Community Ecology 2 - Predation and Community

Question 1

Species Diversity in a Community

Answer 1

1. Richness
2. Evenness

Question 2

Species Richness (S)

Answer 2

simply a count of the number of species in a community

Question 3

Species Evenness

Answer 3

the relative abundance of species in a community (how evenly individuals are distributed among species)

Question 4

Community Stability

Answer 4

• communities are not random assemblages of species
• they are non-random because of interspecific interactions

Question 5

Keystone Species

Answer 5

species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically
- serves as an unintentional force for stability of a complex set of community interactions
- usually neither the most numerous nor best competitor for resources in an ecosystem

Question 6

MacArthur + Wilson: Islands

Answer 6

1. more isolated island have lower immigration rates
2. larger islands have lower “extinction” rates (loss of the species to the island). One way that a species can remain on the island is to re-migrate, which is more likely to happen by change on larger islands

Question 7

Equilibrium Number - S-hat

Answer 7

the intersection of immigration and extinction rates for an island predict an equilibrium number of species, S-hat, assuming island size and distance from mainland