Polygamy - quite wide concept. It is contrast of a monogamy. There is this term from the Greek words πολύς — "numerous", γάμος — "marriage" also is transferred literally as "polygamy".
Polygamy in the nature
In the nature there are monogamous and polygamous animal species, it concerns mammals, reptiles, birds, fishes and insects. Monogamous animals choose to themselves couple once and for the rest of life or before death of one of partners, and polygamous can change few times in several years, each marriage season or within one marriage season.
There are types in which males copulate with several females and vice versa. Males and females of some types change the partner each new marriage season, and representatives of other types copulate during a reproduction season more than with one individual of an opposite sex. Such behavior of males is called a poliginiya, and females - a poliandriya. Many animal species (mainly small) do not form couples at all and have chaotic communications, this phenomenon is called promiscuity.
In botany the polygamy means presence at a plant of a certain species of both same-sex, and oboyepoly flowers. At the same time they can be on one plant or on different plants of one look. In the first case the plant can have oboyepoly and men's, oboyepoly and pistillate flowers, or all at once. Men's, pistillate and oboyepoly flowers are in the second case on different plants of one look.
Situation in human society
If each species of animals has a certain marriage system as specific sign, then at people a variety of types of behavior is observed. Throughout history and in the different countries, and within one country there are different forms of relationship - monogamous and polygamous. The polygamy means that marriage consists with two or more partners. In a number of the countries it is resolved officially at observance of certain conditions. So, in the Islamic countries the man can have several wives if he is able to support all of them and to be responsible for them. It is authorized to women to have several husbands in Tibet, in certain regions of India, Pakistan and Bangladesh. However there are no people or the country for which all citizens the polygamy would be the rule. There are several forms of polygamy. The polygamy means that at one husband it is several wives and all spouses live in one house. If at the woman at the same time two and more husbands, it are called a poliandriya. The concept group marriage characterizes family of several husbands and wives. In the broadest sense polygamous call people who are inclined to have relations with several representatives of an opposite sex at the same time and are not capable to remain long faithful to one partner. Sometimes it is possible to hear opinion that in women the nature put a monogamy, and in men polygamy, however that does not have no proofs. In recent years researchers express opinion that the monogamy or polygamy can be caused by presence at the person of any given gene and to create the harmonious union, it is necessary to look for the partner or the partner with a similar gene.