relationships

• Sexual selection

  Darwin's theory which suggests that some characteristics evolve because they provide a reproductive advantage
• Sexual selection

  • They are either attractive to potential mates or they provide an advantage over competitors
• Anisogamy


  Intra-sexual selection - where male gametes are created in larger quantities. So their best strategy is to mate with as many females as they can which results in the maximum number of offsprings
• Intra-sexual selection


  Quantity over quality. Males compete for fertile women meaning they have evolutionary preference for those who show features of fertility
• Inter-sexual selection


  Female gametes are produced at intervals for a limited time during fertile years. Women will be more picky with who they mate with. Females invest more time, commitment and resources before, during and after birth. They prefer a strategy of quality over quantity.
• Fisher's sexy son hypothesis


  Females' preference determines which feature will be passed on to the offspring e.g. tallness. The preference of one sex determines the areas in which the other sex must compete with.
• Research support for sexual selection

  • Buss - females place greater importance on resource related characteristics, males more interested in looks. Shows support for partner preference derived from sexual selection, can be applied cross-culturally as it was a survey across 33 different countries.
• Research support for inter-sexual selection

  • Clark and Hatfield - uni campus study asked students to sleep with - no female said yes whereas 75% of males said yes. Shows that females are choosier and have evolved a different strategy to males.
• Sexual selection ignores social/cultural influences. Partner preference has been influenced by social and cultural factors which develop much faster than evolutionary timescale.
• Such as women's role in the workplace means they are less dependent on men as providers. Social change means that women's preferences are no longer source oriented.
• Chang et al - compared partner preference in China over 25 years and found that there has been some change.