Biology Life on Earth with Physiology, 12th Edition Gerald Audesirk Solution Manual

Type:

Solution Manual

Resource:

Biology: Life on Earth with Physiology

Edition:

12th

Author(s):

Gerald Audesirk Teresa Audesirk Bruce Byers

Chapter 1 APPLYING THE CONCEPTS HINTS 1. How does the definition of a scientific theory differ from the everyday use of the term “theory” as just an idea? Why do scientists retain the term “theory” even for concepts that would generally be considered scientific facts?

2. Which of the properties of life described in this text do viruses lack? Which do they possess? How would you alter the criteria to allow viruses to meet the new criteria? Ask yourself the same questions for prions.

3. What manipulations did the experimental bacteria receive that should be duplicated in a control?

4. You’re on your own here.

5. You’re on your own here.

CONSIDER THIS HINT Case Study Revisited If viruses or other pathogens are synthesized responsibly, might this help develop countermeasures against the use of these agents by bioterrorists?

Chapter 2 APPLYING THE CONCEPTS HINTS 1. Think about what properties the molecule would need to form hydrogen bonds with water and what properties it would need to interact with hydrophobic fats. Now imagine these different properties in the same molecule.

2. Think about the evaporation of water and specific heat. Now consider how high humidity influences the ability of water to evaporate and how high humidity affects evaporative cooling by sweating.

3. Water has about five times the specific heat of granite. What does this say about the energy removed from your drink as it warms ice compared to warming an equal weight of granite of the same temperature? If you research the “heat of fusion” of water, you will learn that it takes still more energy to transform water from ice to liquid water. This energy would also be absorbed from your drink, further cooling it as ice cubes melt.

CONSIDER THIS HINT Case Study Revisited How important are the safety and waste storage risks of nuclear power? How important are the pollution, sustainability, and climate change risks of burning fossil fuels? Can any of these risks be lessened? How? What are the main advantages of each technology?

Wind and solar energy are viable alternatives to nuclear power and fossil fuels. What is the best strategy for increasing use of these alternatives?

Chapter 3 APPLYING THE CONCEPTS HINTS 1. Which end would face the water? Which end would face other phospholipids?

2. Hydrophilic molecules tend to attract and hold water to them, and water is heavy.

Hydrophobic molecules do not attract water.

3. Would veggies still be diet food? Would we require as much cropland to feed the same number of people? Would we have domesticated the same types of plants? Would we have different types of teeth? Would people buy as much of their food?

CONSIDER THIS HINT Case Study Revisited There is no single correct answer, but you should consider the mode of transmission of BSE to people.

Chapter 4 answers APPLYING THE CONCEPTS HINTS 1. Which individual would require more energy?

2. Does the cytoskeleton perform any functions other than support?

3. Would the interior be close to the cell membrane? Could a very large cell assume a different shape to meet its needs?

CONSIDER THIS HINT Case Study Revisited Questions to consider: Are adequate donor transplants available? Will your immune system accept them readily? What risks are involved in an experimental therapy?

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Chapter 5 Answers Applying the Concepts Hints 1. Does fresh water tend to flow into or out of Paramecium? How would aquaporins affect the movement of water through its plasma membrane?

2. Oil is hydrophobic; which part of the phospholipid is hydrophobic?

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Chapter 6 answers CONSIDER THIS HINT Earth Watch Consider the potential effectiveness of such laws, your general view of the role of government regulation, and which level of government (local, state, national, all, none) should address waste management issues.

APPLYING THE CONCEPTS HINTS 1. Assume your power is generated by a conventional power plant burning fossil fuel (coal, oil, or natural gas) or by wind or solar energy. Where does the energy from all these sources ultimately come from?

2. Remember that Earth is not an isolated system.

3. Remember what happens to energy when it’s converted from one form to another. Is all the energy of a prey organism available to the predator that eats it?

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Chapter 7 APPLYING THE CONCEPTS HINTS 1. Look at Figure 7-9, showing the Calvin cycle. Notice which molecule provides the carbon that is made into G3P and ultimately into sugar. Now look at Figures 7-7 and 78, showing the light-dependent reactions. Notice which molecule provides the oxygen that is liberated by oxygen gas.

2. Are H+ being moved into or out of the space? What pH is characterized by excess H+?

3. Which wavelengths of light are least utilized by chlorophylls and carotenoids? If a pigment absorbed only these underutilized wavelengths, which color wavelengths would it reflect? If photosynthesis could be made more efficient, what advantages would this have for agriculture?

CONSIDER THIS HINT Case Study Revisited What scenarios or individual choices might slow human population growth? What can be done in the meantime to minimize species extinctions?

Chapter 8 APPLYING THE CONCEPTS HINTS 1. For maximum energy production, which process will the bacteria use? What will this do to oxygen availability? How will this change in oxygen affect energy production?

2. Raw sewage contains high levels of nutrients. What changes in oxygen levels will raw sewage cause? How will this affect fish? How could oxygen be restored to a small pond?

3. Can a cell break down glucose without ATP? 4.What form of energy production would the bacteria use at the beginning of the summer? What change in conditions would this cause? Would this change favor glycolysis or cellular respiration? Which produces the most energy?

Chapter 9

APPLYING THE CONCEPTS HINTS 1. Because most nerve and heart muscle cells do not divide, if these cells die, they are usually not replaced. Therefore, the damaged organs are never repaired, and deficits in brain or heart function are lifelong.

2. Generally, treatments that cure cancers, or at least greatly reduce their rate of growth, act by reducing the rate of mitotic cell division. Cell division is essential for many bodily functions, including hair growth, skin repair and replacement and maintaining and repairing the linings of the lungs, stomach, and intestine. Any treatment that reduces cell division indiscriminately will interfere with these functions and will therefore have “side effects,” including hair loss, skin defects, and digestive upset. Any treatment that truly cures cancer without side effects must distinguish between cancerous cells and normal cells. Improved cancer therapies should therefore target the aspects of cancerous cells that differ from normal cells, such as possible differences in cell surface proteins, different responses to hormones or growth factors, or the ability to promote the growth of blood vessels to nourish developing tumors.

Chapter 10 APPLYING THE CONCEPTS HINT 1. How similar are the environments likely to be for parents and offspring if the offspring are produced by runners or by seeds (which are eaten by animals and excreted in their feces)?

Chapter 11 Applying the Concepts Hints 1. A gene is a specific segment of DNA at a particular location on a chromosome (its locus) that normally encodes the information needed to synthesize a specific protein. An allele is an alternative form of a gene, composed of a specific nucleotide sequence at a given gene locus.

Would it be correct to say that two people have different genes, or different alleles? Why? 2. Assuming that the relationship between genotype and phenotype works similarly in the alternate universe and in our universe, what factors determine phenotype?

Consider This Hint Case Study Revisited: Sudden Death on the Court List the pros and cons of altering the genetic makeup of the gametes and embryos. Consider the range of genetic traits that parents might wish to alter. Think about who would determine which kinds of changes are permitted.

Chapter 12 Applying the Concepts Hints 1. In the alternate universe, how many nucleotides would be needed to specify 20 different amino acids, plus start and stop? Therefore, would the same number, fewer, or more nucleotides be needed to spell out the sequence of amino acids in a protein, compared to organisms on Earth?

2. Using English as a model for the language of DNA, take a short sentence such as “To be or not to be” and construct its complementary sentence using a “letter-pairing” rule such as “z” is complementary to “a,” “y” is complementary to “b,” and so on. Would the complementary sentence make sense? If you had a paragraph consisting only of complementary sentences, could you use the complementary sentences to re-create the meaningful sentences?

Chapter 13 Applying the Concepts Hints 1. Think about whether introns, promoter sequences, and stop codons remain in the transcript.

2. Would the affected person produce one or two different types of CFTR proteins? How would the outcome be affected by the degree of functionality of the protein produced by each mutant allele?

Consider This Hint Case Study Revisited: Cystic Fibrosis Although there is no correct answer, find out relevant facts that might help to inform your opinion. For example, search the Internet for the sources that contributed funding for the research that led to the discovery and clinical trials for ivacaftor; how insurance companies typically pay for drugs, and whether there is a lifetime maximum benefit; and how much the cost of discovery and trials compares to the profit being made from the drug.

Chapter 14

Consider This Hints Doing Science: Using Genetic Markers to Breed Tastier Fruits and Veggies Both genetically modified plants and plants produced by marker-assisted breeding have an altered genome as a result of advanced technology. Considering this, is it justifiable to reject one technique but accept the other?

Case Study Revisited There is no single answer to this question. Can laypeople or politicians—or scientists, for that matter—accurately predict which type of research will yield the most benefits? On the other hand, how many resources can society afford to devote to science?

Applying the Concepts Hints 1. Long before transgenic crops were developed, Bacillus thuringiensis was used to control insects by spraying the bacteria on a field. Is there likely to be any significant biological difference between Bt resistance that evolved as a result of spraying B. thuringiensis on a field and Bt resistance that evolved as a result of planting transgenic Bt crops?

2. Work out the possible offspring that could be produced from all feasible sets of parents.

Constructing a Punnett square may be helpful.

Chapter 15 APPLYING THE CONCEPTS HINTS 1. Consider the likely effect of natural selection on a complex, energy-consuming anatomical structure that provides no benefit to its possessor.

2. Consider how the “best” traits might change when environmental conditions change.

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Chapter 16 APPLYING THE CONCEPTS HINTS 1. Think about the difference between evolutionary change and nonevolutionary change caused by individual responses to environmental change. Think about the information you would need to distinguish between the two.

2.

Consider the possible consequences of reduced genetic diversity.

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Chapter 17 APPLYING THE CONCEPTS HINT 1. Remember that your experiment must test for successful interbreeding under natural conditions. When choosing a study species, consider generation time and ease of evaluation of interbreeding.

CONSIDER THIS HINT Earth Watch Consider the institutions that currently make policy decisions and the ones that decide how to implement those policies. Think about whether these institutions and their procedures are capable of saving species. Think about whether decisions about saving species should be based mainly on human needs, or if other factors should be considered.

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Chapter 18 APPLYING THE CONCEPTS HINTS 1. List some economic and ecological benefits that humans gain from biodiversity. Think about where new drugs and foods come from and the ways in which we depend on functioning ecosystems. Consider our ethical obligations to other species.

2. Arguable possibilities include the origin of photosynthesis, the origin of aerobic respiration, the origin of multicellular bodies, or the invasion of land.

CONSIDER THIS HINT Case Study Revisited Think about traits that are distinctively human; some of these may have not been present in Neanderthals or Denisovans. Think about which of these potential differences could conceivably be related to differences in genes or gene expression.

Chapter 19 APPLYING THE CONCEPTS HINTS 1. Consider how ecotourism, bioprospecting for new drugs, and exporting renewable forest and ocean products might affect local communities in poor, tropical regions.

2. Consider how convergent evolution might confound attempts to infer past evolution from present traits. Think of the kinds of clues available to modern biologists that were not available to earlier generations.

3. Examine the relevant phylogenetic tree figures to determine which of the named groups contains all the descendants of its common ancestor.

CONSIDER THIS HINT Case Study Revisited If we understand how changes in the environment of a disease-causing organism have influenced its evolution, consider how we might modify the organism’s environment in ways that benefit human health. Recall that the environment of many disease-causing organisms is the human body.

Chapter 20 CONSIDER THIS HINT Case Study Revisited Think about the kinds of societal needs that are best addressed by market forces and the kinds that are best addressed by government action. In which category does food safety testing fall, and why?

APPLYING THE CONCEPTS HINTS 1. Consider the main public health problems in the developing world, as well as access to health care professionals there. Think about how the evolution of disease-causing bacteria is affected by widespread exposure to antibiotics.

2. Why are even well-supported scientific conclusions considered tentative?

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Chapter 21 APPLYING THE CONCEPTS HINTS 1. Does each cell in a multicellular organism need to perform all of the cellular processes necessary to keep the organism alive and functioning?

2. List the essential services that single-celled organisms provide. (One example is nitrogen fixation; there are many more.)

CONSIDER THIS HINT Case Study Revisited List some of the harmful effects of invasive species. Then try to develop and support the argument that species invasions are natural and inevitable.

Chapter 22 APPLYING THE CONCEPTS HINTS 1. Think of steps that could help return to a country some of the wealth generated by medicines discovered in its protected forests.

2. Consider the likely function of the tannin in acorns. Also consider the role of chance in determining which species are domesticated.

Chapter 23 APPLYING THE CONCEPTS HINTS 1. Consider the effects of a lost tree species. Think about characteristics of fungi that facilitate transport to distant locations (especially if aided by humans).

2. Consider what your home would be like if garbage were never removed from it.

CONSIDER THIS HINT Case Study Revisited Begin by developing a working definition of “organism.”

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Chapter 24 APPLYING THE CONCEPTS HINTS 1. One important service performed by diverse insect species is pollination. Think of others. Consider whether we have an ethical responsibility to non-human animals.

2. Possible criteria for gauging a species’ success include abundance, biomass, geographic spread, and duration of existence.

CONSIDER THIS HINT Case Study Revisited List the potential benefits of treating ailments with live animals; then list the potential risks.

Chapter 25 APPLYING THE CONCEPTS HINTS 1. Think about the elements that are present and absent in a hagfish skeleton. Consider that classification schemes ought to reflect biologists’ understanding of evolutionary history.

2. Consider the proverbial canary in a coal mine.

CONSIDER THIS HINT Case Study Revisited How valuable is scientific knowledge about evolution and the history of life on Earth?

Chapter 26 Applying the Concepts Hints 1. Think about whether it is more important to attract male mosquitoes or female mosquitoes to your trap. Or do you need two kinds of traps? For trapping moths, consider the kinds of signals that they use for mate attraction.

2. In non-human animals, both dominance hierarchies and territoriality reduce overt conflict, to the ultimate benefit of all members of the social group.

3. Consider stimuli that birds might avoid, but also think about how you can overcome the effects of habituation.

Consider This Hint Case Study Revisited: Sex and Symmetry Consider how comparisons of the criteria for beauty in different cultures might be used to distinguish innate from learned preferences. Think about how to ensure that different cultures represent independent data points (that is, have not influenced one another).

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Chapter 27 Applying the Concepts Hints 1. What is the predominant religion? Does it allow contraception? Does it promote large families? Do other social factors promote large families? What is the average level of education in the country? Do women have equal access to employment and education? What percentage of reproductive-age women uses modern contraception? Any contraception?

What is the child death rate? The Population Reference Bureau is a good starting place.

2. Factors to consider: Why did the species become endangered (were their numbers always low, or did human activities contribute to their decline)? How specialized are the species (for example, what is their geographic range; do they eat a variety of foods, or only one or a few types)? How much habitat do they need to survive and breed? How might these factors contribute to population decline and recovery?

Consider This Hint Earth Watch: Have We Exceeded Earth’s Carrying Capacity?

Questions to think about include: What would be the consequences to people and the environment in the exporting country? What about in the importing country? If a domestic product could substitute for the imported product, would the domestic product have a smaller ecological impact than the imported product?

Chapter 28 Applying the Concepts Hints 1. Think about what a larger beak would be good for. What observations could you make to determine whether the larger beak is helping one species reduce its competition with the other?

2. What is the typical time course of succession, compared to a human life span? How could you tell if an area has a climax community or not? Could you study succession in a single small location, or would you need to look at several places in the same general area?

Consider This Hint Earth Watch: Invasive Species Disrupt Community Interactions Consider the benefits that introduced species provide to people and/or the natural environment, and compare these benefits to the possible harm if a non-native species becomes invasive. Can the likelihood of a species becoming invasive be accurately predicted before it is imported?

Chapter 29 Applying the Concepts Hints 1. Which trophic levels have the greatest amount of energy, and therefore the greatest amount of calories? How does this relate to a vegetarian diet versus a diet that includes meat?

2. What effects will a growing human population have on efforts to reduce the burning of fossil fuels?

Consider This Hints Earth Watch: Climate Intervention⎯A Solution to Climate Change?

In comparing climate intervention and emissions reduction, think about whether they differ in how long they would take to implement, in how permanent their effects would be, and in how difficult they would be to implement in a world with so many different national governments.

Case Study Revisited: Dying Fish Feed an Ecosystem Consider the benefits that spawning salmon bring to coastal ecosystems in Alaska, the Pacific Northwest, and other areas where Pacific or Atlantic salmon spawn. Are these benefits related to the number of salmon species, the abundance of individual species, or both? Are the benefits gained from wild salmon the same as those gained from farm-raised salmon?

Chapter 30 Applying the Concepts Hints 1. What two factors determine the nature and distribution of terrestrial biomes? How do these factors differ between Fairbanks, eastern Montana, and Tucson?

2. Is the surface of Earth uniform? What processes move water and heat around the planet?

What features act as obstacles to the movement of water and heat?

Consider This Hint Case Study Revisited: Can Coffee Save Songbirds?

Think about whether the total amount of land under cultivation for coffee is expanding or not.

Consider whether species diversity and abundance differ between rustic coffee plantations and intact rain forest. What kind of research might help you determine if your guesses about these topics are accurate?

Chapter 31 Applying the Concepts Hints 1. Think about energy consumption in your car, your school, and your home. Where does your food come from? How does it get to your dinner table?

2. The Web sites for the U.S. Fish and Wildlife Service, your state division of wildlife, and environmental organizations such as the World Wildlife Fund, National Wildlife Federation, and the Nature Conservancy are good resources.

Chapter 32 Applying the Concepts Hints 1. What physical parameters are more variable on land than in water (especially in oceans)?

2. Examine Figure 32-9. Where are cells that can reproduce by cell division located? Where are sensory nerve cells located?

3. Feel free to design a Rube Goldberg (look him up!) machine here. Don’t make it too complex, however, or the parents may get confused.

Consider This Hints Earth Watch: Positive Feedback in the Arctic While positive feedback in the Arctic will accelerate global warming, the undesirable consequences of global warming will lead to various types of negative feedback. Think about and list the various factors that are causing humans to pump increasing amounts of CO2 into the atmosphere. After each factor, describe how negative feedback might reduce it.

Case Study Revisited: Overheated Some economists try to place a value on a human life, for example, by estimating the lost work and income. Is lost economic productivity the only—or the best—measure of the value of a human life? Does this mean that the lives of older, retired people are without value?

Chapter 33 Applying the Concepts Hints 1. Consider what would happen in the alveoli if the heart pumped blood into the lung with the force required to circulate blood throughout the body.

2. In a competition, you try to pick the best qualified person. If there is competition for a heart transplant or bypass surgery, what factors would you look for that would make one person more able to benefit from the process than another person?

Consider This Hint Case Study Revisited: Living from Heart to Heart Consider which personal views and beliefs might influence your thoughts on becoming a donor.

Have your views been influenced by an experience with a family member or friend who needed a transplant?

Chapter 34 Applying the Concepts Hints 1. Under what conditions would you select a smoker?

2. Might “e-cigs” entice non-smokers to begin smoking them and become addicted to nicotine?

Would replacing tobacco cigarettes with e-cigs avoid some tobacco-related health effects?

Might a low-nicotine cigarette give smokers the impression that the cigarette is rather harmless? Might either type of modified cigarette help smokers to quit?

3. Mary would become unconscious before she died. Could she still hold her breath in an unconscious state?

Consider This Hint Case Study Revisited: Straining to Breathe--with High Stakes Could all of these methods, including synthetic EPO and transfusions, be considered unnatural shortcuts to higher performance? Do the legal methods differ fundamentally because they don’t involve any medical procedures or artificial substances? Do they put aspiring athletes who cannot afford these approaches or object to them at a disadvantage?

Chapter 35 Applying the Concepts Hints 1. The artificial sweetener contributes almost nothing to the size of each cookie, so what remaining ingredients replace it to make the cookies the same size as those with sugar? How do these combined ingredients compare to sugar in caloric value?

2. Leptin is produced by fat; low levels stimulate hunger. Why shouldn’t high levels reduce hunger? Over their evolutionary history, were humans more likely to experience obesity or starvation?

3. How has the food industry designed foods to appeal to our instinctive urges to seek and enjoy weight-promoting foods? What stimuli trigger the desire to eat, and when and where do you encounter them?

Consider This Hint Case Study Revisited: Dying to Be Thin Could these restrictions be achieved by legislation, or would they need to be voluntary? If voluntary, what incentives would be needed to cause change?

Chapter 36 Applying the Concepts Hints 1. How concentrated can human urine become relative to human blood? Would this be sufficient to prevent a net gain of salt from seawater?

2. Under normal circumstances does the urinary system excrete substances that are required by the body? What major component of urine might you want to restore to the body under extreme conditions?

Consider This Hint Case Study Revisited: Paying It Forward This is a personal decision that should be made after considering the health risks to you versus the benefits to a loved one or to society.

Chapter 37 Applying the Concepts Hints 1. Think about what happens to the large, complex molecules, such as proteins, in the food you eat and where the products of digestion go in your body.

2. Refer back to the discussion of how the body defends against cancers. What would happen if these defenses were inhibited?

Consider This Hint Case Study Revisited: Flesh-Eating Bacteria There is no single correct answer. Factors to consider include the (perhaps selfish) desire of individuals to remain healthy or to be cured of disease; the severity of the current disease suffered by a patient; uncertainties in how severe a current disease already is or will become; the likelihood that bacteria will become resistant owing to possible excessive antibiotic use; and the likelihood that new antibiotics or other treatments will be developed to replace antibiotics to which bacteria have become resistant.

Chapter 38 Applying the Concepts Hints 1. See the section on thyroid action in the text. What would you predict would be the effects of water, extra thyroxine, and no thyroxine on tadpole metamorphosis?

2. Review the section in this chapter about the pineal gland. What happens to day length in the spring?

Chapter 39 Applying the Concepts Hints 1. Do larger or smaller axons conduct action potentials more rapidly? What is the effect of myelination?

2. Are reflexes fast or slow? How flexible are they if conditions change?

Consider This Hints Doing Science: Neuroimaging: Observing the Brain in Action Revisit the accuracy of DNA testing and eyewitness testimony (see Chapter 14). In addition, research the lying abilities of psychopaths.

Case Study Revisited: How Do I Love Thee?

Who is exposed to the highest concentration of oxytocin—the wearer or the prospective targets?

Assuming that oxytocin colognes work, would this be an ethical thing to do to your friends, potential sexual partners, or business associates? Would it differ ethically from other characteristics or techniques, such as wearing makeup, dressing attractively, or being nice to someone you actually don’t like?

Chapter 40 Applying the Concepts Hints 1. Certain types of odors correspond closely with the edibility of an object, with sexual receptivity, or with other characteristics of the environment. For example, sulfurous smells are often produced by rotting food that would be poisonous to eat. How might emotional responses help animals to identify foods, keep from being poisoned, or find a mate? Would animals with very different diets—not to mention very different choices in potential mates— respond to odors the same ways that we do?

2. What happens to plants that are tasty to animals? Are foods more likely to spoil in hot climates or cold climates?

Chapter 41 Applying the Concepts Hints 1. Would the heart be able to contract spontaneously? Would a wave of contraction spread through the heart? Might the fibers separate during contraction?

2. What symptoms would a person experience if they could not adequately contract their skeletal muscles? If you block an enzyme that would normally help remove a transmitter from the synapse, what will this do to the ability of the neuron to stimulate the muscle?

Could this help compensate for a lack of receptors?

Consider This Hint Case Study Revisited: Legs of Gold Will the child’s abilities and preferences become obvious without the need for being steered into a particular sport? How might ambitious parents misuse this information in ways that might harm the child physically or emotionally?

Chapter 42 Applying the Concepts Hint 1. Consider the hormones produced by a maturing follicle and the likely effects of the absence of these hormones.

Consider This Hints Health Watch: High-Tech Reproduction How much DNA is in a mitochondrion compared to the nucleus? What types of traits do mitochondrial genes encode? Might these change physical, intellectual, or psychological traits of the offspring? Is changing the genetic makeup of a person ethically the same, or different, depending on whether the DNA is in mitochondria or the nucleus?

Case Study Revisited: To Breed a Rhino Rhinos produce only a single offspring at a time, usually separated by several years. Assume that they can be stimulated to produce multiple eggs. How do women who are unable to bear their own children sometimes reproduce? Might this work with rhinos? Why or why not?

Chapter 43 Applying the Concepts Hints 1. What typically happens with transplants that do not involve the organizer?

2. Consider the evolutionary descent of mammals.

Chapter 44 Applying the Concepts Hints 1. Think about what mineral nutrients often limit a plant’s growth and what nutrient is a major component of fertilizers applied on farms.

2. What are the driving forces for water movement into the vascular cylinder of a root? How would a high salt concentration in soil water affect water movement?

3. Grasses undergo only primary growth. Does mowing cut off differentiated cells or meristem cells of grasses? How do dicots differ in the location of their apical meristems? What types of cells would be cut off if you mowed a “lawn” of oak seedlings?

Consider This Hint Case Study Revisited: Autumn in Vermont How would tourism be affected if the duration or intensity of fall colors changes? How would the maple syrup industry be affected if maple trees are driven north by climate change? Are there ways that shorter, warmer winters might benefit the economy?

Chapter 45 Applying the Concepts Hints 1. Review the mechanisms that maintain seed dormancy. Think of what you might do to overcome these mechanisms.

2. Is it advantageous for a plant to appeal to a specific species of pollinator? Is it advantageous for a pollinator with a special kind of “tongue” to specialize on a specific type of flower that stores its nectar where other pollinators can’t reach it? What would happen to the plant if its pollinator became rare or even went extinct?

3. What types of materials do people transport that might have plant seeds as “hitchhikers”?

Why might people deliberately import plants from other countries? Consider doing an Internet search for “invasive weeds” to supplement your answer.

Chapter 46 Applying the Concepts Hints 1. In nature, are seeds usually oriented “correctly”? What adaptations do seeds have to overcome “incorrect” orientation?

2. How much does day length vary at the equator?

Consider This Hint Earth Watch: Where There’s Smoke, There’s Germination Human encroachment in and near publicly held natural areas creates some no-win situations.

What weather conditions should foresters consider? How should they educate local residents, both in general about burning and immediately prior to the burn? What precautions should foresters take during the burn? Should they consider mechanically clearing excess brush and overly dense trees? What stimulus for plants would be missing if they did this?

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