1. Selection causes Microevolution
• Frequency of alleles (versions of a gene) changes in a population

2. Selection creates Adaptations
Traits common to all members of a population that confer greater success
protective coloration
mimicry
camouflage

3. Selection can lead to Macroevolution
Change on a grand scale
macro
• Become more different over time
• Different enough that populations no longer interbreed
micro

4. = different species

5. From Microevolution to Macroevolution Geographic Isolation
Ensatina salamanders
Inhabit the CA coast, and Sierra foothills, but not the hot , dry Central Valley

6. Geographic isolation causes Reproductive isolation
Do not interbreed
Functionally separate species
Interbreed

7. Organisms that interbreed, producing viable, fertile, offspring
Species?
A mule is neither horse nor donkey – it’s a hybrid of the two
The evolution of a species is called speciation

8. Geographic isolation causes Reproductive isolation

9. Geographic isolation causes Reproductive isolation
Sciurus aberti kaibabensis
North rim
Sciurus aberti aberti
South rim
The Kaibab squirrel (Sciurus aberti kaibabensis, left) became geographically isolated from the common ancestor with its closest relative, the Abert squirrel (Sciurus aberti aberti, right) in the North Rim of the Grand Canyon about 10,000 years ago. Since then, several distinguishing features, such as the black belly and forelimbs have gradually evolved.
Angel Island Lizard too
Sub-species: different, but not yet different enough

10. Other factors also cause Reproductive isolation
Sexual selection

11. Other factors also cause reproductive isolation
• Behavior
• Timing
Lay eggs later, in ripe fruit
Lay eggs in green (early) fruit
Mature at different times, reproductively isolated

12. Once isolated, the groups become less and less alike
via selection, but also via random events
random mutation creates green phenotype
Little or no interbreeding