Speciation

The formation of a new species

Speciation- occurs in isolated populations

Geographic isolation leads to reproductive isolation

Once the population is geographically isolated, they adapt to their unique environment.

If they can no longer breed with the original larger population they are considered a separate species.

Ex: Galapagos Finches1. Finches on the mainland migrate along the

coast2. Blown off course, they landed on the

Galapagos Islands.3. With lots of food an no predators their

population increased.4. They spread to the other islands.

5. They adapted to the conditions on the separate islands. (mutations caused different bills)

6. The Finches became separate species once they no longer reproduced with those whose bill was different.

Ex: Death Valley Fish1. Once a large lake filled the valley, with one

large fish population.

2. As the climate changed the lake dried up.

3. The fish became isolated in separate ponds and adapted to local conditions.

4. They are now separate species.

Devil’s Hole Pupfish

Salt Creek Pupfish

Divergent evolution:One species becomes many

Ex: Darwin’s Finches

also called: adaptive radiation

Convergent evolution:unrelated species become similar because they adapt to the same habitat

placental mammal vs marsupial white tail deer kangaroo