1. Speciation

2. Species
An organism that can mate with another and produce fertile offspring

3. Speciation Isolating Mechanisms Different gene pools
2 species cannot interbreed to produce fertile offspring  Reproductively Isolated

4. Behavioral Isolation
Differences in courtship rituals or other types of behavior
Songs of birds

5. Geographic Isolation
2 populations separated by geographic barriers (rivers, mountains, bodies of water)
Abert Squirrel vs. Kaibab Squirrel

6. Temporal Isolation
Species reproduce at different times

7. Speciation Northern Arctic Fox Spreads northward and
Adapted to heat
through lightweight
fur and long ears,
legs, and nose, which
give off more heat.
Adapted to cold
through heavier
fur, short ears,
short legs, short
nose. White fur
matches snow
for camouflage.
Gray Fox
Arctic Fox
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Spreads
northward
and
southward
separates
Southern
population
Northern
Early fox

8. Speciation Two species arise from one Allopatric Sympatric
Requires Reproductive isolation
Geographic: Physically separated
Temporal: Mate at different times
Behavioral: Bird calls / mating rituals
Anatomical: Picture a mouse and an elephant hooking up
Genetic Inviability: Mules
Allopatric
Speciation that occurs when 2 or more populations of a species are geographically isolated from one another
The allele frequencies in these populations change
Members become so different that that can no no longer interbreed
Sympatric
Populations evolve with overlapping ranges
Behavioral barrier or hybridization or polyploidy

9. COEVOLUTION: Interaction Biodiversity
Species so tightly connected, that the evolutionary history of one affects the other and vice versa.

10. Adaptive Radiation
Single species or small group of species evolves into several different forms
Darwin’s Finches
Reptiles & Dinosaurs

11. How Long does Evolution take?
Gradualism
Slow changes over time
Punctuated Equilibrium
Long, stable periods followed by short periods of quick changes

12. Gradualism