1. THE PROCESS OF SPECIATION

2. What is a Species? Species - a group of organisms capable of interbreeding and producing fertile offspring.

3. Speciation Speciation is the formation of a new species.

4. Isolating Mechanisms Reproductive isolation occurs when a population splits into two groups and the two populations no longer interbreed. When populations become reproductively isolated, they can evolve into two separate species.

5. Behavioral Isolation Behavioral isolation occurs when two populations that are capable of interbreeding develop differences in courtship rituals or other behaviors http://www.youtube.com/watch?v=nS1tEnfkk6M&safety_mode=true&persist_safety_mode=1&safe=active

6. Geographic Isolation Geographic isolation occurs when two populations are separated by geographic barriers such as rivers, mountains, or bodies of water.

7. Temporal Isolation Temporal isolation happens when two or more species reproduce at different times.

8. What separates one species from another? A)Ability to live in the same habitat A)Ability to interbreed and produce fertile offspring B)Ability to be fertile at different times of the year C)Ability to mate and interbreed

9. What type of isolation is caused by a river cutting through a valley and separating two groups of a species? A)Behavioral B)Geographic C)Temporal

10. What type of isolation is caused by three different flowers blooming at different times of the year? A)Behavioral B)Geographic C)Temporal

11. Speciation in Darwin’s Finches Speciation in Galápagos finches occurred by: founding of a new population geographic isolation changes in the new population’s gene pool behavioral isolation ecological competition.

12. Founders Arrive Many years ago, a few finches from South America—species M—arrived on one of the Galápagos islands, as shown in the figure.

13. Geographic Isolation Because of the Founder Effect the traits of these birds differed from the original population. Allele frequencies – how often different traits show up in the population.

14. Changes in Gene Pool Over time, populations on each island adapted to local environments. Natural selection could have caused two distinct populations to evolve (A and B), each characterized by a new phenotype (observable trait).

15. Behavioral Isolation Depending on local environments, different birds behaved differently further isolating them.

16. Competition and Continued Evolution Birds that are most different from each other have the highest fitness. More specialized birds have less competition for food. Over time, species evolve in a way that increases the differences between them, and new species may evolve (C, D, and E).