1. Speciation

2. What is a species? A species is—
A group of organisms with similar internal and external structures that can interbreed to produce fully fertile offspring
Species that exist today are essentially changed versions of older species

4. How do species give rise to other different species?
Speciation is a word used to describe the process of changes adding up over time and resulting in a new species
1 species branches into 2 closely related species
Over time they may stay very similar to the ancestral species or to each other, or they may become very different over time

7. What causes branching to occur?
1st Isolation
Two or more parts of a population (species) stop interbreeding- gene flow between them stops forming 2 different gene pools
Types of isolation:
Geographic Isolation
Post-mating Isolation
Behavioral Isolation
Temporal Isolation
Then The Big 3!
1)Natural Selection
2) Genetic Drift
3) Mutations

8. Geographic Isolation
The original population is separated into two or more populations by physical barriers such as canyons, mountains, bodies of water, deserts, or any geographic feature they can’t cross
The Big 3! - Natural selection ,genetic drift and mutations cause different changes to occur in each new population
Since they no longer share genes these changes add up over time until they look and behave so different they no longer breed

10. Geographic
Example:
Pupfish

11. V,W

13. Geographic
Example:
Grand Canyon Squirrels

17. Draw AND explain
Geographic
Isolation in your
own words

18. Post Mating Isolation 1= Mate but can’t produce any offspring OR
2= Mate and produce offspring but the offspring is infertile (can’t have babies)

20. Behavioral Example
In this isolation two populations could breed but have different ways of attracting their mates

23. Temporal Example
The populations reproduce at different times
Example:

25. Speciation Big Ideas!!!
Isolation + The Big 3– 1) Natural Selection ) Genetic Drift ) Mutations