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Appendix | Answer Key

CHAPTER 1Check Your Progress1.1 Observation data; observing that a worker ant produces eggs. 1.2 Test group: colonies exposed to the parasite; control group: colonies not exposed to the parasite. 1.3 a. Levels of organization from cells to organism illustrate order; (b) unicellular organisms divide, multicellular ones produce sperm and egg (c) metabolizes nutrients. 1.4 When organisms reproduce they pass on a copy of their genes. 1.5 Only by responding to stimuli can organisms remain homeostatic. 1.6 Natural ecosystems absorb pollutants. 1.7 The fi rst suggests that humans are apes; the second means that apes and humans are on their own evolutionary pathway. 1.8 a. Domain Eukarya and kingdom Animals b. Fossil and molecular data 1.9 Better adapted members have the opportunity through natural selection to reproduce more, and in that way a species becomes adapted to its environment. 1.10 The hawk has levels of organization; catches food for herself and offspring; remains homeostatic because she can respond to stimuli, lives in a semidesert ecosystem; and is adapted to fl ying.

Form Your OpinionPage 6: 1. No answer: The United States should not continue to export its current farming technology. Exporting technology that is known to be detrimental to ground water and top soil will eventually reduce agricultural yields, resulting in a food shortage. The United States would be better served to encourage sustainable farming practices like crop rotation to foster long-term success in agriculture. Yes answer: The United States should continue to export farming technology to other countries in order to support the global food market. As solutions to the long-term problems of these technologies arise, the U.S. should make these available to other countries as well. 2. Circumstances such as labor costs, profi ts, and marketing challenges might discourage a farmer from growing organically. These obstacles might be overcome through government subsidies for sustainable farming practices, sharing best practices through networking with successful organic farmers, and a world-wide movement towards eating primarily locally grown and seasonal produce. Page 17: 1. Practical problems in agriculture, medicine, and conservation can be solved with a knowledge of evolution. Because we know that natural selection drives the evolution of pesticide resistant insects, changes to farming practices and pesticide use are possible. In medicine, awareness of the evolution of antibiotic resistant bacteria allows patients and doctors alike to make changes to the way antibiotics are prescribed and used. In conservation efforts, knowledge of evolution can be used to make informed decisions regarding endangered species; directed evolution can also be used to select for organisms to clean up the environment. 2. By naturally allowing for the growth of nonresistant insect populations, farmers

can reduce the infl uence of pesticide resistant insects on their fi elds and farming practices. 3. The salmon must be successfully raised in an environment that mimics nature as closely as possible, with exposure to pressures such as normal predation and pathogens, for example, if they are to succeed in the wild. For instance, if the salmon have no exposure to pathogens that they might encounter in the wild, these salmon are at high risk of infection upon introduction without the benefi t of building immune defenses from previous exposure.

Testing Yourself1. a; 2. d; 3. c; 4. Scientifi c theories arise due to innumerable observations and experimentation. 5.b; 6. c; 7. b; 8. c; 9. c; 10. d; 11. Each type organism has its own sequence of bases in its genes. 12. e; 13. b; 14. d; 15. a; 16. d; 17. d; 18. A college campus has a location, as does an ecosystem. The populations of students, faculty, and administrators communicate with each other and the physical environment (the buildings). 19. c; 20. e; 21. d; 22. d; 23. c; 24. a; 25. c; 26. c; 27. Evolution is related to all the other theories; for example, all organisms are cellular because their common ancestor was cellular. 28. e; 29. f; 30. c; 31. g

Thinking Scientifi cally1. a. Bacteria don’t die in sunlight when dye is present. b. Dye is protective against UV radiation. c. Experiment consists of exposing control and test groups to UV light. d. Hypothesis is not supported. 2. Plant the same species of tomato plants in three large plots. All plots receive the same treatment, except plot 1, your control, receives no fertilizer; plot 2 receives the name brand fertilizer in the same quantity as plot 3 which receives the generic brand. Measure the tomatoes from each plot and calculate the average size to determine which plot results in the largest tomatoes.

Put the Pieces TogetherPage 21: 1. One example, that shows the relationship between two theories, is the link between ecosystems and evolution. Different species of organisms are the result of evolution over time from a common ancestor. The evolution of new species creates new populations that interact to form communities, which in turn interact to form ecosystems. Ecosystems also evolve over time as new species evolve and change the populations and communities within the ecosystem. 2. The evolution of antibiotic resistant bacteria results from natural selection. Mutations in bacterial DNA created resistant individuals. These bacteria survive to reproduce in the presence of antibiotics, whereas non-resistant individuals die off. This process creates a population of antibiotic resistant bacteria.

CHAPTER 2Check Your Progress2.1 Carbon, nitrogen, phosphorus, sulfur. 2.2 See Figure 2.3B, page 29, in text. 2.3 a. One. Hydrogen

has one shell, which is complete with two electrons; b. Two. Oxygen has two shells with six valence electrons in the outer shell. Therefore, oxygen requires two more electrons for a completed outer shell. 2.4 H+, OH-. 2.5 a. See Figure 2.6, page 32, in text; b. This is the formula that gives each atom a completed outer shell. 2.6 One end of the molecule is negative and the other end is positive because oxygen attacts electron more than hydrogen does. 2.7 Yes, because electropositive hydrogens are attracted to either electronegative oxygen or nitrogen. 2.8 Hydrogen bonding causes water molecules to stick together and to other polar molecules. 2.9 The air loses heat as it causes water in the pad to evaporate. 2.10 Polarity makes the emulsifi ers hydrophilic. 2.11 The blocks of ice trap heat inside and prevent it from escaping to the environment. 2.12 a. H+; b. OH-. 2.13 a. Acidic; b. More H+. 2.14 a. Down; b. Carbonic acid froms and releases H; therefore the pH decreases.

Form Your OpinionPage 28: 1. Though controversy will undoubtedly arise over moral, monetary and other issues, science must be free to ask and answer questions about the world in which we live. However, scientists should conduct research with minimal risks to their own safety and that of others. As technology advances, the restrictions placed upon research should be reevaluated to ensure their relevance. With careful and balanced monitoring, scientifi c endeavors should be supported and encouraged. 2. Safety should be paramount in experimentation. The best way to proceed is to aware of advisements regarding safety and to learn from experience about how to modify procedures to make them safe. 3. Yes answer: Depending on the benefi ts that an experiment might have, I would consider being a guinea pig. However, research using people should be entirely voluntary and provide an explanation of the potential risks. I would be particularly willing to be an experimental subject in the fi eld of medical research, especially if the results of experimentation had the potential to prove widely useful. No answer: I would not be willing to serve as a guinea pig in experiments that may prove harmful to me. Because of known risks, and the fact that the risks associated with experimentation on humans and animals cannot always be predicted, I would be unwilling to subject myself to the potentially hazardous side effects of being a human subject in experiments. Page 38: 1. The changes in lakes due to acid rain kill fi sh and other wildlife and sometimes eliminate it altogether. Trees suffer as a result of acid rain’s effects, becoming diseased or dying. If this continues, not only will the atmosphere’s oxygen be affected, but the lumber industry will suffer. The food supply is at risk if plants as well as fi sh are negatively affected by acid rain. 2. Human beings must take some responsibility for what they do to the planet and make attempts to control their negative impact. Driving less could help to preserve lakes and the wildlife in them, forests, buildings made of limestone and marble, and

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