BIO 313. Evolution. EXAM 2, Summer 1997.

Dr. Bruce W. Grant, office Kirk 200, 610-499-4017
Dr. David Coughlin, office Kirk 206, 610-499-4025
Department of Biology, Widener University
Chester, PA, 19013

Last Updated: 31 July 1997

Exam Cover Page. BIO 313 - EXAM 2, Thursday, August 7, 1997.

This EXAM is in Two Parts:               I.  Short Answer Questions (90 points).  DO ANY 6 OF THESE (15 points each).

              II.  Longer Answer Questions (120 points).  DO ANY 4 OF THESE (30 points each).
 

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    Short Answer Questions. BIO 313 - EXAM 2, Thursday, August 7, 1997.

    I.  Short Answer Questions (15 points each).  DO ANY 6 OF THESE.  
    1. Please list and briefly define 5 microevolutionary forces.

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    2. A clear case of meiotic drive is the segregation disorder allele in some Baja and Wisconsin fruit flies, however there are very few other cases of meiotic drive in nature despite its potency as a microevolutionary force.  Why is meiotic drive so rarely documented?

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    3. Under what conditions would Hardy-Weinberg equilibrium occur and exactly what is at equilibrium when it does occur?

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    4. What are the strengths and weaknesses of phenetic classification versus phylogenetic  classification (or cladistics)?Please define each, describe how each proceeds, and explain the questions each can best answer.

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    5. What is the “molecular clock” and what are some of the major lines of evidence for and opposed to its use in constructing evolutionary phylogenies?

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    6. What is a species?  What is the difference between “phenetic” and “biological” concepts of a species?

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    7. Why might habitat fragmentation and species isolation lead to lower biodiversity in an ecological scale of time (i.e. thousands of years), but higher biodiversity over an evolutionary scale of time (i.e. millions of years)?

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    8. Why might humans, Homo sapiens, have evolved “naked” skin?  Why might there have been selection for body hair loss by our hominid ancestors?  Please explain as many different hypotheses as you can document.

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    9. What is an “effective population size” and why is this important??  Please explain this concept and explain why it is a much more important parameter than is the actual population size (e.g. measurable from a random mark-recapture study) in understanding how to manage the genetic resources of a population.

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    10. What is the main goal of “population viability analysis” and what types of data are needed to determine the so-called “minimum viable population”?

    Longer Answer Questions. BIO 313 - EXAM 2, Thursday, August 7, 1997.

    II.  Longer Answer Questions: CHOOSE ANY 4 (30 points each).
    1. This question will assess your understanding of Natural Selection.
        2. a.  What are the three conditions for evolution to occur by natural selection?
        b.  Please briefly define directional, disruptive and stabilizing selection.
        c.  Please explain in your own words why the rate of evolution under directional selection should be proportional to the genetic variance (in particular the additive genetic variance) in a population.
        d.  What is “adaptive plasticity”?  (Hint:  think about the term for the genotype environment interaction in the equation VP = VG + VE + VE*G)
       
    2. This question will assess your understanding of coevolution.
        3. a.  Please briefly define coevolution:
        b.  Please briefly explain two ways in which coevolution differs from evolution.
        c.  Offer and briefly explain a biological example of how coevolution could have resulted from selection due to competition.
        d.  Offer and briefly explain a biological example of how coevolution could have resulted from selection due to a predator prey interaction.
        e.  Offer and briefly explain a biological example of how coevolution could have resulted from selection due to mutualism.
       
    3. When did the five mass extinctions occur in the last 500 million years of Earth’s history?  Pick any one of them and explain in detail what happened.  What are the likely causes?  Who went extinct, who didn’t?  Who underwent rapid adaptive radiation following the extinction event?  Lastly, compare the magnitude (rates and identities of taxa lost) of your chosen extinction event to the 6th mass extinction event currently underway today.

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    4. Steven J. Gould and others noticed that sometimes within lineages of fossilized life forms long periods of gradual change occurred (termed phyletic gradualism) whereas in other lineages there were long periods of stasis punctuated by rapid change (termed punctuated equilibrium).  What are some of the best data sets illustrating these two types of rates of evolutionary change within representative clades?  Explain possible mechanisms for each type of rate.  And lastly, speculate upon possible resolutions to this debate about which rate is more prevalent.

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    5. One of the key requirements of many mechanisms of speciation is a means to guarantee reproductive isolation that would allow divergence to continue.  There are two basic types of reproductive isolating mechanisms - premating and postmating.  Please define, explain, and give examples of each type of isolating mechanism.

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    6. Why did humans evolve such large brains?  What are some of the better explanations for this trait?  (Note: there are several reasonable and very different theories - your task is to find and explain them.)

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    7. What are the specific lines of scientific evidence that unequivocally refute the core tenets of “creationism” (or “creation science” as some call it) and thereby expose this body of writing to be religious ideology thinly masked by junk science?

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    Copyright: Bruce W. Grant, 1997.