1. 1 1

2.  We can’t define a species by looks alone! If we defined a species as looking similar, these would ALL be two separate species! 2

3. WWWWe can’t define a species by just producing offspring, either! Cannot Reproduce (sterile) “Beefalo” Mule Liger The offspring have to be fertile or it doesn’t count!! 3

4. 4  A species is:  A group of interbreeding populations  Reproductively isolated isolated (kept apart) from other such groups  Organisms must be able to mate and produce fertile offspring  (This is why mules, ligers, and beefalo aren’t new species! No fertile offspring!)

5.  When you can mate and produce fertile offspring offspring, you are in the same gene pool! Because they can mate and produce a fertile puppy, the Beagle and Pug share a gene pool! 5

6. 6 6 RRRReproductive isolation : when members of two populations cannot mate and produce fertile offspring IIsolation 1. Behavioral 2. Geographic 3. Temporal

7. 7 7  Two species could interbreed but have different courtship rituals  Example: Different bird songs Western Meadowlark Eastern Meadowlark Sounds similar, but different enough to keep them separate

8. 8 8  Rivers, mountains, etc… keep populations apart  Separates into two separate gene pools  Many “abiotic” factors  Abiotic = not living

9. 9 Alpheidae (Snapping Shrimp) around Panama Panama Canal = closest relative What does this mean?What does this mean? Isthmus of Panama formed ~3MYAIsthmus of Panama formed ~3MYA 7 Species of shrimp split into 14 species!7 Species of shrimp split into 14 species! Gene pools have been separated!!

10. 10

11. 11  Species reproduce at different times  Not seen in humans, more in other species  Some animals have periods where they are in “heat”  Animals that reproduce at different times of the year might as well be separated by a geographic barrier

12. 12  Collected from what islands?  Galapagos islands  Why are they special?  Darwin thought they were different different types of birds  Blackbirds, grossbeaks, finches, etc…  ALL finches  13 new species, never seen before 12

13. 13 1. Founders arrive  Birds blown hundreds of miles off of the mainland  Survive & reproduce on island 13

14. 14 2. Islands separate populations  Finches do not like to travel over open water  Geographic (“abiotic”) isolation  No longer can breed with each other 14

15. 15 Lonesome George 15

16. 16 3. Changes in gene pool  Populations adapted to local environment  Different plants on each island means different food for birds  Large seeds require large beaks to crack them open  Small beaks better at opening small seeds 16

17. 17 4. Reproductive isolation  If birds were somehow able to come in contact with each other again, they would be too alien now  Finches are attracted to birds with the same size beak  They are now separate species 17

18. 18  Process of isolation, genetic change, and reproductive isolation has repeated itself many times  13 species of finch found nowhere else on planet 18

19. 19

20. 20 1. Founders arrive 2. Separation  (Geographic, behavioral, temporal) 3. Changes in gene pool 4. Reproductive Isolation 20