1. Population Genetics & Speciation

2. Populations Adapt – Individuals Can’t (They acclimatize)
Fitness = ability to make a hereditary contribution to the next generation
Populations Adapt – Individuals Can’t (They acclimatize)

3. Q: How do we see evolution?
A: In populations Natural Selection acts on populations by changing the composition of the gene pool.

4. Gene Pool
Gene pool refers to the total number of genes of every individual in a population. A large gene pool indicates high genetic diversity, increased chances of biological fitness, and survival.

5. Population Genetics
Bell Curve – Ding! You’re most likely…just average!

6. Types of Selection – 3 Types Directional Stabilizing Disruptive

7. Directional Selection

8. Directional Selection

9. Directional Selection

10. Directional Selection

11. Stabilizing Selection

12. Stabilizing Selection

13. Stabilizing Selection
NN nn
Nn?

15. Disruptive Selection

16. Disruptive Selection

17. Disruptive Selection

18. Disruptive Selection

19. Types of Selection

20. Can selection eventually lead to new species?

21. What is a species?
Morphological Species Concept: Focuses on morphology.

23. What is a species?
Biological Species Concept – organisms that can successfully interbreed but can’t breed with other organisms

26. Species - Best Definition:
A single kind of organism. Members are morphologically similar to each other and can interbreed to produce fully fertile offspring.

27. Speciation
The process of species formation

28. Speciation – 2 steps
Involves Isolation (Reproductive and/or Geographic)
Then adaptation (Selection)

29. (Adaptation)
(Isolation)

31. Isolation
Geographic or Reproductive

32. Reproductive Isolation
Prezygotic
- barrier to creation of zygote
Postzygotic
– zygote formed, barrier/limitation related to development/reproduction/fitness

33. Reproductive Isolation – reduced fitness of hybrids
Prezygotic or Postzygotic?
Hybrids…
Horse = 64 Donkey = 62 Mule = 63
Liger and Tiglon

36. Reproductive Isolation – Temporal Isolation Prezygotic or Postzygotic?

37. Behavioral Isolation Prezygotic or Postzygotic?

38. Prezygotic or Postzygotic?

39. Geographic Isolation

43. Allopatric Speciation
“different homelands”
Geographic Isolation

44. Allopatric Speciation
“different homelands”
Geographic Isolation

46. Sympatric Speciation
“same homeland”
Reproductive Isolation

47. Sympatric Speciation
“same homeland”
Reproductive Isolation