STEPS OF ALLOPATRIC SPECIATION

Question 1

Step 1

Answer 1

members of a large population occupy an environment. Sharing the same genetic pool and interbreeding freely.

Question 2

Step 2

Answer 2

The population becomes split into 2 completely isolated sub-populations by a geographical barrier, preventing interbreeding and gene exchange

Question 3

Step 3

Answer 3

Mutations occur at random therefore mutations that are different from those that occur within the other sub-population, resulting in new variation within each group = not shared by both groups.

Question 4

Step 4

Answer 4

The selection pressures acting on each sub-population are different depending on local conditions such as climate, predators or diseases. Natural selection affects each sub-group in a different way by favouring those alleles which make the members of that sub-population best at exploiting their environment.

Question 5

Step 5

Answer 5

Over a very, very long period of time stages 3 and 4 cause the two gene pools to become so altered hat the groups become genetically distinct and isolated.

Question 6

Step 6

Answer 6

If the barrier is removed, they are no longer able to interbreed since their chromosomes cannot make matching pairs. Speciation has occurred and 2 separate distinct species have evolved