Sexual Selection

• Sexual selection


  an evolutionary explanation of partner preference, attribute or behaviours that increase reproductive success are passed on.
• Anisogamy


  Differences between male and female sex cells:

  • size
  • mobility
  • quantity
  • time produced for
  • energy expenditure

  Fertile females are a rare 'resource' meaning there are different mating strategies.
• Inter-sexual selection


  Preferred strategy for females, where they choose quality over quantity. This is because they have fewer gametes and make a greater investment of time, commitment and resources before and after birth. The consequences for poor choice are more serious for women meaning they are more choosy with their potential partners, they want fit males who can pass good genes onto offspring.
• Intra-sexual selection 


  Preferred strategy for males, where they choose quantity over quality. This is because they want as many fertile females to pass down their genes. Often results in competition for females with the winner being able to reproduce.
• Body Shapes


  D. Singh studied body types and said that any size is attractive so long as the ratio one to the other is 0.7, as it signals a woman is fertile.
• Eval : Strength


  Buss conducted surveys in 33 countries with over 10,000 adults asking questions relating to age and attributes important for partner preference. He found women had higher value on resource related characteristics whereas men valued reproductive capacity and looks.
• Eval : Strength


  Clark and Hatfield asked female and male university students to approach same sex students on a uni campus and ask if they will sleep with them. They found that 75% of males said yes immediately, whereas 0% of females said yes.
• Eval : Weakness


  Penton-Voak et al found that women's mate preferences change with the menstrual cycle, as their choose strong masculinity in their fertile period and feminised features as long-term partners. This suggests that mate choice may be more complex and down to multiple factors, instead of just genetic fitness.