Anisogamy

The term anisogamy describes a form of sexual reproduction in which the gametes, or sex cells, produced by the two sexes differ in dimension, as males produce smaller gametes (sperm) and females produce larger gametes (egg cells). Researchers believe that anisogamy evolved from isogamy (where produced sex cells are equal in size) in order to ensure the reproductive success of the species, given that all animals capable of sexually reproducing are anisogamous. Males have developed the capacity to produce large numbers of small gametes, which gives them more reproductive advantages in comparison to females since they produce a lower number of sex cells and expend more energy during this process.