Comments about Problem Set 1

Here are some suggestions to make your essay question answers better.

· I care about whether you understand concepts in this course. If you have not demonstrated to me that you understand a concept, I will ask you to rewrite the question or talk to me about your answer. If you can demonstrate to me that you have increased your understanding or have articulated your idea more clearly, I will regrade your assignment so that you can get a maximum of half of your lost points back.

· Avoid making statements as if they are fact if you don’t know whether or not it has been tested. An example is stating that Tansy is adapted to the lake or ridge environment. We don’t know that for sure but we can make hypotheses about it and then design experiments to test those hypotheses. These kinds of comments should be stated as hypotheses and can be supported with your own personal observations.

· Avoid vague statements without a supporting explanation. For example…

Could be improved:

“Temperature and rainfall effects where you find Tansy.”

Why is this piece of information relevant? Why would temp and rainfall be expected to have an effect?

Better phrasing:

“Tansy is widespread throughout the U.S. which suggests that it can adapt to different climates.”

· If I say “flesh out” or “not complete” as a comment, that means that you have not provided a sufficient explanation to support your statement.

· If I say “let’s talk about this,” don’t freak out. It just means that there is a miscommunication and I cannot diagnose the problem without a direct conversation. Just catch me after class.

· If I want a list, I will ask for a list. Otherwise, assume that you should explain your answers in complete sentence and paragraph form.

Good answers for Questions 1, 2, 4 and 5

Question 1

1. Broad ecological amplitude – can tolerate a wide range of conditions
2. Lack of native herbivores
3. Perennial habit allows persistence through changing environmental conditions
4. Clonal and sexual reproduction
5. Human-mediated dispersal as a garden plant

Question 2

1. Greater genetic diversity because it is partitioned among populations that occur in different environments.
2. Greater genetic diversity because relaxed selection allows genetic diversity to accumulate.
3. Greater genetic diversity because perennial lifestyle allows multiple rounds of sexual reproduction in an individual’s lifetime.
4. Greater or lesser depending upon whether selection is diversifying or in a single direction.
5. Great genetic diversity because lack of herbivory leads to larger population size.
6. Less diversity because of natural selection.
7. Less diversity because of clonal growth.

Question 4

1. No – populations are too close to one another. – no barrier to gene flow
2. Depends – can’t tell based on our data. Slight differences we observed could be all environmentally induced.
3. No – any difference we found can be attributed to sampling error.
4. Yes – there may be differences given that the environments differ so much. However, our data was fraught with error and we didn’t have a big enough sample size.
5. Can’t say because we don’t know anything about the history of these particular populations.

Question 5

1. Genetic differences among populations
2. Environmentally induced variation among populations, climate and disturbance
3. Observer bias
4. Small sample size – sampling error
5. nonrandom sampling