BIOL 430 (Ecology course from another college), Exam 3                                                   12/1/99

In each section, use only the space provided.  This exam is worth 125 points, 1/8 of your class grade.  You have 50 minutes.  Allocate your time wisely.

A.     Multiple choice.  Choose by circling the most correct answer for each question, unless otherwise specified.  10 questions, 4 points each = 40 points.

1.      Which of the following is a (are) prime determinant(s) of terrestrial biomes?

• a. predation.
• b.      precipitation.
• c. herbivory.
• d. all of the above.

2.      Which of the following types of rank abundance diagrams has the most equitable distribution of individuals among species?

• a. The geometric series.
• b.      The lognormal.
• c. The broken stick.
• d.      The Shannon-Weaver.

3.      Naeem’s Ecotron experiment was flawed because

• a. he only included one trophic level.
• b.      his experiment was flawless.
• c. his low diversity replicates were all composed of the same community.
• d.      his high diversity treatment included only plants that grew low to the ground.

4.      When sampling a community to determine species richness, how do you know if you’ve sampled enough to include a large proportion of the species actually there?

1. a. Species richness reaches an asymptote as sampling effort increases.
2. b.      You don’t; sampling effort and species richness are independent of one another.
3. c. Use the Morisita-Horn similarity index.
4. d.      Use the Simpson’s diversity index.

5.      Enablement is a model of succession which states that 

• a. any species can colonize in any order.
• b.      if species A is present, species B cannot invade.
• c. species A must go extinct before species B can invade.
• d.      species A must invade before species B does.

6.      Which process is predicted to have a greater impact on successional events in severe environments during early succession?

• a. Herbivory.
• b.      Random, stochastic events.
• c. Facilitation.
• d.      Competition.
• e. Both b and c.

7.      A climax, mature forest community can be determined by which of the following?

• a. Comparison of mature tree communities in a forest with the community of saplings underneath.
• b.      Determining Markov replacement probabilities of one species by that species or another species.
• c. By collecting long term data on community structure.
• d.      All of the above could help determine if a forest community is in a mature state.

8.      The target effect

• a. predicts that the colonization of large islands will be greater than that of small islands, assuming equal distance from the mainland.
• b.      predicts that large, far islands will have higher colonization rates than small, near islands.
• c. was part of the original MacArthur-Wilson equilibrium model.
• d.      is all of the above and more.

9.      Which of the following may be the best way to design preserves for maximum biodiversity?

• a. Several small areas of land.
• b.      One large area of land.
• c. Inclusion of habitat corridors.
• d.      All of the above have been hypothesized to promote high species richness.

10.  Which of the following are true? (circle all that are)

• a. There is no relationship between species richness and island size.
• b.      The relationship between S and A has been clearly shown for a variety of taxonomic groups.
• c. The slope of the line relating S to A, z, is constant for all taxa.
• d.      The slope of the line relating S to A is generally lower for habitat islands than oceanic islands for the same taxonomic group.
• e. Organisms with high dispersal abilities are predicted, and have been shown, to have higher values of z than those with low dispersal abilities.

B.        Short Answer: Use only the space provided below each question to answer (45 pts).

1.      Select two biomes we discussed.  List three major characteristics of each biome, including at least one abiotic factor and one aspect of the biota for each.  Compare the two biomes; which one is generally considered to have a more diverse biota, and what is one hypothesis that might explain the difference in diversity?  (21 points).

2.      Three communities, two in forests and one in a field, were sampled for bird species.  The results are shown in the table below.  Calculate the Jaccard community similarity coefficient [C_J = a/(a+b+c)] for all possible comparisons (15 points). Keep in mind the following: 1) you need to construct a matrix for each comparison to determine a, b, & c, and 2) a = the number of species common to both sites. (24 points total: 15 points, plus each question below is worth 3 points).

a. Which two communities are most similar?

b.      Which species might be considered habitat generalists? 

c. What type of index might be a better one to use in this situation?

C.        Outline of an essay (40 points). Use the space below to answer.  Do not write an essay; simply make an outline.  The third essay will come later and will be optional.

Consider the two key ecological concepts of succession and island biogeography.  Consider how the Facilitation model of succession might apply to two processes of the MacArthur-Wilson “Theory” of Island Biogeography, as it applies to a newly formed oceanic island.  Name each of the two common processes, and clearly outline, including examples, how facilitation could be involved in community development on the new island.  If you feel the two concepts are unrelated, support that argument by outlining processes that are specific to each of the two concepts and unrelated to each other.

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