Ch. 37 Bio 102

A community is composed of

potentially interacting populations of different kinds of organisms.

When two different populations in a community benefit from their relationship with each other, the result is called ____

Mutualism

Which of the following is an example of predation?

a hawk swooping down quickly to capture, kill, and eat a prairie king snake

The sum total of a population's use of the biotic and abiotic resources of its habitat constitutes its ___.

Niche

In an ecosystem, you would expect to find interspecific competition between

populations of two species that occupy the same niche

If an overlap develops between the ranges of two closely related species, and if the species occupy the same niche in the zone of overlap, what will probably happen in the zone of overlap?

One species will take over most or all of the zone of overlap.

Camouflage typically evolves as a result of ___.

predation

One mechanism that prey populations evolve to avoid predation is

chemical defenses.

Some herbivore-plant interactions evolved through a series of reciprocal evolutionary adaptations in both species. The process is called ___.

Coevolution

Most plants have a variety of chemicals, spines, and thorns because the plants

cannot run away from herbivores.

The prokaryotes that cause tooth decay have a ________ relationship with humans.

parasitic

Within an ecosystem, a tree is a ___.

producer

On Earth, most organic molecules are produced by

photosynthesis

In a hypothetical food chain consisting of grass, grasshoppers, sparrows, and hawks, the grasshoppers are

primary consumers

In a food chain consisting of phytoplankton → zooplankton → fish → fishermen, the fishermen are

tertiary consumers.

Organisms that digest molecules in organic material and convert them into inorganic forms are

decomposers

Which of the following statements regarding food webs is true?

Several species of primary consumers may feed on the same species of producer.

The number of species in a community is called the

species richness.

We expect that a keystone species that is a predator will

maintain the species diversity in a community.

During ecological succession, the species composition of a plant community generally

changes gradually because each species responds differently to the changing environment.

When a New England farm is abandoned, its formerly plowed fields first become weedy meadows, then shrubby areas, and finally forest. This sequence of plant communities is an example of

secondary succession.

Non-native species that are introduced in new environments, spread far beyond the original point of introduction, and cause damage are called

invasive species.

The flow of ________ into ecosystems occurs in one direction only, while ________ are recycled within the ecosystem itself.

energy . . . chemicals

In an average ecosystem, about how much energy is present in the organisms at a given trophic level compared to the organisms at the next higher trophic level?

ten times as much

Which of the following substances is cycled between organic matter and abiotic reservoirs?

carbon

Carbon mainly cycles between the biotic and abiotic worlds through the processes of

cellular respiration and photosynthesis.

Which of the following statements about the nitrogen cycle is true?

The nitrogen cycle requires different types of bacteria.

Denitrifying bacteria convert ________ to ________.

nitrates . . . nitrogen gas