Factors of Community Structure

Question 1

Keystone predation

Answer 1

predator has an effect on the food web that is disproportionate to its abundance

Question 2

indirect effect

Answer 2

an organism influences abundance of another organism through a third species of resource

Question 3

consumptive competition

Answer 3

competition that occurs when two species consume the same resources

Question 4

apparent competition

Answer 4

two species negatively affect each other due to a shared predator

Question 5

apparent mutualism

Answer 5

two species positively influencing each other through indirect effect

Question 6

bottom up control

Answer 6

the productivity and abundance of populations at any given trophic level are controlled/limited by the productivity and abundance of populations in the trophic level below them

Question 7

top down control

Answer 7

occurs when predator populations can control the abundance of prey species

Question 8

trophic cascade

Answer 8

loss of predator leads to loss of plant, changes in one trophic level cascads to lower trophic levels

Question 9

diffuse effects in food webs

Answer 9

in diverse food web, hard to predict how changes in one species abundance will influence other species due to indirct effects

Question 10

environmental variability/heterogeneity

Answer 10

positive relationship between heterogeneity and diversity. environmental conditions vary spatially to increase diversity by supporting a wide array of specie. increased vertical structure means more resources and living space and a greater diversity of habitats

Question 11

ecosystem engineers

Answer 11

species that modify the environment in some way that changes composition(e.g beavers)