CH4

Question 1

Ecocline

Answer 1

a gradual, continuous change in the genotype/phenotype composition between two ecosystems or communities of organisms across an environmental gradient.

Question 2

Issues with speciation

Answer 2

1. ecocline - where did the changes in genotype/phenotype take place
2. genetically identifiable ecotype - local conditions

how to know if it is distinct enough to be a new species

3. asexual reproduction/hybridization

Question 3

Reproductive isolation

Answer 3

isolating mechanisms to maintain reproductive isolation among populations

prezygotic = no formation e.g. matinf cues

postzygotic = formation (no reproduction after)

Question 4

Causes of speciation

Answer 4

• allopatric
• parapatric
• sympatric

Question 5

allopatric speciation

Answer 5

single population is subdivided into multiple subpopulations with physical boundaries (mountain river ect)

Question 6

parapatric speciation

Answer 6

population expands into new habitat within range of parent species

e.g have mutations to live in another habitat

Question 7

sympatric speciation

Answer 7

single population forms genetically distinct subpopulation w/ no spatial isolation

• not genetic drift. but natural selection
• assortative mating