Sympatric Speciation, Galapagos Finches & Cichlid Fish

Question 1

What is sympatric speciation?

Answer 1

• when a new species arises in the same area as the ancestral species without any geographic isolation

Question 2

How did the different species of Galapagos finches arise?

Answer 2

After arrival on an island, the finches remained permanently isolated from their point of origin and were free to evolve because there was:
- an absence of pre-existing predators
- no competition from other land birds as there were none there
- a variety of empty ecological niches, each with its own type of food

Question 3

What are the stages in the speciation process (in terms of the Galapagos finches)?

Answer 3

1. division of habitat
2. division of food resources by trophic (feeding) specialisation

Question 4

How did the different species of cichlid fish in Lake Malawi arise?

Answer 4

• the lakes provided a variety of empty ecological niches, each with its own type of food
• with no other fish there was no competition
• there was an absence of pre-existing predators

Question 5

What are the stages in the speciation process of the cichlid fish in Lake Malawi?

Answer 5

1. division of habitat
2. division of food resources
3. division by sexual selection