1. Many organisms that can reproduce both sexually and asexually share a reproductive pattern. When the environment is favorable for growth, reproduction is asexual. When the environment deteriorates, sex occurs. Sexually produced offspring remain dormant until better conditions occur. Which of the theoretical ideas about the function of sex is supported by this observation? And which of the disadvantages of sex are less of a problem?
2. From the point of view of development, how does the life cycle of a bacterium resemble the life cycle of an elephant? How does it differ?
3. If a trait is not well adapted to current local conditions, what might be the reasons why it is not, and how might one check to see which of those reason(s) is correct?
4. In many old texts and in some recent popular articles sex is seen as necessary to provide the genetic variability that will keep species from going extinct when the environment changes significantly. What do you think of this explanation?
5. Do ideas, agricultural practices, or computers evolve in response to natural selection? What then corresponds to reproductive success and to inheritance? How does cultural change connect to biological evolution? Neither reproduction nor inheritance can be as precisely defined for cultural change as they can for biological evolution, but the analogy is worth exploring.
Hints for each question:
Here are a few hints for your essay answers. Grades of 90-100 do not involve simple answers or definitions. They must include examples and well thought out arguments. References from the text or our discussions must be included.
1. Find something that normally reproduces asexually but in times of stress reproduces sexually. How does this happen? What does it gain the organisms that do this? Why not always reproduce sexually? What is the benefit of typical asexual reproduction?
2. Think life processes and development. Think about reproduction of each “reproduction at maturity” but also reproduction on a cellular basis ; Similarities and differences of life processes related to development. Think of DNA and genetic material.
3. Think sickle cell anemia and our class discussions. Or provide a different example altogether but your answer must include a well described example.
4. What about bacteria and antibiotic resistance?5. Address the meaning of natural selection and evolution.
Following is a list of 21 questions. You should be able to address/answer each one of them in order to be prepared for the multiple choice section.
1. What is the most important evolutionary difference between sexual and asexual reproduction?
2. How do haplontic and diplontic life cycles differ from each other?
3. Why is bacterial conjugation often described as a form of sex, even though it differs in many respects from eukaryotic sex?
4. Sexual selection only began to operate after the evolution of sperm and eggs because:5. What correctly defines anisogamy?
6. Sex has many disadvantages, including what happening to favorable gene combinations?
7. An asexual genetic system is less vulnerable to the spread of “selfish” genes than a sexual system. True or false?
8. What is considered a life-history trait? What is not considered a life history trait?
9. What kind of variation in a population is represented explicitly in demographic models?
10. A comprehensive understanding of life-history evolution requires what types of information
11. Plants living in an environment with growing seasons that vary unpredictably in length mature:
12. Reproductive investment is determined by the product of the number of offspring and
13. An adaptation is best defined as14. Which of the following conditions are necessary for adaptive evolution in a trait to occur?
I. Variation among individuals in lifetime reproductive success.
II. Inheritance of acquired characters.
III. Heritable variation in the trait.
IV. Little to no genetic variation.
15. The individual features (i.e., phenotypic traits) of all organisms are the result of
16. What are possible evolutionary consequences of neutral genetic variation?
17. What is the relationship between genetic drift and population size?
18. Additive genetic variance is
19. The most likely explanation for the high amounts of molecular genetic variation observed in populations under study is:
20. The maintenance of quantitative genetic variation underlying quantitative traits is most likely maintained by:
21. Reaction norm analysis demonstrates that