1. Natural Selection Unit
Biology

2. January 29: Lesson Question
How might new species form? What keeps species separate?
On the top of page 80

3. What is a species?

4. Species and Speciation
Let’s watch this short video on speciation.
Specitaion
So what is speciation?

5. Geographic Isolation (allopatric)
A physical barrier separates a population into two (or more groups)

6. Speciation
What keeps similar species from breeding and becoming one species?

7. Ecological Isolation
Species occur in same region but rarely encounter each other.
Eastern Blue Bird
Mountain Blue Bird

8. Temporal Isolation
Species that breed during different times of the day, different seasons or different years cannot reproduce.
Western Spotted skunk (winter)
Eastern Spotted skunk (summer)

9. Behavioral Isolation
Mating behaviors are different between similar species.
Birds of Paradise
Blue Footed Booby

10. Mechanical Isolation
For many insects, male and female reproductive organs of closely related species do not fit together.
Damsel fly penises