Exam 17: Community Structure

Within a community,a group of species that carries out similar functions or exploits the same resource is called a(n)________.

Which description is true for most communities?

A(n)________ is a type of community with relatively consistent species composition; a uniform,general appearance; and a distribution that is characteristic of a particular habitat.

Which statement best describes a keystone species?

When an ecologist compares the diversity of different communities by counting the number of species within each community,the measure of diversity being used is called

The species within a guild are unlikely to interact with one another.

Every community has an associated vertical structure.

Some aquatic communities are defined by physical features of the abiotic environment rather than by the dominant organisms.

The form and structure of terrestrial communities are defined more by the plants than the animals present.

When a single or a few species are most prevalent in a community,the species are called ________.

________ index (D)represents the probability that two individuals randomly selected from a sample will belong to the same species.

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

The layer of a forest in which decomposition takes place and mineral nutrients are released for reuse by plants is called the

If a forest canopy is dense and closed,the understory and shrub layers tend to be well developed.

In aquatic habitats,the bottom zone where decomposition is most active is referred to as the ________ zone.

During the summer,the bottom,cold layer of dense water in a well-stratified lake is called the ________.

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

In a sandy beach community,ghost crabs and beach flies occur within

In a forest community,the layer containing tall shrubs,small trees,and young trees is called the ________.

The percentage of individuals in a community that belong to one species is called the relative ________ of that species.