Sexual selection

• Who came up with sexual selection 


  Darwin
• sexual selection general idea


  those with the best genes are sought out to pass genes onto younger generations
• anisogamy


  difference in M/F sex cells (gametes)

  M = sperm (small, numerous)

  F = egg (large, singular)
• Consequence of anisogamy


  Fertile females are rare but fertile males are numerous
• inter sexual selection


  female. choosy because consequences greater, males compete female chooses genetically fit male
• intra sexual selection


  males. competition for female, winner reproduces and passes on characteristics to offspring
• runaway process in sexual selection 


  e.g height is attractive > over generations male height increases as females are choosing tall men who birth tall sons or daughters who want tall males. continues cycle
• Strength of anisogamy in sexual selection 


  Support evidence, Buss 10000 adults 33 countries survey ask about important things for partner. Females valued recourses like money, males valued reproduction like youth.
• strength of inter selection


  evidence to support female choosiness. clark + hatfield had students ask strangers for sex. 0% women agreed but 75% men agreed. shows females choosy but men quantity
• weakness of sexual selection 


  research ignores social influences, modern day influences preferences e.g women can work so arent dependent on male resources. preferences outcome of both evolutionary and social influences