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TABLE What is Extinction……………..........................3 Danger of Extinction.........................................6 Caring of Animals………………………………10 Wildlife & Pollution……………........................13 Climatic determinants of global patterns of biodiversity………………………...21



Extinction is an evolutive process that leads to the disappearance of a species or a population. When a species becomes extinct, its entire genetic heritage is lost for good. With evolution, a species can become another in order to adapt to the small environmental changes or due to casual changes in its genetic heritage. This process is known as speciation, in other words the birth of a new species. Speciation and extinction are both part of the natural evolutive process of living beings. Therefore, the natural extinction of a species in itself must not be interpreted as a negative event (nor, obviously, as a positive event), but it must be considered simply for what it is, in other words, an expression of biological evolution. The great extinctions in history, in fact, were accompanied by the formation of new species that have given continuity and vigour to the diversities of life. Normally two types of extinction may be classified. There is the background extinction that is the slow and, for us, imperceptible trend of the living creatures to transform constantly. And then there is the episodic extinction, with massive and concomitant deaths of species, triggered by rapid changes in the environment. In general, the extinctions that contributed most to the drastic changes in the flora and fauna in the earth’s history, were of the second type. Some extreme events took place on a vast scale during the course of the geological eras, like climate changes or the impact of our planet with comets and asteroids, which translated into environmental perturbations that were so radical that there were not many possibilities of escape for a multitude of organisms.


At various times of the Earth’s history, these phenomena have been very severe limiting factors for the survival of the species, and at times these have drastically cut biodiversity in entire geographic regions, causing the so-called mass extinctions. Paleontology experts have discovered five great mass extinctions in the last 500 million years. From the famous one that led to the extinction of all the dinosaurs on the Earth. During these great extinctions it is believed that 75 per cent to 95 per cent of the number of extinct species is believed to have gone lost. However, today the extinction rate is not considered natural, but the main cause of it all appears to be mankind, that, according to some scientists will cause a sixth mass extinction. In fact approximately 23 per cent of the Mammals and 12 per cent of the Birds are considered to be endangered by IUCN (the International Union for Conservation of Nature). There seem to be a number of causes that lead to this rapid mass extinction, however they are all caused by humans: constant growth of human population with a non-sustainable life-style increase in urban areas increase in the production of waste and polluting substances increase in alien, non autochthonous species climate changes international 4 conflicts

American origin, living from the jungles of Mexico up to the North-East of Argentina, approximately. They feed of insects and berries and live in the trees.

The otter of river or subtropical otter is a mammal that he lives along every amĂŠrica, specially in sylvan humid regions. In Colombia, this species is disappearing by leaps and bounds due to the destruction of his ecosystem.

The tortoise Carranchina is one of the species most threatened in the whole America. Her population does not overcome 1000 individuals in the departments of Cordova, Sucre and Bolivar, specially for the loss of her habitat and the accidental hunt in the Rivers of the Atlantic coast.

The Guasa or Guaza, is one of the big fish that live our coasts. He can live in sweet water but it is more common to find him in salty water with copies that overcome 200 kilos. This fish is on the verge of extinction basically for the indiscriminate fishing so much sports as of commercial character.


The Golden Frog of the Pacific Ocean is an amphibian that one finds in the Department of It hit specially and south part of Panama in the jungle of the Darien. At present this frog is considered to be the terrestrial vertebrate more poisonous of the world overcoming to the Asian, African and Australian serpents. Her survival like species meets threatened by the reduction of his habitat.

The Jaguar, also known as American tiger, takes Center as a habitat America from the south of the United States, happening for Mexico up to Argentina; it thinks nowadays that his number is near 6000 copies being one of the species near to disappearing.

The Sea-cow is the name more common that there is given he to this pretty species, so initially in 1850, one finds him in a municipality of Sea-cow in the department of the Atlantic Ocean. This placid vegetarian animal can live both in sweet water and in salty water.


The Condor of the Andes, it is the bird does not marinade, of major embergadura and size, lives along the mountain chain of the Andes, wherefrom his name comes in heights that it changes from the 1000 msnm up to the 5500 msnm. It estimates that this bird, of the family of the vultures, only comes to 6000 copies.

The deer of white tail also known as deer of white tail, it is a mammal that one finds in different types of forests of Canada, up to Bolivia, his size is average and normally it does not exceed 60 kg In Colombia this serf is almost extinct concentrating his population in Central America and Canada.


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Frequently, the animals are supported as domestic companions. While there are owners who deal with their pets since it is owed, many others suffer from inadequate care, They are careless and even of abandon. THE CARE BEGINS FOR HOUSE Your domestic animal must be:

· Frees of hunger and be. · Frees of inconvenience. · Frees of pain, injuries and diseases. · Frees of fear and pain. · Frees to express normal behavior.

THE CARE OF THE ANIMALS IS A RESPONSIBILITY OF ALL Denounce the cruelty towards the animals Learn to recognize the signs of abuse or carelessness. Identify the local institutions entrusted to receive reports of cruelty. 10

HELP TO REDUCE THE ANIMAL OVERCROWDING There are million dogs and not wished and street cats in the world. Insure itself of sterilizing to his pet and of chip identifying her with mike if it is possible. Adopt his near animal companion in a lodging or center of local rescue. THERE SUPPORTS THE INTERNATIONAL RECOGNITION OF THE IMPORTANCE OF THE ANIMAL Firm well-being the global request for a Universal Declaration on Animal Well-being. This agreement would give to the animals of all parts of the world the same basic levels of protection. Admitting that the cruelty can come from the ignorance, the WSPA works to improve the well-being of the animals with owner across education. Please help us to continue educating the owners of the animals and to carrying out other vital works of well-being. 11

Pollution is one of the primary ways in which humans have caused drastic modifications of wildlife habitat. Historically we have regarded the air, water, and soil that surround us as waste receptacles and have given little consideration to the ecological consequences of our actions. As a result, wildlife populations are confronted with a bewildering array of pollutants that we release into the environment either by intent or accident. In some cases wildlife populations have suffered severe losses or even faced extinction due to pollution. For example, the bald eagle, peregrine falcon, and brown pelican all nearly became extinct before scientists discovered that the synthetic chemical DDT was the cause of devastating reproductive failure in these species. Oil spills, such as the fouling of the coast of southern Alaska by the grounding of the Exxon Valdez, take an immediate toll on many species with the misfortune of living near such blunders. Toxic metals can kill adult members of wildlife populations and cause the production of deformed offspring, as seen at Kesterson Reservoir in the San Joaquin Valley. Acid rain has caused hundreds of fish populations to disappear from lakes in the northeastern U.S. and Scandinavia. In this chapter each of these notorious instances of the impacts of pollution on wildlife are described. The chapter also provides a general discussion of the origins and effects of synthetic chemicals, oil spills, toxic metals, and acid rain. 13

Pollution can be defined as the human alteration of chemical or physical characteristics of the environment to a degree that is harmful to living organisms. Some forms of pollution exert a destructive influence on wildlife by killing or impairing the health of individuals. Synthetic chemicals, oil, toxic metals, and acid rain are included in this category of toxic pollutants. Other forms of pollution affect wildlife in a more indirect manner by altering or destroying wildlife habitat. Examples include the obliteration of canyons, marshes, and grasslands with solid waste landfills; the destruction of the ozone layer by chlorofluorocarbons, which may lead to widespread damage due to the effects of excessive ultraviolet radiation on wildlife and their food sources; and carbon dioxide accumulation in the atmosphere, which may lead to global changes in climate and the distribution of wildlife habitats. Although both of these categories of pollutants pose significant threats to wildlife, this chapter focuses on toxic pollutants because of their specific effects on wildlife.


Modern society relies heavily on the use of fossil fuels (i.e., oil and coal) not only as a source of energy, but also as a raw material for many products, including synthetic chemicals, plastics, and Styrofoam. Fossil fuels are comprised primarily of compounds called "hydrocarbons." Hydrocarbons are molecules comprised largely, as their name suggests, of hydrogen and carbon. Hundreds of different hydrocarbon molecules exist due to variation in the number and arrangement of these atoms. Hydrocarbons yield large quantities of energy when they are burned. The most obvious effects of oil spills on wildlife are the deaths that occur immediately after the spill, due to coating of animal fur or feathers with oil and exposure to high concentrations of the toxic components of crude oil. These effects may be assessed by estimating the numbers of animals killed immediately following a spill. When birds and mammals become coated with oil, the insulating property of their feathers or fur is lost. Feathers and fur provide insulation by trapping a layer of air between the skin and the external environment. Oiling disrupts the arrangement of feathers and hair that retains this insulating layer. In arctic environments, the resulting hypothermia contributes to the death of many animals. 15

It is usually impossible to distinguish the effects of hypothermia from the effects of exposure to the toxic components of petroleum. Crude oil is a complex mixture of organic and inorganic chemicals that varies widely in its composition. Some types of hydrocarbons present in petroleum are toxic to wildlife, and direct exposure to crude oil can cause toxic effects. Oiled animals are exposed to acute doses of hydrocarbons absorbed through their skin, inhaled, or accidentally swallowed. Oiled animals also intentionally swallow the toxic material as they preen their bodies. Animals that are recovered and examined often suffer from a multitude of symptoms due to the inundation of their internal organs with toxic chemicals. The long-term effects of oil spills are far more subtle and difficult to assess than the short-term effects. The presence of persistent toxic chemicals on the beaches, in the water, and in the food web may result in a variety of impacts on wildlife, including impaired reproduction, decreased resistance to disease, anemia, eventual development of cancerous tissue growth (particularly in fish), neurological damage, and birth defects in offspring. The extent to which such effects occur in the years after an oil spill is largely unknown. 16

Toxic metals (Table 11.1) are natural components of the earth's crust found throughout the ecosphere in at least small (or "background") concentrations. These background concentrations are harmless to living organisms. Human activities, however, can cause concentrations of toxic metals to reach levels that pose hazards to living organisms. Some of these activities include burning of fossil fuels, metal refining, agriculture, mining operations, and wastewater discharge. For most of the toxic metals, the quantities of these substances mobilized by humans far outweigh the amounts that would naturally cycle through air, soil, and water of the earth (Nriagu and Pacyna 1988). Toxic metals are present in oil and coal, and metalcontaminated particles are released into the atmosphere by combustion of these fuels. Toxic metals are also released into the atmosphere by were emitted. A small fraction of these particles, however, becomes suspended in the upper atmosphere and is transported great distances from its source. As a consequence of this long-range transport, unnaturally high concentrations of toxic metals have been found in glaciers and lake sediments in the most remote regions of the Northern Hemisphere (Schindler 1988).



ACID RAIN Although acid rain presently is one of the most familiar forms of environmental pollution, the potential hazard posed by acid rain was first recognized only 20 years ago. By the late 1970s, public concern over the effects of acid rain on aquatic and terrestrial ecosystems had become widespread. At that time, some respected researchers still contended that there was no reason to believe that pollutants were the chief reason for acidification of surface waters. In order to settle this controversy, President Carter in 1980 initiated a 10-year program to study the causes and effects of acid deposition, and strategies for its control. The National Acid Precipitation Assessment Program (NAPAP) is presently drawing to a close after an expenditure of $500 million, making it one of the largest research efforts in history (many of the more than 1000 researchers employed through NAPAP will soon have to find a new line of work). The evidence is now thoroughly convincing that pollutants emitted during fossil fuel combustion are responsible for acidification of lakes and streams in the eastern United States.


Acid rain is primarily caused by the release of sulfur and nitrogen into the atmosphere as a result of the combustion of oil and coal by power plants and automobiles. Acid rain is actually only one of several ways in which the acidity of aquatic ecosystems can be increased. Acid snow and acid fog also have been shown to occur. Acidic particles suspended in the atmosphere and gaseous forms of acids (collectively referred to as dry deposition) are also known to contribute to acidification of surface waters. In the following discussion the term "acid rain" will refer to all of these various forms of unnaturally acidic deposition from the atmosphere. Acidification can also occur due to other sources, an important one being acid mine drainage. As the acidity in vulnerable water bodies increases, sensitive species of fish and other organisms begin to lose their ability to reproduce and survive. Juvenile fishes and many organisms lower in the aquatic food web are particularly sensitive to the effect of increasing acidity. The early disappearance of organisms eaten by large predatory fish is thought to a primary explanation for crashes in fish populations. Direct toxicity to adult and juvenile fish is another important factor in these declines. The toxic effect of acid rain on fish is due both to the acidity itself and to other substances (e.g., aluminum - some forms of which are toxic) that are formed or released under acidic conditions.


The number of species residing on spaceship Earth is staggering. Current estimates include over 4,600 species of mammals, about 9,000 birds, over 6,000 reptiles, more than 4,000 amphibians, and over 26,000 fishes – a total of some 50,000 types of vertebrates. The known number of invertebrate animals, such as clams, worms, octopus, spiders, lobsters, beetles, and butterflies, tops one million. And let's not forget plants, with at least 250,000 known species. Most specialists predict that these numbers merely touch the surface of the proverbial iceberg, and that upwards of 5-30 million or more different species may exist. Of course, all of these species aren't found in all parts of the globe, and some are quite restricted in their distribution. The objective of this chapter is to introduce you to the environmental factors that influence the contemporary distribution of all these species. The study of the geographical distribution of life is called biogeography, and those who study this are bio geographers. It is well known that certain patterns in the distribution of species follow some simple rules. For example, monkeys and their relatives are generally found in tropical areas, and kangaroos are limited to Australia and some nearby islands. Elephants occur in Africa and parts of southern Asia, and polar bears and walrus are found only in Arctic areas of northern North America and Asia. Based on the distribution of species and groups of species, we can perceive the world as consisting of a series of biological regions, or biomes (Fig. 1). Biomes are largely defined in terms of climatic patterns, as we will soon discover. 21

Understanding the factors that produce the major biomes of the world can provide important insights into the factors that have led to the incredible diversity of life that surrounds us, and is the focus of this chapter. Two general classes of factors have led to the observed distribution of life. Historical factors include such events as the advance and retreat of glaciers, the lifting of mountains, formation of islands, and the slow but inexorable shifting of the continents across the surface of the globe. These are interesting in their own right, and constitute a major area of scientific inquiry. However, in this chapter we will focus on the second class of factors, which are ecological factors, and include such things as the timing and distribution of rainfall, annual (and extreme) temperatures, the influence of latitude, and proximity to oceans or other large water bodies, and elevation, to name a few.


The previous essays should have made it clear that everything we do affects wildlife. We are the dominant creatures on this planet and we can choose to wipe out most of the species just by continuing on our present course of accelerating population growth and accelerating resource use. To save wildlife requires positive action; it requires changes in life style and changes in our general way of thinking (or not thinking). We must heed the maxim "Think Globally, Act Locally" and realize we are bound with all other forms of life in one gigantic ecosystem. The following are a few of my suggestions of things you can do to help wildlife (and eventually, help yourselves).


One of the dominant features of our culture is our obsession with "saving time" as though time were something that could be stored in a deep freeze or bank vault. We consume enormous quantities of energy by using "time saving" gadgets from dishwashers to power lawn movers to garbage disposals. We drive powerful automobiles at speeds slightly faster than the law allows to travel to places as quickly as possible. We eat foods in which there is more energy tied up in the packaging than there is in the food itself. All too often the time "saved" is used for trivial amusement: to watch a TV program or play an extra inning of baseball. As individuals, we need to consider the environmental cost of all this collective time saving and act accordingly. Plan long trips for more leisurely driving. Be willing to take the extra time needed to use public transportation or car pools. Make chores into social activities. Take the few extra minutes needed to mow your lawn with a hand mower (and the good, quiet exercise it provides). I am not suggesting a return to living styles of 200 years ago, just some minor adjustments to our present life styles that might reduce such things as air pollution, which is causing atmospheric warming; the demand for dams that destroy streams; and the amount of habitat covered up by garbage.


Neatness is the enemy of wildlife. Much traditional landscaping, for example, is open and neatly trimmed, with little room for birds and other animals, and it often requires heavy use of fertilizers and pesticides. Let the weeds and bushes grow. Plant native trees. Our demand for unblemished fruit and catsup without insect parts forces the heavy use of pesticides and forces farmers to go to great lengths to control birds and other "pests." Blemished or slightly wormy fruit is still edible. My father had the habit of never eating an apple without taking out his pocketknife and cutting it up. This habit was ingrained from being brought up on a farm in the days before the heavy use of pesticides. Adopting simple habits like this can help to save wildlife (and maybe your own health).


"Reduce, Reuse, and Recycle" is a slogan that goes well with "Think Globally, Act Locally." I apologize for presenting these over-used slogans, but they do have a great element of truth to them. All three general activities can make your personal contribution to environmental degradation much less.

Reduce the amount of materials and energy you consume by buying fewer prepackaged goods, driving in an efficient manner (slower, no jack-rabbit starts, etc.), sharing magazines and books, minimizing the use of heating and air conditioning, etc. Reuse items as much as you can. Many "disposable" items are reusable, especially containers. For example, if you make pomegranate wine (as I used to do) you can use old wine bottles year after year (this wine is drunk young). It is also possible to reuse corks, if they are removed from a bottle with an "ah-so" cork remover. Remember to shop using cloth bags or by bringing 'used' bags with you to carry your purchases home. Recycling is just one of many things you can do in your daily life to improve the planet. Many other suggestions are provided in detail in dozens of accessible books on recycling and wholesome living available in most book stores. Lack of information is no longer an excuse for not taking positive action to reduce your impact on the global ecosystem.


The growing public concern for wildlife has led to the establishment of wildlife rehabilitation centers all over the country. These centers take in sick and injured animals and attempt to restore them to health and ultimately release them to the wild. These are staffed largely by volunteers and funded by donations, although wildlife agencies subsidize some of them. Increasingly, such centers are supported by conscience money from companies responsible for oil spills. Such centers are always looking for volunteers to tend the animals and to help with their education efforts, which typically involve taking live animals to schools and talking about them. The animals used in such demonstrations are usually those that are healthy but cannot be returned to the wild (e.g., a hawk with a missing wing). Rehabilitation centers are most valuable in the following situations: 1. Rehabilitating endangered species where each individual can still make a difference to saving the species. 2. Educating the public about wildlife problems with a live animal as the "bait" to draw people in to hear a message. 3. Providing an outlet for people who want to "do something" about the carnage caused by an oil spill or other environmental disaster. A center full of people caring for injured wildlife can also be a visible symbol of a disaster and help arouse sympathy for stronger environmental protection.


Wildlife rehabilitation centers, however, rarely do much for wildlife populations. A majority of the species they treat are common birds, such as red-tailed hawks, barn owls, and mallard ducks, and the evidence that animals rehabilitated and released into the wild survive long enough to reproduce is limited. Recently, Daniel Anderson at UCD, released results of a long-term study of the survival of brown pelicans that had been gooed up during oil spills, cleaned up, and then released; he found that survival and reproduction was low. For more on this theme, see "Essay: Humanity without biology" by Peter Steinhart (Audubon, May 1990, p. 24-27). On the Davis campus, the main rehabilitation center is the Raptor Center (Department of Avian Sciences), in which many of the birds are used for education and some for research.


Modern power boats can be every bit as harmful to wildlife as off-road vehicles. Their wakes accelerate erosion of stream banks and lake shores and disturb nesting of birds such as grebes which build floating nests in beds of rushes and cattails. They pollute the water and air with gasoline and oil. Their noise and speed makes them largely incompatible with wildlife. Large natural lakes with heavy use by powerboats are devoid of waterfowl or have greatly reduced populations. The incredible noise that many boat engines make can disturb wildlife, and the tranquility that many people seek when coming to a lake or stream. Particularly obnoxious are the so-called "personal watercraft", which can go into shallow water (often a refuge for waterfowl), make loud, high-pitched noise, and pollute the water with their inefficient 2-cycle engines. The solution to this problem is to restrict large horsepower or noisy/fast boats to selected reservoirs, lakes, and rivers where people who find noise and fumes essential to their well-being can aggregate. The preferred methods of boating should be to use sailboats, sailboards, canoes, kayaks, and other quite, non-polluting vehicles. Modern sailboats are increasingly safe and comfortable and can provide that all-important family recreational activity. Keep in mind, however, that there can be too much of a good thing; a river crowded with canoes and kayaks may also have its wildlife populations diminished through constant 30 disturbance.

Is it possible to love nature to death? The growing crowds in our national and state parks and in natural areas of all sorts are telling us the answer may be "yes." Even places as remote as the Antarctic are suddenly inundated with tourists and there is some concern that the people may be disrupting the nesting of penguins. In the popular national parks of Kenya, vehicles full of tourists are so common that predatory animals may use them as cover when stalking their prey. These are signs that people who come to natural areas to see animals in their natural setting are changing the behavior of these animals, probably to the detriment of the animals. One of the reasons for this problem is that people often go into a wild area with expectations of seeing the dramatic events shown in wildlife specials on television. At the very least, they want to get close enough to some spectacular animal to get a dramatic photograph or two as a souvenir of the trip. Efforts to see or photograph wildlife close up in the short time available on a vacation trip requires intruding on the wildlife, often at times when the animals are resting, breeding, or taking care of young. As the California Department of Fish and Game points out in one of their brochures for ecotourists "There's a fine line between viewing and victimizing wildlife."


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