L100 -- Study Guide Exam Three

Evolution:

1. Define evolution - come up with as many definitions as you can that can explain evolution in a biological sense.

2. What are the different forms of evidence for the theory of evolution? Be sure you can explain them and why they provide evidence. This is not a short answer.

3. Define microevolution.

4. Assuming a non-evolving population, where the allele frequencies are at an equilibrium, we can express the frequency of alleles in a given population as p + q = 1.  (assuming only two alleles)   If given the frequency of one allele, you should be able to calculate the frequency of the other allele.  

5.  Again, assuming a non-evolving population,  if given the frequency of a particular genotype or phenotype in the population, e.g., homozygous recessive, you should be able to calculate the frequency of individuals in the population who are carriers for the recessive allele (heterozygous), homozygous dominant, express the dominant phenotype or recessive phenotype, etc.

6.  Under what conditions is genetic equilibrium disturbed (in other words, what are the agents of microevolution)?

7. What is evolution by natural selection? Briefly consider this question in terms of changes in allele frequencies over time. Think about the natural select experiment you did in the lab. More in depth questions on natural selection are asked later.

8. Evolution is frequently defined as the change in allele frequency in a population over time.  Understand how genetic drift, gene flow, mutations and natural selection can all impact allele frequencies.  

9. What is a bottleneck effect?  Why is genetic drift likely to occur after a bottlenecking event? 

10. What is a founder effect?  Give an example (hypothetical is fine), and explain how and why the individuals in the new population will likely diverge genetically from the parent population over time. 

11. What were the observations Darwin made on his voyage on the Beagle that helped to formulate this theory of evolution by means of natural selection?

12. Why (or how) did the geologist Charles Lyell's description of a very old earth that was modified very slowly over time by geological processes influence Darwin's thinking?

13. Explain evolution by natural selection. What are the main conditions that must be true in order to natural selection to occur?

• What is meant by differential reproduction?
• What role does variation play in natural selection?
• Try to explain the evoltuion of a pesticide-resistent population of insects in evolutionary terms.

14. What is meant by an evolutionary adaptation? Give an example and explain why it is adaptive (you don't have to use a specific example from class, instead I want you to be able to explain why a character would be considered adaptive).

15.  Understand the process of natural selection (review the example of Darwin's finches and the work by Rosemary and Peter Grant). 

16. Explain the evolution of pesticide resistance or antibiotic resistance.

17. Why is variation in the phenotypic expression in the population critical for natural selection?  What are the sources of variations in phenotypes (think back to meiosis lecture) and which are most likely to play a major role in the evolution of new traits and ultimately a new species?

18. Explain what I mean when I say that natural selection operates at the level of the individual while evolution occurs at the level of the population. Explain how allele frequencies can change in the population in the face of selection on a phenotype (my Leaf Mantid example in lecture; also refer to your lab #11).

19. Understand the differences / similarities between stabilizing selection, disruptive selection and directional selection.