Unit 5 Lecture 28 Flashcards
Do larger or smaller islands harbor fewer species?
Small islands harbor fewer species
Which island in the Caribbean do you think has the most species of birds
Dominican Republic+ Haiti (Hispaniola)
What is the species area relationship?
S = cA^z –> LogS = z * LogA + LogC
S = # of species
A = island area
Species-area relationships are _______
Pervasive: happens in all types of species
The breakup of a large landmass into smaller units would lead to what?
Extinction and local extermination
What changes when you add area?
- Number of niches
- Food chain length
- Presence of keystone species
- Inclusion of rare species
Do near, medium, or far islands species richness most strongly relate to island area?
Far typically experiences the steepest slope
of species on an island = to what
new species that immigrate - # species that go extinct
What are the 3 reasonings to Mcarthur and Wilsons prediction that rate of extinction would rise with increasing number of species on an island
- Presence of more species creates a larger pool of potential extinctions
- As number of species increases, population size of each must diminish
- As number of species increases, potential for competitive interactions between species will increase
Once all mainland species are on island, immigration rate =
0
As # of species increases, more ______ competitions
Interspecific: Interspecific competition is the competition between individuals of different species
What happens to equilibrium when a near island gets larger?
S increases
What happens to equilibrium when a far island grows in size?
S decreases slightly
What happens when a far island get smaller?
S decreases significantly
What does species turnover mean?
Extinction is replaced with new immigrant
What was the 3 predictions McArthur and Wilsons made with equilibrium on nearby islands
- 30 bird species
- 40 years to equilibrium
- turnover: 1 species per year (was actually >1)
Explain the study would insect recolonization in Florida keys
- SImberloff chose 2 stands of mangroves as control islands and 6 other as experimental
- Used pesticides to defaunate the islands
- Followed recolonization for 1 year
- Species number stayed constant but composition changed
What was the result of the insect study?
- Near island recovered more than the far island
- Where area was reduced, species richness decreased (richness on control increased slightly)
- Islands with reduced area lost species with each reduction area
Which statement(s) about the theory of island biogeography is FALSE:
A) It can predict species richness of an island based on island area
B) It can predict which species will be on island based on island area
C) It can predict which islands more species based on distance from mainland
D) It relies on assumptions about the relationships between species richness and rates of species extinctions
E) It ignores speciation (evolution of new species)
B
