Mating systems refer to the ways in which animals pair up for reproduction. The main types include monogamy, where one male mates with one female, and polygamy, which can be further divided into polygyny (one male with multiple females) and polyandry (one female with multiple males). These systems can influence genetic diversity and social structures within species. Different species adopt various mating systems based on environmental factors and reproductive strategies. For example, in some species, like birds, monogamy may enhance parental care, while in others, like lions, polygyny can increase a male's chances of passing on his genes.