2-22 threat to island populations

Question 1

MacArthur-Wilson Theory of Island
Biogeography

Answer 1

basic philosophy: equilibrium number of species on an island is a balance between colonization rate and extinction rate

Question 2

colonization rate

Answer 2

proportional to distance from source of
colonization, e.g. mainland

Question 3

extinction rate

Answer 3

species-area curve predicts smaller islands have
fewer species due to higher chance of extinction

Question 4

assumption of macarthur-wilson theory

Answer 4

equilibrium number would
conform to species-area curve,
because extinction rate would be
greater on a small island

Question 5

types of evidence for island biogeography theory

Answer 5

Observational
Manipulative
Modeling

Question 6

Observational evidence for island biogeography theory

Answer 6

of reptile and amphibians on Caribbean islands
- number of species on an island can be predicted by island’s area (direct relationship)

Question 7

manipulative evidence for island biogeography theory

Answer 7

Simberloff and Wilson experiments
- experiments: fumigated mangrove islands in florida bay, then looked at recolonization
- result: arthropod populations conform to equilibrium species number as predicted by model

Question 8

modeling evidence for island biogeography theory

Answer 8

modern tests of macarthur and wilson models

Question 9

what are some reasons for background extinction rate?

Answer 9

competition, specialization, restricted geographical range, local catastrophes, small populations, migration losses, low genetic diversity, population decline

Question 10

Barro Colorado Island

Answer 10

in the Panama Canal – isolated by construction of the canal
shortly after 1900. Became the Smithsonian Tropical Research Institute.
Isolation led to loss of biodiversity