Sexual selection

• Sexual selection and human reproductive behaviour:

  natural selection

  • process where inherited characteristics become more or less common as they provide environmental advantages to survival
  • through sexual dimorphism, different characteristics evolve and secondary sexual characteristics are displayed to be selected by mate
  • males - ability to provide and protect, females - display fertility to carry and care for children

  sexual selection

  • display desirable characteristics to increase chance of securing a mate
  • inter-sexual selection
  • intra-sexual selection
• Sexual selection and human reproductive behaviour:

  intersexual selection

  • act of selecting mate
  • one sex evolves with preferences for certain desirable qualities in other sex
  • members of opposite sex possessing these qualities are more likely to mate and pass on genes
  • predominantly women engaging in intersexual as choose quality of of great investment, commitment and resources

  intra-sexual selection

  • same sex compete with on another for opposite sex
  • predominantly men as tend to show their ability of protection and providing through fitness
• sexual selection and human reproductive behaviour:

  woman are biologically motivated to invest in care for offspring so carefully select ideal mate to pass down selfish genes

  • seek signs of provision (money) and less signs of protection (muscles)
  • tend to select older partner
  • so women get a mate who can best provide for her and her offspring to pass selfish genes

  men are biologically motivated to in best in less caring for offspring and more to compete to be selected to pass on genes

  • seek signs of youth and fertility
  • increase their chances of having offspring to pass on selfish genes
• sexual selection and human reproductive behaviour:

  long term courtship

  • advantage to men as they have access to a fertile woman
  • advantage to women as theres increased investment resources by man to her and children, reducing chance of him abandoning her

  mate guarding

  • monitor eachother to let potential partners know they’re taken
  • important as men don’t want to waste their resources on a child that doesn’t have his selfish gene
  • important as women need to ensure make uses all his resources on her and her offspring not others
• sexual selection and human reproductive behaviour:

  one night stand and sneak copulation

  • advantage to men as increases reproductive chance without needing to heavily invest
  • offspring will have man’s selfish gene but another man’s resources to raise child
  • advantage to woman as provide assess to wider gene pool and maximise chance of offspring reaching sexual maturity and pass on selfish genes
  • allows woman to retain long term relationship with resource rich husband but genetically poor mate and have offspring with resource poor but genetically fit male