Natural Selection

Question 1

Allopatric speciation

Answer 1

Geographical isolation
Creates separate gene pools with no interbreeding
Variation due to mutation
Different selection pressures
Selection for different advantageous alleles
Differential reproductive success
Leads to change in allele frequency
Occurs over a long period of time
Populations no longer able to interbreed.

Question 2

Sympatric speciation

Answer 2

Occurs in the same population
Mutations causes variation
Reproductive separation with no gene flow
Different alleles selected
Change in allele frequency
Disruption selection
Eventually different species which cannot interbreed.