Exam 16: Community Structure

If one community has a more equitable distribution of individuals among species than another community, it is said to have a high level of species ________.

A null model of community structure assumes that the presence and abundance of species within a community is

Ecologists usually define the species diversity of a community as

The simplest measure of community structure is a count of the number of species present, and is referred to as species ________.

Food webs are useful for depicting ________ interactions among species in which the interaction between two species is mediated by an intermediate species.

In general, the degree of environmental heterogeneity of a community has a ________ effect on the species diversity of that community.

In a forest community, the upper layer is called the ________.

Food webs can be arranged into ________ levels based on whether organisms obtain their nutrition from photosynthesis, from eating plants, or from eating animals.

Explain the difference between a guild and a functional type, and discuss why it may be useful for ecologists to classify species in these ways.

The ________ is a group of plant and animal species that inhabit a given area.

In a food web diagram, groups of species that derive food energy from a similar source are called ________ levels.

The "world is green" hypothesis of Hairston et al. suggests that predators keep herbivore populations in check.

A(n)________ model of community structure assumes that interactions among species have no impact on community structure.

Environmental heterogeneity is often negatively correlated with species diversity across habitats.

(A)________ occurs when predation has a ripple effect on a food web, ultimately affecting primary producers.

A diagram that illustrates the flow of energy, linking several species as prey and predators, is referred to as a

When an indirect interaction is beneficial to two interacting species, the indirect interaction is termed indirect ________.

Species composition does not usually differ much within a local area, such as between a hilltop and a stream bottomland.

Most communities have a few common species and many rare species.

Explain the difference between the organismal concept of communities and the individualistic continuum concept. Which of these concepts best describes the majority of communities? Explain your answer.