BIOL 430 (Ecology course from another college), Exam 2                                                                                            12/16/1999

In each section, use only the space provided and read directions.  This exam is worth 200 points.

A.        Multiple choice.  Choose by circling the most correct answer for each question, unless otherwise specified.  21 questions, 3 points each = 63 points.

1.      Allopatric speciation is a speciation event that arises from

1. temporal separation of two populations.
2. geographic separation of two populations.
3. an individual having parents of different species.
4. reproductive isolation of two populations.

2.      Which of the following best describes the realized niche of an organism?

1. All the biotic factors that determine where a species can live.
2. It is smaller than the fundamental niche.
3. It may be determined by transplant experiments.
4. All of the above describe the realized niche.

3.      Diversity is best measured by which of the following indices?

1. Simple matching coefficient.
2. Jaccard index.
3. Shannon index.
4. All of the above measure diversity adequately.

4.      In the lab, we found that diversity in the forest of Kirby Park Natural Area was higher than in stream insects of Harvey’s Creek because

1. trees were keyed out to the species, while insects were only keyed out to the order.
2. tree species richness was higher than insect species richness.
3. it was not different, they were the same.
4. we used a different index of diversity.

5.      Life history variation is related to succession by which of the following statements?

1. Early successional species tend to be K-selected.
2. Early successional species tend to be competitive.
3. Late successional species tend to be r-selected.
4. Late successional species tend to be weak competitors.
5. None of the above are true.

6.      Evolution of species on islands is more likely under which of the following sets of conditions?

1. Small, close islands with persistent populations and high immigration.
2. Small, far islands with small populations that don’t persist long, and low immigration.
3. Large, far islands with persistent populations and low immigration.
4. Large, close islands with persistent populations and high immigration.

7.      Abiotic factors may affect the structure of food webs by

1. Abiotic factors do not affect food webs.
2. causing top predators to have more biomass than herbivores.
3. increasing connectance to 1.0.
4. limiting the population size of a primary producer.

8.      Interactions between plants and their pollinators is

1. a mutualism.
2. an example of energy flow from one trophic level to another.
3. the result of coevolution.
4. all of the above are true.

9.      Species richness

1. is equal to the number of links in a food web.
2. increases as one travels towards the north or south poles.
3. is equal to the number of species in a sample or community.
4. is equal to the economic value of a species.

10.  David Tilman’s experiments on plots of grassland in Minnesota examined the effects of species richness on ecosystem function.  One major pattern that was revealed by this experiment was

1. the number of species had nothing to do with any ecosystem function.
2. species-rich plots were more resistant to and recovered more quickly from drought.
3. that productivity decreased with diversity because no single species was allowed to dominate and grow to a large size.
4. the number of species was related to uptake of carbon from the soil.

11.  The tolerance model of succession was developed as a response to

1. the inhibition and facilitation models.
2. the observation that many species are tolerant of the presence of competitors.
3. patterns of mutualists in communities.
4. observations of successional patterns in deserts.

12.  What is the relationship between succession and biodiversity?

1. Biodiversity may be higher in slighly disturbed habitats because secondary succession allows early successional species to invade and late successional species to also be present.
2. There is no relationship between the two.
3. During primary succession, biodiversity is at its highest in very early stages.
4. Succession does not occur in communities with high biodiversity because those communities are buffered against disturbance.

13.  Which of the following may limit primary productivity?

1. Nitrogen.
2. Light.
3. Water.
4. Temperature.
5. All of the above.

14.  Food webs reported in early ecological literature generally show

1. low degrees of omnivory and loops, and high numbers of links per species.
2. low degrees of omnivory and loops, and low numbers of links per species.
3. high degrees of omnivory, no loops, and medium numbers of links per species.
4. high degrees of omnivory, low degrees of loops, and low numbers of links per species.

15.  The target effect states that

1. the colonization of large islands will be greater than that of small islands, assuming equal distance from the mainland.
2. near islands will have lower extinction rates than far islands, given the same size.
3. the original MacArthur-Wilson equilibrium model was right on target.
4. none of the above is true.

16.  Energy transfer from one trophic level to another is

1. between 0.5 and 3.5%.
2. around 10%.
3. around 1%.
4. around 25%.

17.  Secondary productivity is the amount of biomass produced by

1. secondary carnivores.
2. secondary plants in communities.
3. herbivores, detritivores, and carnivores.
4. detritivores.

18.  The efficiency of transferring the energy in sunlight that hits Earth into chemical energy via the process of photosynthesis is

1. slightly higher for some communities than others.
2. generally around 0.5 – 3.5%.
3. dependent upon the availability of other limiting factors, such as soil nitrogen.
4. all of the above.

19.  Which of the following is NOT a generalization about food webs?

1. Linkage density is often constant, except in very large webs.
2. Linkage strength is almost always stronger in lower trophic levels.
3. Disturbance decreases average chain length.
4. Chains are shorter in two dimensional habitats.

20.  Connectance is a measure of

1. the potential number of links in a food web.
2. the actual number of links compared to the potential number of links in a food web.
3. trophic level transfer efficiency.
4. park reserve habitat corridors.

B.        True or False (3 points each = 30 points).

______ 1.        An ecosystem engineer makes resources more available to other organisms.

______ 2.        The amount of resources available to competing species may affect the strength of a competitive interaction.

______ 3.        Early successional species usually have K-selected life history characteristics.

______ 4.        Evolution is both fact and theory.

______ 5.        Island Biogeography, as outlined by MacArthur and Wilson, is supported by some experimental evidence.

______ 6.        The diversity of a community depends on primary productivity only.

______ 7.        Boreal forests occur only where temperatures are never below 0^oC and precipitation is below 15 cm per year.

______ 8.        Tropical rainforests are multi-layered habitats.

______ 9.        As communities are sampled more intensively, the number of new species found per sample decreases, as does the information regarding the food web in that community.

______ 10.      Abiotic factors can determine the limits of individual species, and are primary determinants of biomes.

C.        Short Answer, Part I: Choose 5 out of the following 7 to answer.  Use only the space provided below each question to answer (12 points each = 60 points total).

1.      Compare and contrast the biological species concept and the phylogenetic species concept.

2.      Three species of insect-eating birds are found to coexist in a habitat.  They all apparently forage for insects exclusively on oak trees.  What are two mechanisms that could explain this apparent coexistence (6 points/mechanism)?

3.      List three types of diversity (NOT diversity indices) that can be measured in a community to express the level of biodiversity.

4.      What are two fundamental problems with generalizations about food webs?

5.      Choose any concept we learned in Ecosystems (except those related to the latitudinal diversity gradient) and relate it to energy flow through ecosystems.

6.      Relate any one hypothesis of the latitudinal diversity gradient to food webs and energy flow.

7.      Explain how altitude affects the presence of particular biomes in mountainous regions and describe the distribution of biomes as one ascends up a mountain.

D.        Short Answer, Part II.  One question, 25 points.

1.         Select one biome.  Select five concepts, hypotheses, or topics that we learned about in class and relate them to characteristics of the biome (abiotic or biotic).  Write no more than one sentence per characteristic (5 points per concept/hypothesis = 25 points).

E.         Matching.  Match the term on the left with the appropriate descriptor on the right (2 points each = 22 points).

______ 1.        Primary succession a.         The number of trophic levels in a web.

______ 2.        Community web                                  b.         The intensity of an interaction between                                                                                                two species.

______ 3.        Secondary productivity                         c.         A group of functionally similar organisms within a trophic level.

______ 4.        Guild                                                    d.         Plants invade an area where no plants                                                                                                had been before.

______ 5.        Tolerance                                             e.         A group of species that feed on one                                                                                                 organism and the species that feed on them.

______ 6.        Secondary succession                           f.          A group of species living in the same                                                                                                 place at the same time.

______ 7.        Chain length                                          g.         Any species can colonize, and climax community is reached in orderly fashion.

______ 8.        Primary productivity                              h.         The production of biomass from energy                                                                                                of sunlight.

______ 9.        Linkage strength                                   i.          A group of species and their interactions                                                                                              within a defined area or habitat.

______ 10.      Community                                           j.          Process that occurs after a disturbance.

______ 11.      Source web                                          k.         Creation of non-plant biomass.

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