Exam 19: Species Diversity in Communities

Which statement about zebra mussels in North America is true?

In their tests of the extension of the intermediate disturbance hypothesis in a New England salt marsh, Hacker and Gaines found that in the low intertidal zone, physiological stress was _______ and species diversity was _______.

Which combination of attributes of a community should result in the lowest species richness?

Which one of the following factors most determines the highest possible number of species within a local community?

Which statement about Huston's dynamic equilibrium model is most accurate?

According to Hacker and Gaines's extension of the intermediate disturbance hypothesis, mutualisms and other positive interactions should _______ species diversity, especially at _______ levels of disturbance.

Refer to the figure. The figure depicts Sousa's test of the intermediate disturbance hypothesis. Why is boulder size associated with the level of disturbance? Do these data support or refute the intermediate disturbance hypothesis? Justify your reasoning using the figure.

According to the Menge-Sutherland model, predation affects species richness most significantly at _______ levels of environmental stress or disturbance, and competition is the most important factor at _______ levels of environmental stress or disturbance.

The study of snails by Johnson et al. (2009) found that increasing species richness and

The ability of a community to remain the same in terms of its structure and function despite some perturbation is known as

Refer to the figures. Figure 1 Figure 2 You are evaluating three snail species to determine their overall threat as invasive species to an area. You bring several individuals of each species into your lab to test their tolerance of a range of abiotic and biotic factors. Figure 1 shows how the three snail species respond to differences in average temperature and Figure 2 shows the number of prey and parasite species for each of the species in the new areas, along with how competitive each potential invasive species will be in the new community (higher numbers indicate that the species will be a more successful competitor). -Consider Species B and C and assume that both have successfully invaded a new community. If the native species are similar to the invasive species in their resource use, what type of resource spectrum would you expect for each community that integrates these species? Provide the resource spectrum expected for each of the invaded communities, and justify your predictions.

Refer to the figure. The figure is based on the studies by Robert and John MacArthur. Which figure best describes the relationship between foliage height diversity and species diversity?

What aspect of community membership do humans most impact that leads to invasive species?

The first person to recognize the importance of disturbance in promoting species diversity was _______, who noted that more species persisted on a section of lawn that was mowed regularly than on one that was not mowed.

Refer to the figure. According to this representation of the intermediate disturbance hypothesis, why does diversity decline at more frequent and intense levels of disturbance?

Refer to the figures. Figure 1 Figure 2 Figure 1 depicts Hacker and Gaines' tests of the role of positive interactions in the intermediate disturbance hypothesis and Figure 2 depicts their theoretical model. They experimentally explored the combined species diversity of plants and arthropods in intertidal communities that varied in disturbance and whether a facilitating rush species, Juncus, was present. What conclusions about the role of positive interactions in determining species diversity can you draw from Figure 1? Do they confirm or refute the theoretical predictions of their model? Explain your reasoning.

In Sousa's study of succession in intertidal boulder fields in California, disturbance was _______ proportional to the size of the boulders. The highest level of species richness occurred when disturbance was _______.

Species must pass through several "filters" to become members of a community. Describe these filters and how they can act to exclude invasive species from a community. How do invasive species overcome these filters? Your answer should address how species have historically invaded new areas and how human actions have changed the way these filters affect community membership.

Which statement is not an assumption of the resource partitioning theory?

Refer to the figure. Figure 8 You are studying a new area to determine how disturbances affect species diversity. What could you conclude about the impact of competition if your data exhibited the pattern shown in Figure 8? According to the Menge-Sutherland model, what would this pattern tell you about resource use and recruitment in your study area?