(i) The Need for Population:
Society is composed of separate organisms without whom no society could exist. Societies of all kinds whether insect, animal, or human, must make provision for fulfilling the three basic needs of their members.
These needs of the organisms are (a) the need for nutrition or nourishment, (b) the need for protection and (c) the need for reproduction. These needs are felt by all the species. A social system has to make provision for the satisfaction of these needs through group interaction of some kind. The very introduction of group co-operation may however create new needs for the maintenance of the social system if not for the individual organisms.
(ii) The Need for Specialisation:
Group co-operation among members presupposes the idea of division of labour and specialisation. The group members must have some mode of dividing work among themselves. The degree of specialisation may differ from society to society. It may be very slight in the case of a herd of cattle or it may be very great as it is in ant community.
(iii) The Need for Solidarity: Societies must guarantee some mode of contact between the members and provide for some motivation for such contact. Added to this, the members must have the spirit of tolerance and must be able to distinguish themselves from other non-members.
The individual members must have some means of identifying themselves with the group. They must have some means of resisting the outsiders and the outside influence. Only then, social solidarity or cohesiveness in the group would be found.
(iv) The Need for Reproduction: The society or the group must be able to perpetuate its structure, and character. There must be provision for the continuity of the social system even beyond the life-span of any one individual or generation. This is possible only when there is provision for the members to reproduce their kind.
It is clear from the above, that any kind of society requires certain conditions for its existence. The members of a group or society may not realise them always and strive for their requirements.
It is not implied here that the members must always realise the societal needs and strive for their fulfillment. What could be stressed here is that societies require certain conditions before they can exist. We are, of course, interested in understanding various kinds of mechanisms that have been evolved to supply these conditions.