1. Evolution of Populations Marie Černá

2. Microevolution Genetic drift in small population Gene flow by migration Mutation Nonrandom mating Natural selection

3. Genetic Drift

4. Genetic Drift - small populations

5. Genetic Drift - large populations

6. Genetic Drift - Bottle neck effect

7. northern elephant seals of the coast of Mexico During the 1890’s, their population was reduced due to hunting to about 20 individuals. (It is also likely that one male would have fathered the offspring of the entire group.)

8. Genetic Drift - Founder principle Drosophila subobscura (fruit fly) European → American

9. Genetic Drift - Founder principle

10. Gene flow - migration

11. Mutation

12. Nonrandom mating inbreeding assortative mating

13. Natural selection the differential ability to survive and produce viable, fertile offspring is likely to adapt a population to its environment (accumulates and maintains favorable genotypes)

14. Genetic variation: the substrate for natural selection within populations (polymorphism) between populations (geographical variation)

15. Polymorphism

16. Geographic variation

17. Geographic variation - Cline

18. Sources of Genetic variation Mutation (affection of function) Sexual recombination

19. Crossing over in meiosis

20. Independent assortment

21. Preservation of Genetic variation Diploidy (heterozygote protection) Balanced polymorphism

22. Heterozygote advantage

23. Frequency-dependent selection

24. Modes of natural selection

25. Directional selection is most common - during periods of environmental change - when members of a population migrate to some new habitat with different environmental conditions

26. Directional selection peccaries Desert cactus population

27. Diversifying selection

28. a species of finch lives in Cameroon, West Africa small-billed birds (soft seeds) large-billed birds (hard seeds)

29. Stabilizing selection This mode of selection reduces variation and maintains the status quo for a particular phenotypic character. It keeps the majority of human birth weights In the 3 – 4 kg range. For babies much smaller or larger than this, infant mortality is greater.

30. Stabilizing selection Desert cactus population

31. Literature Biology, eighth edition, Campbell, Reece Unit four: Mechanisms of Evolution Chapter 23: The Evolution of Populations Pages 468 – 486