1. Development of New Species by Evolution

2. What is Speciation?
It can occur when members of a population become isolated from each other.
Once two populations are reproductively isolated, they are considered separate species.
Speciation is the evolution of 1+ species from a single ancestor species.

3. Allopatric Speciation (Geographic Isolation)
A physical barrier (continental split, rise in sea level, formation of mountain range, advance of glacier, change in habitat) prevents gene flow between populations of a species

4. Sympatric Speciation
A process through which new species evolve from a single ancestral species while inhabiting the same geographic region.

6. Behavioral Isolation
Two populations are capable of interbreeding, but have differences in courtship rituals or other reproductive strategies.

7. Temporal Isolation
Species reproduce at different times.

8. Speciation in Darwin’s Finches
Speciation in the Galapagos finches occurred by:
Founding of a new population
Geographic isolation
Changes in new population’s gene pool
Reproductive isolation
Ecological competition

9. Evolution does not occur in a set direction
Evolution builds on what already exists, so the more variety there is, the more there can be in the future.
However, evolution does not necessitate long-term progress in a set direction.

10. Rate of Evolution
Gradualism - theory that new species evolve as the genomes of two populations differentiate over time.
Punctuated equilibrium - theory that populations remain genetically stable for long period of time, interrupted by brief periods of genetic change.

11. Mechanisms of Evolution
Divergent Evolution - when isolated populations of a species evolve independently.
Convergent Evolution -occurs when Natural Selection has produced similar adaptations in response to similar environment between different species.

12. Coevolution
Species that interact closely often adapt to one another in a process called coevolution.

13. Adaptive Radiation
Adaptive Radiation is the evolution of many diversely adapted species from one common ancestor.
It usually occurs on an isolated island.
Ex. Darwin’s finches

14. Patterns of Evolution