AO1

• Any genes which are advantageous for survival are naturally selected. In addition, any genes that promote successful reproduction are selected, which is called sexual selection.
• Anisogamy is the difference between male and female sex cells. Females produce larger and fewer eggs and will be more selective in choosing mates because they invest more energy in reproduction. Females will look for qualities in a mate that indicate good genes or parental investment. Males who produce smaller and more numerous sperm may compete for access to mates. This all leads to mating strategies: intersexual and intrasexual.
• Female eggs are less plentiful, released in a limited time frame, and require much more energy to produce. Males have sperm cells which can reproduce quickly with little energy and once they start being produced they do not stop until the man dies.
• Inter-sexual selection

  Inter-sexual selection is how the different sexes choose the other (e.g., females select males/males select females).
• Inter-sexual selection

  Females make a greater investment of time and commitment before, during and after birth of offspring. Therefore, they choose a genetically fit partner who is able to provide resources. This is why they tend to seek men who display physical health characteristics and is a high-status individual who controls resources within the social group. Male partners are able to protect, provide and control food and resources. In modern day times, this is more likely to relate to occupation, social class and wealth.
• Fisher's sexy sons hypothesis

  The sexy sons hypothesis says that if females choose physically attractive males, they will tend to get physically attractive sons and thus more physically attractive grandchildren because other choosy females will prefer their attractive sexy sons. (use the example of height.)
• Intra-sexual selection

  Intrasexual selection is the selection of mates within sexes, like how males compete with other males for the prime females.
• Intra-sexual selection

  Males compete for access to females as sperm is plentiful, but female eggs are a limited resource. Males who win pass on their genes to the next generations, so the traits that contribute to their victory are perpetuated like height or cunningness.
• Intra-sexual

  Males value quantity over quality. So anisogamy suggests that males best evolutionary strategy is to have as many partners as possible. Intrasexual selection pressures lead to certain patterns of human reproductive behaviour. These can be physical consequences where males who are bigger win competitions for mates, so size is selected in males. Signs of fertility are selected, for example females with curves. Behavioural consequences where male aggressiveness also helps win competitions.