Geology 105 - Paleontology
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Exam #1 Potential Questions

Short Answer:

  1. Describe two of the ways in which organisms are preserved in an altered state. What organisms are likely to be fossilized in each of these ways?
  2. Apply the four preservation filters (environmental, mechanical, biological, chemical) to each of these organisms to evaluate the preservation potential of each. Explain your reasoning for each answer:
  3. What is the difference between natural selection and evolution? Be sure to define each one in your answer.
  4. What are the necessary conditions for natural selection to occur?
  5. Describe two mechanisms that can create genetic change over time without natural selection.
  6. Describe at least two mechanisms by which a small amount of genetic change could lead to a large change in the physical structure of organisms.
  7. Explain the difference between a biospecies and morphospecies.
  8. Examine the collection of fossils before you. They are all the same mophospecies. When we call these members of the same species, what assumptions are we making? What information do we have in defining biological species that we do not have in defining morphological species?
  9. Examine the fossil lineage you have been given (to be provided). Do you see evidence for punctuated equilibrium, phyletic gradualism, or some combination of the two? Define the two patterns of evolution, then cite specifically where you see either or both of them in the lineage.
  10. Describe at least four mechanisms of reproductive isolation, and give an example of each.
  11. Under what circumstances may I choose the name of a new species? What must I do to make that name "official"?


1. This graph shows the numbers of families (like species, genus, family, etc) of marine invertebrates that we have measured over geologic time. 

Generic Diversity curve

2. We are often told that the human appendix is a vestigal organ with no apparent function. Explain the persistence of the appendix in at least three different ways, including explanations that invoke adaptation, and those which do NOT require natural selection. (Note: success on this question does not require Googling to find explanations for the appendix.  I do not care whether your explanation is similar to conventional thinking about the appendix.  I want to see that you can construct explanations that invoke adaptation, and that invoke other mechanisms, no matter how far-fetched your explanation is.  I'm trying to see if you understand adaptation and the other mechanisms that do not depend on adaptation).

3. One of the greatest puzzles in evolutionary biology is how complex or specialized structures evolve, especially structures that are not functional in a simpler form. For example, some dung beetles are camouflaged by looking like the excrement they eat. It's hard to imagine how this trait could evolve gradually. As Stephen Jay Gould has pointed out, there's not much adaptive advantage in looking 10% like a turd. Describe three different mechanisms by which this trait could have evolved. (Again, do not spend time Googling dung beetles.  I want to see if you understand the mechanisms for the evolution of complex structures, NOT whether you found someone elese's ideas about dung beetles).

4. Phyletic gradualism and punctuated equilibrium represent different models of the pace and tempo of speciation. Each model is more consistent with a particular view of how environments change and about how speciation occurs. Explain each model of speciation, including what it implies about environments, allopatric and sympatric speciation.