Community Ecology

Question 1

Ecological niche

Answer 1

The distinctive lifestyle and role of an organism in a community. It takes into account all abiotic and biotic aspects of the organism’s existence.

Question 2

Fundamental niche

Answer 2

The potential ecological niche for an organism.

Question 3

Realized niche

Answer 3

The niche it actually occupies is its realized niche.

Question 4

Competitive exlusion principle

Answer 4

Two species cannot occupy the same niche in the same community for an indefinite period; one species is excluded by another as a result of competition for a limiting resource.

Question 5

Resource partitioning

Answer 5

The evolution of differences in resource use. It reduces competition between similar species.

Question 6

Character displacement

Answer 6

A way to reduce competition in which their structural, ecological, and behavioral characteristics diverge where their ranges overlap.

Question 7

Symbiosis

Answer 7

It is any intimate or long-term association between two or more species. There are three types of symbiosis.

Question 8

Mutualism

Answer 8

Both species benefit from each other.

Question 9

Commensalism

Answer 9

One organism benefits and the other is unaffected.

Question 10

Keystone species

Answer 10

They are present in relatively small numbers but are crucial in determining the species composition and ecosystem functioning of the entire community.

Question 11

Dominant species

Answer 11

In contrast to keystone species, dominant species greatly affect the community of which they are a part because they are very common.

Question 12

Botton-up processes

Answer 12

If they dominate an ecosystem, the availability of resources such as minerals controls the number of producers, which controls the number of herbivores, which control the number of carnivores.

Question 13

Top-down processes

Answer 13

They regulate ecosystems from the highest trophic level by consumers eating producers. If top-down processes dominate an ecosystem, an increase in the number of top predators cascades down the food web through the herbivores and producers.

Question 14

Species richness

Answer 14

The number of species within a community.

Question 15

Species diversity

Answer 15

A measure of the relative importance of each species within a community based on abundance, productivity or size.

Question 16

Succession

Answer 16

It is the orderly replacement of one community by another.

Question 17

Primary succession

Answer 17

It occurs in an area that has not previously been inhabited.

Question 18

Secondary succession

Answer 18

It begins in an area where there was a pre-existing community and well-formed soil.

Question 19

Intermediate disturbance hypothesis

Answer 19

According to it, species richness is greatest at moderate levels of disturbance, which create a mosaic of habitat patches at different stages of succession.

Question 20

The organismic model

Answer 20

It views a community as a “super-organism” that goes through certain stages of development (succession) toward adulthood (climax). Biological interactions are primarily responsible for species composition and organisms are highly interdependent.

Question 21

Individualistic model

Answer 21

The most supported.
Abiotic environmental factors are the primary determinants of species composition in a community, and organisms are somewhat independent of one another.