Unit 5 Lecture 28

Question 1

Do larger or smaller islands harbor fewer species?

Answer 1

Small islands harbor fewer species

Question 2

Which island in the Caribbean do you think has the most species of birds

Answer 2

Dominican Republic+ Haiti (Hispaniola)

Question 3

What is the species area relationship?

Answer 3

S = cA^z –> LogS = z * LogA + LogC

S = # of species
A = island area

Question 4

Species-area relationships are _______

Answer 4

Pervasive: happens in all types of species

Question 5

The breakup of a large landmass into smaller units would lead to what?

Answer 5

Extinction and local extermination

Question 6

What changes when you add area?

Answer 6

• Number of niches
• Food chain length
• Presence of keystone species
• Inclusion of rare species

Question 7

Do near, medium, or far islands species richness most strongly relate to island area?

Answer 7

Far typically experiences the steepest slope

Question 8

of species on an island = to what

Answer 8

new species that immigrate - # species that go extinct

Question 9

What are the 3 reasonings to Mcarthur and Wilsons prediction that rate of extinction would rise with increasing number of species on an island

Answer 9

1. Presence of more species creates a larger pool of potential extinctions
2. As number of species increases, population size of each must diminish
3. As number of species increases, potential for competitive interactions between species will increase

Question 10

Once all mainland species are on island, immigration rate =

Answer 10

0

Question 11

As # of species increases, more ______ competitions

Answer 11

Interspecific: Interspecific competition is the competition between individuals of different species

Question 12

What happens to equilibrium when a near island gets larger?

Answer 12

S increases

Question 13

What happens to equilibrium when a far island grows in size?

Answer 13

S decreases slightly

Question 14

What happens when a far island get smaller?

Answer 14

S decreases significantly

Question 15

What does species turnover mean?

Answer 15

Extinction is replaced with new immigrant

Question 16

What was the 3 predictions McArthur and Wilsons made with equilibrium on nearby islands

Answer 16

1. 30 bird species
2. 40 years to equilibrium
3. turnover: 1 species per year (was actually >1)

Question 17

Explain the study would insect recolonization in Florida keys

Answer 17

• 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

Question 18

What was the result of the insect study?

Answer 18

• 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

Question 19

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)

Answer 19

B