lecture 3

Question 1

what are the 4 general modes that selection gradient can occur?

Answer 1

1. stabilizing
2. directional selection
3. disruptive selection
4. frequency dependent selection

Question 2

what is frequency dependent selection?

Answer 2

occurs when the fitness of an individual depends on the relative frequency of other phenotypes in the population

Question 3

what is speciation?

Answer 3

a single species splits or speciates, resulting in two daughter species - the ultimate source of biodiversity

Question 4

what does speciation result in?

Answer 4

cladogenesis or the branching of an evolutionary lineage

Question 5

what are the three types of speciation?

Answer 5

1. allopatric
2. parapatric
3. sympatric

Question 6

what is allopatric speciation?

Answer 6

seperation of populations is large relative to dispersial distances

Question 7

what are traits of allopatric speciation?

Answer 7

-prevents gene flow, populations can evolve independently
- adaptation to different local environments
- reproductive isolation tested if barrier disappears

Question 8

what is parapatric speciation?

Answer 8

occurs when a population expands into a new habitat within the pre-existing range of the parent species

Question 9

what is sympatric speciation?

Answer 9

development of reproductive isolation between 2 segments of a single population that are in continuous contact