Chapter 15

  1. A group of interacting species that occur together at the same place and time is known as a(n)
  2. Despite having a relatively small biomass, populations of grizzly bears often have strong effects on their communities. The grizzly bear is therefore an example of a
    keystone species.
  3. The lowest possible value of the Shannon index is _______. Low values indicate _______ species diversity.
    0; low
  4. The Shannon index is determined by applying the _______ to the proportion of each species in a community, multiplying it by the proportion once again, and then summing those values.
    natural logarithm
  5. In a food chain, secondary consumers are _______ primary producers.
    two levels above
  6. The trophic facilitation phenomenon described by Hacker and colleagues involves direct interactions between two plant species in the form of _______, with indirect effects benefiting a _______ of one of the plants.
    commensalism; herbivore
  7. The studies by Powers and colleagues of northern California river ecosystems showed
    that the strengths of species interactions can vary depending on the environmental context.
  8. Suppose you wanted to determine whether you had adequately sampled the species richness of a given community. Which of the following results would most likely lead to the conclusion that more sampling was needed to assess the species richness?
    A linear species accumulation curve
  9. What is the fundamental distinction between a competitive network and a competitive hierarchy?
    In competitive hierarchies, one species dominates the interaction; in competitive networks, no single species dominates.
  10. In the classic trophic cascade, sea otters feed on sea urchins, which in turn feed on kelp. Via indirect effects, a reduction in kelp abundance would likely _______ the abundance of sea otters. A reduction in sea otter abundance would likely _______ the abundance of kelp.
    decrease; decrease
Card Set
Chapter 15
Chapter 15