1. The Process of Speciation
Chapter 16.3:
The Process of Speciation

2. Speciation The formation of new species
Because a population of individuals has a shared gene pool, a genetic change that occurs in one individual can spread through the population as that individual and its offspring reproduce

3. Reproductive Isolation
As new species evolve, populations become reproductively isolated from each other
Reproductive isolation occurs when members of two populations cannot interbreed and produce fertile offspring
Can develop by behavioral isolation, temporal isolation, and temporal isolation

4. Behavioral Isolation
Occurs when two populations are capable of interbreeding but have differences in courtship rituals or other reproductive strategies that involve behavior

5. Geographic Isolation
Occurs when two populations are separated by geographic barriers such as rivers, mountains, or bodies of water
Temporary geographic features does not guarantee isolation
Geographic features may isolate some species but not others

6. Temporal Isolation
Occurs when two or more species reproduce at different times

7. Darwin’s Finches
Darwin hypothesized that the finches he found on the Galapagos Islands descended from a common ancestor
He proposed that natural selection shaped the beaks of different bird populations as they adapted to eat different foods

8. Darwin’s Hypothesis Proven
Speciation in the Galapagos finches occurred by founding of a new population, geographic isolation, changes in the new population’s gene pool, reproductive isolation, and ecological competition