Evolutionary Approach

• What is evolution?


  a process of gradual change that takes place over many generations, during which species of animals, plants or insects slowly change some of their physical characteristics
• what is natural selection?

  a mutation in a gene occurs which gives the organism a survival advantage.

  This then means they survive to reproduce, passing on the gene that codes for the survival advantage
• give 2 details about the process of natural selection?

  • gradual
  • takes millions of years
• Define sexual selection?


  the selection of characteristics increasing reproductive success
• Define socio-biological explanation?


  A theory of relationships based on biological determinants
• Give one way in which evolution works to shape human reproductive behaviour?

  that of sexual selection
• Define anisogamy?


  the different between the nature and amount of gametes
• What does anisogamy result in?

  Different mating strategies between males and females
• Describe the male mating approach?


  quantity not quality
• male mating strategy?


  Have sex as much as possible with multiple women to ensure reproduction success
• when are males fertile until?

  90
• what can males do?

  fertilise many females without a huge cost - POLYGAMY
• What can males also do?

  can leave women 'holding the baby' little resource required pre and post having the baby
• female strategy?


  quality over quantity
• what do females produce?

  much fewer eggs

  • 300 mature in a lifetime
• what MUST females do?

  they must therefore be more selective about who they mate with as have to invest lots of resources into the offspring
• female strategy?


  monogamy is the strategy used - choosing ONE MALE FROM THOSE AVAILABLE
• Why is anisogamy important?

  it results in different mating strategies in males and females and thus 2 different types of sexual selection
• Intra-sexual selection?


  Where members of one sex COMPETE WITH EACH OTHER for access to members of the OTHER sex.

  The victors are able to mate & so pass on their genes, the losers do NOT.

  Whatever TRAITS lead to SUCCESS are then PASSED ON to the next generation
• Inter-sexual selection?


  This form of selection involves the preference of one sex for members of the opposite sex who possess certain qualities.

  The preferences of one sex, therefore determine the areas in which the other sex must COMPETE
• Give details about modern day relationships ?

  • Homosexual relationships
  • independent women who are more interested in their career
  • contraception & choosing not to have children