1. What is the difference between the different patterns of selection: direction

Question

1. What is the difference between the different patterns of selection: directional, stabilizing, and diversifying?

2. How do bacteria acquire genetic variation and how does that differ from the mechanism by which humans acquire variation?

3. What were the key observations made by Darwin to develop the basic tenants of the theory of evolution? Has this theory been tested?

4. What are the most common misconceptions about evolution and why are they not valid arguments against evolution?

5. The key component of the theory of evolution is natural selection. Define this process. Why is it commonly known as “survival of the fittest”? What are examples of factors (selective pressures) that drive evolution of populations?

6. What is the indirect evidence of evolution? What are homologous and analogous structures? What is convergent evolution? How does similarity of proteins between different species support the idea of evolution?

7. Be able to explain why the following statement is true: Natural Selection works on individuals while evolution works on populations over generations. Or to put it another way: Individuals do not evolve, populations do.

8. How can evolution explain the formation of complex structures such as the eye or the flagella motor?

9. What causes variation in a species? To put this another way: all humans have the same genes, yet we do not look alike. What is the reason fro the phenotypic differences between individuals of the same species? What is genetic recombination?

10. What are the dangers of small populations of a species from a genetic and evolutionary standpoint? What is the bottleneck effect?

11. How does speciation occur? What is the importance of geographic isolation? How is this illustrated in the Galapagos?

12. What is Darwinian Medicine and how does it help us better understand medical conditions?

Explanation / Answer

1. Directional selection is a type of natural selection in which phenotypes at one end of the spectrum are selected against, and phenotypes at the other end of the spectrum are selected for.

Stabilizing selection is a type of natural selection in which a particular trait value is favoured over the other, and the genetic diversity decreases.

Diversifying selection, describes changes in population genetics in which extreme values for a trait are favoured over intermediate values.

2. Bacteria can acquire genes from other organisms by performing conjugation process. This process increases genetic variation in bacteria. This is quite different from the variation acquired by humans. In humans, gene recombination takes place during sexual reproduction, but sexual reproduction would not take place in bacteria.

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