1. 3 events lead to speciation: separation, adaptation and division.
…is the formation of a new species as a result of gradual changes within a population.
3 events lead to speciation: separation, adaptation and division.

3. 1. Separation Part of a population becomes separated from the rest.
They may be separated by a Geographical isolation like a canyon, river, a mountain range, or being on an island.

4. Other kinds of separation are…
Ecological isolation – Species are in the same area but live in different habitats.
Temporal isolation – Species are in same area but are active at different times of the day or reproduce in different seasons.

6. 2. Adaptation
After the groups are separated, each group continues to be affected by their environment:
Different traits can be favorable or unfavorable in different environments.
Over many generations, different traits may spread through each population.

8. 3. Division
The 2 separated populations can become very different from each other.
With time the members of the 2 populations may be unable to interbreed successfully.

10. Finches of Galapagos Islands

11. Fig. 23.6
Four species of leopard frogs: differ in their mating calls.

12. These squirrels live on opposite sides of the Grand Canyon.

13. The California Grey Fox
The Channel Island Fox
The California Grey Fox