Exam 18: Community Structure　

Explain the shape of the intermediate disturbance hypothesis (IDH) graph. Why does it have the appearance that it does?

Which of the following statements would NOT be true about the species relationship in the figure?

What particular type of environmental conditions favor independent or interdependent communities?

According to the experimental results shown in the figure, what factor best explains the reduction in plant species richness with addition of fertilizer?

Keystone species that are predators in a food web can increase species diversity by

Briefly describe an experiment to test whether species are independent or interdependent on each other for existence.

Which species is restricted to nonserpentine soils?

Shannon's index and Simpson's index are both measurements of a community's level of diversity. What does it mean when, after calculating these two indices for a given community, the results show the Simpson's index = 1, while the Shannon's index = 0?

How would a relatively high proportion of omnivore species in a food web affect the connectedness of the food web?

When Hairston, Smith, and Slobodkin suggested that Earth is green because carnivores depress the populations of herbivores that would otherwise consume most vegetation, they were focusing on _____ control of community structure.

Describe the difference between what is referred to as a direct effect and an indirect effect of species in a food web.

What is a major distinction between direct and indirect effects in a community?

Communities with _____ species are _____ stable.

Which species is restricted to serpentine soils?

You are sampling a stream with a net, collecting 100 macroinvertebrates. You have been told the stream has high richness but low evenness. Which of the following collections would best represent the stream if what you were told is true (assume the different macroinvertebrate types noted are all the same species (e.g., 20 mayflies are all of the same species)?

Which species is restricted to the ecotone between serpentine and nonserpentine soils?

Hairston, Smith, and Slobodkin suggested that Earth is green because carnivores depress the populations of herbivores that would otherwise consume most vegetation. Is this the only possible explanation for the greenness of Earth?

A trophic cascade is an example of _____ effect.

What is a reasonable explanation of the results in the figure?

Which species would you characterize as seemingly unresponsive to changes in soil conditions across the transect?