Unit 2: Community Characteristics & Dynamics

Question 1

What is Species Richness?

Answer 1

number of different species in a community

Question 2

What is Species Abundance?

Answer 2

(species evenness) absolute population size of a particular species relative to the population size of other species within the community

Question 3

If one species dominates another, there will be a ____ species abundance score.

Answer 3

low

Question 4

What is Species Diversity?

Answer 4

diversity metric that incorporates both richness and evenness

Question 5

If there is higher evenness, there will be a _____ diversity score

Answer 5

higher

Question 6

What is a Food Web?

Answer 6

the feeding relationships among organisms in a community

Question 7

What is a Food Chain?

Answer 7

a single path of an organism in a food web

Question 8

What is a Trophic Level?

Answer 8

the position of an organism in a food chain; usually depicted as a triangle, with the primary producers at the bottom as population size and energy levels go down as you go up the food chain

Question 9

What is a Foundation Species?

Answer 9

species which often forms the major structural portion of the habitat; usually the primary producers (e.g. coral reefs)

Question 10

What is a Keystone Species?

Answer 10

species whose presences is key to maintaining biodiversity in an ecosystem and to upholding an ecological community’s structure; not most abundant, but most necessary to hold biodiversity

Question 11

What is Succession?

Answer 11

sequence of changes in communities occupying an area after an environmental disturbance or the creation of a new substrate

Question 12

At what stage of succession, do species alter the environment?

Answer 12

each stage, in which a new species in introduced or changes (e.g. as a new tree grows in, less sunlight becomes available)

Question 13

Succession is impossible to predict. True of False?

Answer 13

False, the changes of succession are often predictable

Question 14

What are the 3 ways an existing species may affect the species which follows them in introduction?

Answer 14

1. Facilitation: conditions become favorable
2. Tolerance: no effect
3. Inhibitation: hinders establishment

Question 15

What is Climax Community?

Answer 15

the final stage of succession, where a stable community is formed by a characteristic assortment of plant and animal species; species are tolerant of competition with each other

Question 16

What are the 2 types of Succession?

Answer 16

1. Primary Succession
2. Secondary Succession

Question 17

What is Primary Succession?

Answer 17

succession on land that previously had no life

Question 18

What is Secondary Succession?

Answer 18

succession in response to environmental disturbances that move a community away from its equilibrium

Question 19

What is a Pioneer Species?

Answer 19

1st species to appear in primary and secondary succession

Question 20

What are characteristic of a pioneer species?

Answer 20

• “weedy”
• high rmax
• devote more energy to reproduction than competitive ability