CH 54 Mastering

EXAMPLE OF DIRECTIONAL SELECTION 2. DISRUPTIVE SELECTION 3. STABILIZING SELECTION

1. dark rocks only, dark fur, more individuals with darker fur 2. Dark rocks and light rocks, dark fur and light fur, and more individuals with dark fur or light fur and fewer with intermediate colors 3. Rocks of intermediate color, fur of intermediate color, more individuals with intermediate fur color.

The term used to describe a harmless organism resembling a harmful one is _____.

Batesian Mimicry

An egret eats insects stirred up by grazing animals. Which of these terms applies to the relationship between the egret and the grazing animal?

Commensalism

Humans and sharks both eat fish. Which of these terms applies to the relationship between the human and the shark?

Competition

An earthworm that feeds on the remains of plants and animals is acting as a _____.

Detritivore. The earthworm is feeding on the remains of dead organisms.

According to the principle of competitive exclusion, two species cannot continue to occupy the same _____.

Ecological Niche

Which of the following best illustrates ecological succession?

Grass grows on a sand dune, is replaced by shrubs, and then by trees.

Mutualism

In mutualism, both members of the species pair benefit; in this case the human is healthier and the pet is getting room and board.

Cellulose-digesting microorganisms live in the guts of termites and ruminant mammals. The microorganisms have a home and food, and their hosts gain more nutrition from their meals. This relationship is an example of _____.

Mutualism

Humans who have pets tend to be healthier than humans who do not have pets. Which of these terms applies to the relationship between a human and a pet?

Mutualism

Which of these terms applies to the relationship between a dog and a blood-sucking tick?

Paratism

A human eats a deer. Which of these terms applies to the relationship between the human and the deer?

Predation

When a human eats a steak, the human is acting as a _____.

Secondary consumer. By feeding on a primary consumer, the human is acting as a secondary consumer.

A human who just ate a hamburger is eaten by a shark while swimming. The shark is acting as a _____.

Tertiary consumer. The shark that ate the human that ate the cow that ate the grass is the tertiary consumer.

In Batesian mimicry,

a palatable or harmless species mimics an unpalatable or harmful model.

An organism's "trophic level" refers to _____.

its food source

In commensalism

one member of the species pair benefits and the other is unaffected; in this case the egret is getting a meal and the grazing animals are unaffected.

The competitive exclusion principle states that when the ?

populations of two species compete for the same limited resources, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other species.

A cow eating grass is an example of a _____.

primary consumer

In an ecosystem, phytoplankton are _____.

producers. Autotrophs, such as phytoplankton, are producers.

Keystone species are those species _____.

whose absence would cause major disruption in a community