1. How Populations Evolve

3. Voyage of the Beagle

4. Jean Baptiste Lamarck

5. Charles Lyell

7. Artificial Selection

9. Natural Selection Darwin saw natural selection as the basic mechanism of evolution – As a result, the proportion of individuals with favorable characteristics increases – Allele frequencies (and therefore phenotypes within a population) gradually change over time

10. These five canine species evolved from a common ancestor through natural selection Figure 13.4C African wild dog CoyoteFoxWolfJackal Thousands to millions of years of natural selection Ancestral canine

11. The evolution of insecticide resistance is an example of natural selection in action Figure 13.5B Chromosome with gene conferring resistance to insecticide Additional applications of the same insecticide will be less effective, and the frequency of resistant insects in the population will grow Survivor Insecticide application

12. Fossils provide strong support for evolution

13. Ammonite casts; Fossilized leaf

15. Other evidence for evolution comes from Comparative anatomy (e.g. homologous structures)

16. Biogeography

17. Comparative Embryology

19. Molecular biology

20. Examples of natural selection – camouflage adaptations in different environments

21. Population Genetics and Modern Evolutionary Synthesis Theory Population genetics Studies how populations change genetically over time The modern evolutionary synthesis theory Connects Mendelian Inheritance, Darwin’s theory with population genetics Gene pool Is the total collection of genes in a population at any one time Microevolution Is a change in the relative frequencies of alleles in a given gene pool

22. Gene pool in a nonevolving population remains constant over generations.

25. Hardy-Weinberg Principle States that allele and genotype frequency in a population remain constant (equilibrium) – from generation to generation unless an outside influence disturbs the balance.

26. Hardy-Weinberg Principle Must satisfy five conditions The population is very large The population is isolated Mutations do not alter the gene pool Mating is random All individuals are equal in reproductive success

27. Hardy-Weinberg Equation p 2 + 2pq + q 2 = 1 p + q = 1 Where p is frequency of the dominant allele; q is the frequency of the recessive allele p 2 is the frequency of the homozygous dominant genotype 2pq is the frequency of the heterozygous genotype q 2 is the frequency of the homozygous recessive genotype

28. The Hardy-Weinberg equation is useful in public health science Public health scientists use the Hardy- Weinberg equation To estimate frequencies of disease- causing alleles in the human population

29. Other contributors to evolution include Genetic Drift – change in the relative frequency of an allele Bottleneck effect Founder effect Gene Flow – movement of alleles from one population to another Emigration/immigration

30. Bottleneck Effect

31. Founder Effect Loss of genetic variability when a new population is established by a very small number of individuals from a larger population.

32. Founder Effect Polydactylism Island of Krakotoa, 1883

33. Variation is extensive in most populations Many populations exhibit polymorphism Different forms of phenotypic characteristics Functions to retain variety of morphs in a population living in a varied environment VARIATION AND NATURAL SELECTION

34. Polymorphism

35. Populations may also exhibit geographic variation Variation of an inherited characteristic along a geographic continuum

36. Sexual recombination

37. Evolutionary Fitness?

38. Natural selection can alter variation in a population in three ways Stabilizing selection Directional selection Disruptive selection

39. Modes of Selection

40. Sexual selection may produce sexual dimorphism Sexual selection leads to the evolution of secondary sexual characteristics Which may give individuals an advantage in mating Figure 13.17A Figure 13.17B

41. Processes and Mechanisms of Evolution Adaptation Genetic drift Gene flow Mutations Natural selection Speciation