Review the process of natural selection. Use the steps to explain how PCB resistance became so common among tomcod in the Hudson. Be sure to include the terms mutation, fitness, selective pressure, and adaptation in your explanation.

https://evolution.berkeley.edu/evolibrary/news/110301_pcbresistantcod (ARTICLE LINK)

QUESTIONS:

1. Review the process of natural selection. Use the steps to explain how PCB resistance became so common among tomcod in the Hudson. Be sure to include the terms mutation, fitness, selective pressure, and adaptation in your explanation.

2. In this blog post, the author describes the tomcod as "a quick learner" because of the population's adaptation to PCBs. Is "learning" an accurate way to describe the change in the Hudson River tomcod population? Why or why not?

3. The data shown on the map above support the hypothesis that natural selection for PCB resistance has occurred among tomcod in the Hudson. What sort of evidence regarding gene frequencies in different populations would argue against this hypothesis (i.e., imagine what the scientists would have observed in this study if natural selection on the AHR gene had not occurred among Hudson River tomcod)?

4. Why is it not accurate to assume that species that feed on tomcod will also evolve resistance to PCBs. What misconception about the process of evolution by natural selection is highlighted under the thinking that natural selection “provides organisms with the traits they ‘need’ to survive”? Be sure to explain why this misconception is incorrect using what you know about how natural selection operates.