sexual selection and human reproductive system Flashcards
Sexual selection
An evolutionary explanation of partner preferences and refers to the attributes or behaviours that increase reproductive success,
are passed on to offspring
Human reproductive behaviour
Refers to any behaviours which relate to opportunities to reproduce and thereby increase the survival chances of our genes
Anisogamy
Refers to the differences between male and female gametes.(sex cells)
Male sperm:
produced faster and in vast numbers
Female egg:
produced at intervals and limited in number
Consequences of anisogamy
There is no shortage in fertile males but a fertile women is a rare resource. Give rise to two different mating strategies:
Inter-sexual selection
Intra sexual selection
Intersexual selection
Strategy females use to select males. Quality over quantity
Trivers (1972) (intersexual selection)
Female makes greater investment of time, commitment and other resources before and after birth of her offspring. Female select genetically fit partner who is able and willing to provide resources
Runaway process (part of intersexual selection)
Fisher argues that a female mates with a male who has a desirable characteristic and this sexy trait is inherited by her son. This increases the likelihood that a female will mate with her offspring
Intra sexual selection
occurs within each sex and is preferred by the males (quantity over quality). Refers to the competition between males to be able to mate with a female. The winner of this competition reproduces and gets to pass on his genes to his offspring. This has given rise to sexual dimorphism.
Sexual dimorphism
Obvious differences between males and females. For example between males size matters. larger males have an advantage and therefore more likely to mate. females don’t do this because they do not favour larger females.
