Explaining the co-operation in animals.
Inclusive fitness – When the group (That functions as one.) and only the group and everyone in it is important.
Individuals, and groups of individuals, frequently attempt to control the reproductive activities of other individuals with whom they share genes in common. Such actions might clearly affect the inclusive fitness of “the influencers.”
In many species, this control often takes the form of the reservation (or attempted reservation) of breeding rights for certain members of a group (e.g. the alpha pairs in wolves and meerkats, or the queen in some of the social insects such as group-living ants). The ultimate aim, however, is the regulation of which genes get passed on to the following generation and via whom.
It is not difficult to imagine that social behaviors related to the control of reproduction might evolve in many species since inclusive fitness is really all about reproduction. Just as there is likely an “altruism gene” (or complex of genes), there is probably a complex of genes affecting behaviors related to the social control of reproduction.
In Western society this social control of reproduction has manifested itself in the recent past, for example, in the desire of parents to give formal approval of their children’s (especially daughters’) choice of spouse.
In other societies they go as far as arranged marriages. In some societies the bride is purchased.
In societies with relatively higher levels of genetic relatedness between family members, social control of reproduction has manifested itself in restrictions of interaction between unrelated men and women.
The Chinese practice of foot binding may also have been a way to limit the reproductive options of members of that society.
FBD (father’s brother’s daughter) are even more genetically related than those which simply practice general cousin-marriage since all of the males in the FBD lineages will share the same Y-chromosome.