1. Sexual Selection

2. I.Motivation Sexual Dimorphism is Frequent

6. Figure 11-1

7. Figure 11-3

8. The sexual dimorphism in long-tailed widowbirds Scarlet Tanagers, male, female Wesern Tanagers, male female

9. Human males and females differ in height

10. Why this sexual dimorphism Selection on survivorship and reproduction Ability to obtain mates: Sexual Selection: Different reproductive success due to variation among individuals in success at getting mates If there is heritable variation in a trait that affects to ability to obtain mates, then variants with higher success at obtaining mates will become more common over time

11. II. Limits to reproduction differ between the sexes

12. Guess What? With few exceptions, females invest much more time and energy in the production of young

13. Figure 11-6

14. Asymmetries in sexual reproduction in rough-skinned newts

15. females males

16. Exception to the Rule?” Asymmetries in sexual reproduction in broad-nosed pipefish Male with Kids (in pouch)

17. Males Females

22. Consequences of Asymmetric Limits on Fitness Members of the sex subject to strong sexual selection will be competitive (Male-male competition) Members of the sex subject to weak sexual selection will be choosy (Female Choice) Bateman’s rule, males limited by access to mates, females limited by resources

23. III. Natural Selection Limits Sexual Selection e.g., marine iguanas

24. Larger iguanas expend more energy on metabolism

25. Male marine iguanas in combat

28. Large territorial males

29. Alternative mating strategies in coho salmon

30. IV. Male Access to Females Sperm Competition

31. Sperm competition in damselflies

32. Sperm morphology in rodents All for one and one for All! Sperm Swimming Speeds

33. Infanticide

34. V. Evidence for Sexual Selection on Trait: Female Choice

35. Long tail feathers are a ball-and-chain for male red-collared widowbirds

36. Female red-collared widowbirds prefer long-tailed males

37. VI. Fisher’s Run Away Sexual Selection An example from UMD

38. How runaway selection works in theory

42. VII. Good genes model of sexual selection

44. Are male gray tree frogs that give long calls genetically superior to males that give short calls??

46. Courtship and mating in hangingflies

48. VIII. Origin of Trait Selection Water mite waiting in ambush for a copepod, male has found her

49. A phylogeny of the water mite Neumania papillator and several related species. The boxes above the tips of the branches indicate which species have net-stance and which species have male courtship trembling. A colored box indicates the trait is present; an open box indicates the trait is absent. The two versions of the phylogeny show the two most likely scenarios for the evolution of these two traits. Redrawn from Proctor (1992).

50. Lilies from from SW Aust.

51. IX. Sexual Selection in Plants

53. X. SEXUAL SELECTION IN HUMANS Kipsigis men and women

54. A. Preindustrial Finnish Population B. Pimbwe, a horitcultural society in Tanzania

55. unokais (killers) versus non-unokais among Yanomamö men

56. Figure 11-50

57. Human Stature

58. Taller Polish Men Have More Children:

59. Importance of physical attractiveness in mate choice versus parasite prevalence in 29 human cultures

60. GENETIC DIVERSITY REVEALED IN HUMAN FACES Hanne C. Lie, Gillian Rhodes, and Leigh W. Simmons: Evolution 2008

61. XI. Conclusion Sexual Dimorphism Sexual Selection Males limited by access to mates Females limited by resources Exceptions Universal, aspects found in plants and animals YOU too may be a target for sexual selection Very Kewl