Exam 23: Ecological Communities

A(n)____________________ is a single sequence of who eats whom in a community.

Communities never recover from disturbances caused by humans.

Which of the following best characterizes humans' method of obtaining energy?

Coevolution often occurs when natural selection produces evolutionary change in predator and prey populations; a good example is

Communities change with respect to several timescales; an example of long-term change would be the

The fact that some organisms live in herds or flocks in order to protect themselves from predators is an example of ____________________ modification.

Organisms that eat producers are known as

The removal of a keystone species from a community usually results in

Antibiotic therapy sometimes reduces the population of gut-inhabiting microorganisms. Bloating and diarrhea often follow until the populations reestablish themselves. This observation suggests that these microorganisms participate in a(n)_____ relationship with humans.

Without pollinator mutualism, agricultural productivity could fall significantly.

Burning of fossil fuels may affect climate but not communities.

Pathogens are considered a special type of parasite because they

Which of the following statements is false?

As the figure below illustrates, the distribution of numerous intertidal organisms is restricted to bands or zones. The upper limit to the zone is determined by tolerance to physical factors like desiccation, whereas the lower boundary is determined by a biological interaction such as competition. What could account for the lower limit for Semibalanus?

Certain species of squirrels and acorn woodpeckers both eat acorns. In forests without squirrels, the density of acorn woodpeckers averages 100 per square kilometer, whereas in forests with squirrels the density of acorn woodpeckers is roughly halved. This reduced density most probably results from

A tapeworm is living in the intestine of a human and absorbing nutrients. This relationship is one of

Into which category would a human be assigned when eating pepperoni pizza?

A species can participate in several symbiotic relationships simultaneously; for example, the invasive fire tree competes with native vegetation for soil nutrients and maintains a mutualistic relationship with root bacteria.

Which of the following symbols represents a mutualistic relationship?

____________________ are animals eaten by other animals.