3c: How could the total road kills go down, as the nests are going up? (Nests are something scientists use to estimate the size of adult swallows surviving long enough to reproduce.) 3d: What about the environment contributes to a change in the average wing length in the cliff swallow population over generations? 3e: What is the role of natural selection in explaining the change in average wing length in the population over generations?

Try to outline a scenario explaining the evolution of the three species shown in panel g. Use migration, mutation, genetic drift, selection, reproductive isolation, gene flow, extinction, and many generations in your scenario. Based on your scenario, what are the components that are necessary in a population in order for it to split or diverge into two new daughter species from a single ancestor (the parent species)?

As we saw last week, population size is important. Ideally, this means you started with a lot of genetically diverse founders, but of course that isn’t always the case. In the case of the Española Galapagos tortoises it was 12 females and 2 males. So, often you have to grow your population to stabilize it and ensure there isn’t an unacceptable loss of genetic diversity over time, even if that genetic diversity is low. If you think back to the math from last week and do a little not so fancy algebra, you can see that genetic deterioration occurs at a rate that is the inverse of genetic retention, which you probably remember is  1- (1/2Ne) Assume that the Española Galapagos tortoise captive population started with an Ne/N ratio of 0.7. Calculate their rate of loss of genetic diversity given their original population size of 14 tortoises (N=14). You will first need to solve for Ne, then plug Ne into the rate of loss of genetic diversity formula. Now let’s work on growing the population.…

In many omnivorous species, it is difficult to know the correlation of individual fitness with the resource distribution of the food available. Would it be enough to measure relative fitnesses of individuals of an omnivorous species in order to know what mode of selection is acting on the omnivore population?  Why or why not?