1. Objective: to be able to explain how a species originates
Speciation
Objective: to be able to explain how a species originates

2. Speciation
species- have the ability to interbreed speciation- how species originate reproductive isolation….is isolating mechanisms….is reproductive barriers….is

3. Reproductive barriers
Prezygotic barrier before attempt to breed Postzygotic barrier after attempt to breed

4. Prezygotic
Geographic live in different areas Habitat live in same area but different habitat ex: garter snakes-1 species in water, other on land

5. Prezygotic
Temporal reproduce at different times of year or day ex: flowers that only open in morning, others at night Behavioral have different courtship rituals ex: Birds songs that are species specific

6. Prezygotic
Mechanical physically can’t mate--- ex: plants use different pollinators “puzzle pieces” Gametic sperm can’t fertilize the egg ex: sea urchins release sperm and egg, can only fuse with their species

7. Postzygotic
Reduced hybrid viability die early ex: salamander Reduced hybrid fertility can’t reproduce ex: mule Hybrid breakdown offspring can’t reproduce ex: rice