Midterm Exam II essay questions

1) What effect do these major evolutionary processes have on genetic variation in natural populations? For each one, write one paragraph that describes the effect and make a sketch of one graph that illustrates your point (3 paragraphs, 3 graphs total).

1. Mutation

2. Drift

3. Gene flow

2) Explain how this scenario is possible including a description of what is occurring at each step. Your answer should have one or two sentences for statements 1-3 and one full paragraph that explains part 4.

1. A population of plants has significant phenotypic variation in petal size.

2. Bees visit plants larger petals more frequently.

3. Plants with more bee visitations produce more seeds in the next generation.

4. Offspring seed germinates and grows up but there is no change in the mean or variance of petal size.