Bio3520 Chapter 7 Mating Systems
  1. Animal mating systems can be classified into several combinations.
    •           occurs when a male and female pair mate only with one another during a breeding season.
    •             mating systems can be divided into polygynous and polyandrous systems.
    •                 , or promiscuous, mating systems involve multiple males and females.
  2. In primates,               may be a female defense against sperm-borne disease.
  3. The Polygyny            Model (PTM) predicts that females choose mating systems based on available            rather than on males.
  4. Many birds once thought to be             , may exhibit some                promiscuity: individuals form pair bonds but engage in            copulations.
  5. In some species, males compete for access to eggs via        competition, where females store sperm from multiple matings, and sperm from different males compete to fertilizable eggs.
    • In primates, sperm competition may lead to larger         size in males.
    • In some insects, sperm competition leads to last male             and prolonged copulation times.
    • The competition involves a           between speed and longevity in individual sperm, and also plays a role in the diversity of sperm             .
    • Sperm competition may even be correlated with sperm        in humans.