Lewis/Life - Answers to End-of-Chapter Questions

Chapter 18 - Answers to End-of-Chapter Questions

TO REVIEW

1. Biological evolution is the process by which the genetic composition of populations of organisms changes over time.

2. Answers may vary but should include something about isolation, adaptive radiation, and competition.

3. Definitions in text.

4. Check text.

5. All organisms are genetically different from all other organisms. The ones with genes that allow for greatest survival (and reproductive capacity) will most likely live to pass along these traits.

6. Only inherited traits are passed along.

7. Traits leading to the greater survival of the species.

8. Change is an ongoing process, still continuing even in the most highly evolved species. Or, looked at another way, what is "perfect" in one circumstance, might well be "imperfect" in another circumstance; geology is constantly challenging organisms with new circumstances.

9. Natural selection.

10. Natural selection.

TO THINK ABOUT

1. Answers may vary but should probably include the possibility that the original birds could fly but over time lost the ability to fly and this loss did not decrease their reproductive or survival capacity. At that time being flightless was neither an advantage nor a disadvantage. When other creatures (namely humans) arrived, being flightless became a selectional disadvantage.

2. Uniformitarianism. Reasons why may vary.

3. Answers may vary. Some students will probably be a bit cynical; mass murder and habitat destruction are hardly more advanced!

4. No, because you didn't alter the dog's genes.

5. Answers will vary but should include the radiation of more virulent strains.

6. Genetic immunity.

7. Answers will vary.

8. This answer would depend on what else the snakes could or could not eat. Worst case scenario: The venomous snakes would die out because they would not be able to immobilize (and thus dine on) their prey.

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