 US space station (6)
6 A kind of bird or grumble (6)
2 Open landscape covering twothirds of South Africa (5)
7 A vector of bubonic plague (6)
3 Goat product (6)
8 Warm-blooded vertebrate, the female sectretes milk to feed young (6)
4 10 Down has 20 regular panels of which shape? (9)
9 Another name for brommer (7) 12 Arachnid with a sting in the tail (8) 14 Genus of land snail of Gondwanan origin (11) 15 Sheba Mine, the world's oldest for this metal (4) 17 Where Barberton’s found (10) 19 Open grassland in southern Africa (4) 21 Guineafowl is of this type (4) 22 Genus of lowveld daisy (7) 23 International collaboration monitoring events in the faroff Universe (6)
5 Our leading institute of biodiversity (5) 10 Buckminster designed one (8) 11 Study of the relations between organisms and their environment (7) 13 Taxonomic group of animals or plants containing one or more species (5) 16 Briefly, name given to a low-mass planet (4) 17 Larva of housefly (6) 18 Alternative form of DNA (6) 19 Pathogenic agent that replicates within host cells (5) 20 Bricks fired here (4)
24 Number of divisions in the Linnaean system (5)
How do you like the crossword puzzle? Was this one too difficult? Too easy? Just right? Would you like a more difficult puzzle as well (with a prize)? Fax The Editor at (011) 673 3683 or e-mail your comments to email@example.com (Mark your message CROSSWORD COMMENT.)
Interruptions are on the increase with e-mails, SMSs, voicemail, and cellphones part of everyday living. There’s a heavy price to pay for letting them take over. They steal time from other projects and make it hard to return to what you were doing, according to a study conducted by Gloria Mark’s team at the University of California, Irvine. They found that only 77% of interrupted work is resumed the same day, and it takes an average of 25 minutes and two intervening tasks to pick up where you left off. More than two hours of a working day can be taken up by interruptions, a survey by US information technology research firm Basex discovered earlier this year. Even work-related interruptions affect productivity, which cost the US economy an estimated $588 billion each year – 6.5 times as much as the estimated cost of back pain. In 2005, the Institute of Psychiatry in London found that being bombarded with e-mails and telephone calls has a greater effect on IQ than smoking marijuana. And psychiatrist Edward Hallowell, based in Sudbury, Massachusetts, reports an increase in the number of people claiming to have developed attention deficit disorder in adulthood. They complain of being too distracted, forgetful, disorganized, and impulsive to get things done – but find that the symptoms disappear when they go on holiday. Disruptive interruptions take many forms, according to Mark’s study. About half are self-generated – amongst others, leaving your desk (18%), e-mails and phone calls (12%), talking (7%). Half of the disruptions come from others – new e-mails account for 13%, a person arriving (21%), the phone ringing (9%), a call from a person at another desk (5%). Technology may be part of the problem, but some researchers believe that it can also be part of the solution. Future computer systems of the cybersecretary kind could screen and prioritize potential interruptions to help us to get on with the job. Microsoft has been designing a system called “Priorities” that analyses interruptions for salience and urgency, for instance, and sorts junk from the real thing. But there are things you can do yourself too, to boost productivity: ■ Get a bigger monitor ■ Use a “do not disturb” sign ■ Arrange your desk to face away from the flow of people ■ Stand up when you talk to someone who is interrupting your work ■ If an interruption could take more than 2 minutes, add it to your “to do” list and continue with what you were doing ■ Write down in a notebook what you were doing when you were interrupted to help you get back to the task more quickly ■ Cut 2 cm off the front legs of your visitor’s chair to discourage long visits. Other solutions include having more respect for your own time, saying ‘not now please’ (with a polite apology), offering to schedule a meeting – and turning off the e-mail and phone until you’re ready to be available again. From a report in New Scientist (24 June 2006).
How researchers spend their time Paperwork is taking over, suggests a survey of more than 6 000 US faculty members. The Federal Demonstration Partnership reports that 42% of ‘research time’ is spent doing administration; 4 hours a week could be saved if administrative help were available; and 10% of their research grant is what some scientists would be willing to pay for such help. Reported in Nature from Chronicle of Higher Education (13 July 2006).
Switch off in a storm Stop chatting on your cellphone if you’re caught in a thunderstorm, say doctors. A teenage girl struck by lighting while talking on her phone was left with a burst eardrum and brain damage, they report, and the cellphone made the injuries worse by directing the lightning current into her body. Paul Taylor, from the UK’s Meteorological Office in Exeter explains: “Lightning normally goes around the outside of your skin, but if you have something metal on your body it can cause of lot of damage.” People can get burns from keys, watches, and coins too. The chances of being struck by lightning in the UK are small, but Gauteng is renowned for its powerful lightning, so South Africans take note. Reported in New Scientist from the British Medical Journal (1 July 2006).
Perilous overconfidence Narcissism makes some people overly optimistic and aggressive, say researchers from Princeton University. Their study of 200 volunteers showed that those who were overconfident enough to make higher-than-average predictions of their successful performance in a wargame were more likely to make unprovoked attacks and less likely to win. Could there be a lesson here for the world’s warmongers? Reported in New Scientist from the Proceedings of the Royal Society (1 July 2006).
Quest 2(4) 2006 45
Letters to Science and creativity
hat a pleasure it was to stumble upon the latest copy of Quest (vol.2, no.3). Working in the creative marketing field for a publishing house as I do, we use social science as a base but derive our energy through creative diversions from the empirical. It was therefore a pleasure to see this lateral process advocated in several of your articles, for instance in Jonathan Jansen’s enlightening piece on embracing variance in scientific method as well as in Doug Wilson’s article where he daringly compares mathematics to creativity. Indeed, countless scientific breakthroughs have occurred through ‘eureka’ events and one might postulate a positive correlation between these and the waspish creative process that harnesses
the most delightful diversions known to man – elaboration, originality, resistance to closure (that is, leaping beyond the obvious first response), and abstraction. Consider the wisdom of two creative scientists who embraced such processes: the fecund Thomas Edison who held some 1 300 patents, and the arch-maverick Einstein, who declared: “Imagination is more important than knowledge” and who also described the “mysterious” as the most beautiful experience, being the source of all true art and science. Your magazine is super. I wish you much luck in reaching readers – and, more especially, in bridging the gap between pure science and creativity. Philip Bateman, Kenilworth, Cape Town
Table Mountain in the sky
has been providing readers with loads of information about our extraordinary SALT telescope and the clear views we are often fortunate to have of our star-laden southern skies. And in these skies there seems always to have been something to observe and to feel special about. In 1750 (about a hundred years after Van Riebeeck landed at the Cape), the French mathematician and astronomer Nicolas Louis de la Caille (or Lacaille), arrived at the Cape as head of an expedition, which remained here for four years. Within two years he had determined and described the positions of nearly 10 000 stars in the less well known southern skies – he must have been starry-eyed! He also identified and named about 14 smaller constellations, among them one he named ‘Mensa’ for Table Mountain (from the Latin for table) – some sources give the name as Mons Mensa (or, mountain table). uest
What is so special, it appears, is that this is the only constellation in all of our skies, northern or southern, to bear the name of a topographic feature of our planet – and, at that, of our own Table Mountain. This faint constellation contains part of the Large Magellanic Cloud. One foot of the Mons is actually in this Cloud. To find the position of the Cloud, lengthen the long axis of the Southern Cross about four-anda-half times to reach the South Pole of the sky, then, pretending that you are on this lengthened line and facing the South Pole, draw a line 90° to your left and about half as long as the line from the Cross to the Pole. In this vicinity we must find Mensa. I’ve never seen a clear photograph of these stars that also gives a simple sketch of the Mons on it. Do any of your readers have such a picture and sketch that could be reproduced in Quest ? Liesel Smith, Murrayfield, Pretoria
The best letter from a reader published in the next issue will win a Shaeffer pen. Address your letters to The Editor and fax them to (011) 673 3683 or e-mail them to firstname.lastname@example.org (Please keep letters as short as possible. We reserve the right to edit for length and clarity.)
Q ASSAf News
New home for ASSAf The Academy has moved to its new offices in the recently completed building of the Department of Science and Technology (DST). It will gain immeasurably from its new position, in close touch with important sectors of the DST and in the same office area as the National Advisory Council on Innovation. It will also benefit from proximity to other centres in the vicinity – the National Research Foundation, the Council for Scientific and Industrial Research, and the Innovation Hub. Until further notice, the ASSAf’s multidisciplinary science journal, the South African Journal of Science, remains in its current offices. • The ASSAf’s new physical address is: The New DST Building, CSIR Campus, Building 53, South Gate, 1st Floor, Block C, Meiring Naudé Road, Brummeria.
science teaching in Africa, it was decided to hold a follow-up workshop to discuss the development of voluntary content tests for science teachers, on completion of which a certificate would be awarded. With financial support from the IAP and ASSAf, the workshop was held in Pretoria in March 2006 to begin the process of conceptualizing science content tests for science teachers in Africa. The focus was on senior secondary teachers in the areas of mathematics, biology, physics, and chemistry. The Global Water Programme has aroused interest among some 40 academies, and the ASSAf is involved through a three-day workshop being organized on its behalf by the Water Research Commission from 16–18 August 2006. The objective is to bring together researchers and managers in the field of water to discuss and offer solutions to the problems that Africa faces.
Research journals examined
The InterAcademy Panel (IAP) operates multinational programmes involving national academies from various countries. The ASSAf has taken an active part in two in particular: the IAP Science Education and the Global Water Programme for 2006. At a symposium in Dakar in 2005 on improving
As part of a contract with the DST, the ASSAf undertook a major study of South African research publications. There were two main points of departure. The first was that science publishing should take place inside South Africa on a significant scale because of its beneficial effects on
For young scientists countrywide
Prizes include cash, publication of the article in the Saturday Star, and a trip to the American Association for the Advancement of Science’s meeting in San Francisco in February 2007. Closing date: 31 August. For details e-mail email@example.com, fax (012) 320 7803, or visit www.saasta.ac.za/sciencewriters
■ Junior Science Academy Science Challenge (12 August) in Pietermaritzburg For details contact Mr Mnguni, Junior Science Academy, at: cell 084 837 4423 / 082 748 7964, e-mail firstname.lastname@example.org or email@example.com ■ National Mathematics Week (4–8 September) and South African Maths Olympiad (7 September) For details contact Ms Ellie Olivier, the S.A. Mathematics Foundation, at: tel. (012) 392 9323, e-mail firstname.lastname@example.org ■ Interprovincial Mathematics Olympiad (16 September) at centres across South Africa For details contact Dr Peter Dankelmann, School of Mathematical Sciences, University of KwaZulu-Natal, at: tel. (031) 260 3000, e-mail email@example.com ■ Eskom Expo for Young Scientists (28–30 September) in Gauteng and First African Science Fair (27 August–2 September) in Namibia For details contact Mrs Priscilla Moodley, Expo for Young Scientists, at: tel. (011) 894 1365, e-mail firstname.lastname@example.org ■ DST Maths and Science Educator Camps to support STEM (Science, Technology, Engineering, and Mathematics) Olympiads and Competitions (September 2006) in Mpumalanga, the Eastern Cape, and North West Province For details contact Mrs Nirvashnee Seetal, Department of Science and Technology, at: tel. (012) 843 6881, e-mail email@example.com
Young science writers’ competition The Saturday Star and the South African Agency for Science and Technology Advancement (SAASTA) are holding the second round of their Young Science Writers’ competition. Scientists aged 20–35 years at South African higher education institutions and science councils are invited to write a 700word article in plain English on a scientific subject.
Insite 2006 (24–27 September) South Africa’s second International Science, Innovation and Technology Exhibition (Insite) at the Sandton Convention Centre, Johannesburg, will showcase cutting-edge and enabling technologies aimed at improving the growing climate of innovation. Hosted by the Department of Science and Technology, Insite 2006 is directed towards the scientific community, local and international business, academics, the public, and students. The theme is the role of science, technology, and innovation in driving economic growth and development and improving quality of life, examined in relation to the government’s Accelerated and Shared Growth Initiative for South Africa (Asgi-SA). Insite 2006 addresses the youth and the skills shortage in science and engineering, strategic economic sectors, and sustainable development. Events include a conference, briefings, functions, and the Tobias Lecture. For details visit www.dst.gov.za/insite> Insite 2006
Oceans in space The new Iziko Planetarium show in Cape Town, “Oceans in Space”, was inspired partly by NASA’s Origins programme, which aims to discover if anyone beyond the bounds of Earth is out there. The show also takes visitors 5 billion years back in time to trace the origin and evolution of our Solar System so as to understand more about where life could have begun. The show opens on 12 August and runs daily. For details phone (021) 481 3900.
research conducted in the country; the second was that local publications should be of high quality. Of the ten recommendations made in the report, two are ready to be taken further. Recommendation No. 3 is that the ‘best practice’ guidelines proposed in the report be widely discussed under the aegis of the Academy before being formulated and publicly adopted by South African editors and publishers of research journals. Recommendation No. 7 is that a ‘national research publications information and research centre’ be formed, to gather and analyse information about South African journals as well as publications in foreign journals emanating from authors working in South Africa. The discussion process is beginning. The report has been formally presented to the departments of Science and Technology and of Education and responses are to follow. For the full report visit www.assaf.co.za Righting wrongs A couple of errors slipped into Quest vol. 2. In 2(1), p. 29, Professor Anusuya Chinsamy-Turan was wrongly described as a palaeobotanist: she is in fact a palaeobiologist. In the same issue, on p. 42, the photograph was incorrectly attributed to Morris Viljoen; the credit belongs to the Struik image library (Images of Africa). We apologize.
Q Diary of events The Pathway to Humanity – a female perspective (August–September) At Maropeng (in conjunction with Palaeoanthropological Scientific Trust) in the Cradle of Humankind, a series of talks will be presented from 5 August to 2 September by women in the South African scientific community. Topics include archaeology, genetics, palaeoanthropology, women in prehistory, and the way forward for the next generation of scientists. The lectures are free of charge to the public, but booking is essential as space is limited. For details phone (014) 577 9000, fax (014) 577 9500, e-mail firstname.lastname@example.org, and visit www.discover-yourself.co.za
Structural Biology Conference (24–27 October) The First African Structural Biology (FASB) conference will be held in The Wilderness. It focuses on the contributions and potential contributions of structural biology to the development of science and wealth creation in Africa, with some emphasis on biotechnology and the alleviation of the continent’s disease burden, in particular tuberculosis, AIDS, and malaria. Due date for abstracts: 31 August 2006. For details and registration visit http://sbio.uct.ac.za/conference
Plan for ■ Biosciences month (August) ■ African Origins month (September) For details phone (012) 843 6859.
Quest 2(4) 2006 47
Back page science Q Well said
Greener on the far side
■ “When you make the finding yourself – even if you're the last person on Earth to see the light – you’ll never forget it.” Astronomer Carl Sagan (1934–1996) ■ “There is no more difficult art to acquire than the art of observation, and for some people it is quite as difficult to record an observation in brief and plain language.” Professor of medicine William Osler (1849–1919) ■ “He seems to have an inordinate fondness for beetles.” Geneticist J.B.S. Haldane (1892– 1964), when asked late in life whether his studies had taught him anything about God. ■ “He who asks a question is a fool for five minutes; he who does not ask a question remains a fool forever.” Chinese proverb
A herbivorous dinosaur, Erketu ellisoni, which lived more than 100 million years ago in what is now the Gobi Desert, was mostly neck – more than seven metres, which was over half its full length. How did it get about without falling on its face? The secret was in its neck vertebrae, which were long but full of cavities and air sacs, reports the New York Times. This made them strong but very light.
It all depends A cartoon by Randy Glasbergen shows a teacher at a blackboard, on which is written: “The square root of 9 is 3. A) True. B) False. C) Who cares?” The caption: “Many students actually look forward to Mr Atwadder’s maths tests.”
Just one thing
More about knitting FactMonster reports that an oil spill near Phillip Island, Australia, in 2000 threatened the resident fairy penguins – the smallest species of penguin. Rescue workers found that the best way to keep the penguins warm and prevent them from swallowing oil while preening was to dress them in dolls’ jerseys. Knitters around the world got going and the penguins ended up with more of the 23-cm × 10-cm pure wool sweaters than they needed. But they still had to hand them back before being released into the wild when they recovered.
I say, I say, I say The BBC reports that a rare species of frog, Amolops tormotus, is the first amphibian known to communicate using ultrasound. It may have evolved this mechanism to be heard above the sound of running water, as it lives next to fastflowing streams in China. There are frog species that have solved the noise problem in other ways, including waving brightly coloured feet.
The online publication Spiked surveyed more than 250 scientists and educators to find out what they would teach the world about science if they could choose just one thing. Many of them chose the scientific method or the theory of evolution by natural selection. Some chose basic principles in their own fields. Here are some other responses: ■ Simon Baron-Cohen: “I should teach the world that scientists fall in love — with experiments. An experiment can be beautifully stunning. Experiments are not just about proof – some of them have an intrinsic elegance that you just want to go back to and look at again and again.” ■ Sonja Boehmer-Christiansen: “Science, natural and social, is the only method we have for discovering – or at least approaching – truth, which is potentially accessible to all human beings. Without science, we would return to a state of being slaves of superstition – mere playthings of natural forces. We would also likely be more subject to exploitation.”
■ Brian J Ford: “By the age of 10, every child should have experienced the discovery of microbes. The sight of minute organisms swimming and moving under the microscope alters your life. Everyone should see living cells in childhood.” ■ Peter Marsh: “Science is not just something that boffins do. Central to all science is the notion of evidence, and objective reasoning. That has fundamental relevance to us all, and to the ways in which we choose to live our lives.” ■ Vivienne Parry: “You do not have to be bright to do science. If you follow the scientific method, then anyone can do it. Understanding this would break down the barriers that currently exist between nonscientists and scientists, and would – at a stroke – make science accessible to everyone.” ■ Jack Pridham: “Probability and risk, so that armed with the basics of statistics, the public would be able to challenge scary media reports.” ■ Gerardus 't Hooft: “I refuse to answer. This question brings me to despair. Is it really true that the world wants to hear only one thing about science? And then continue after that, with its ongoing religious, superstitious, and political disputes? There are thousands of essential things you need to know about science.” Answers to Crossword (page 45) ACROSS: 1 Skylab, 6 Grouse, 7 Rodent, 8 Mammal, 9 Blowfly, 12 Scorpion, 14 Prestonella, 15 Gold, 17 Mpumalanga, 19 Veld, 21 Game, 22 Gerbera, 23 PLANET, 24 Seven. DOWN: 2 Karoo, 3 Mohair, 4 Hexagonal, 5 SANBI, 10 Football, 11 Ecology, 13 Genus, 16 OGLE, 17 Maggot, 18 Allele, 19 Virus, 20 Kiln.
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48 Quest 2(4) 2006