How did family evolve?

Answer 1

A family is a group of related people.

A nuclear family is a husband and wife, living with their non-adult children.

An extended family is several related nuclear families, including three or more generations.

The extended family never "evolved" it always existed from the time of prehistoric hunter-gatherers.

Answer 2

Perhaps the question is better answered as 'why did family evolve?'. All creatures have their own ways of ensuring their species thrive and survive; family (communal) life is one of those ways. In simplified terms, animals live like this:

Solitary animals:

Some creatures are solitary; that is, they meet, mate, and separate. One - usually the female - nurtures the young until they become independent and leave that parent, or the young imediately go their own way, independent from the start.

Creatures who live this way include many reptiles and insects, animals which simply lay their eggs and leave the young to hatch; the young simply go straight out into the world to begin the cycle again. Rarely, birds come into this category; the majority of cuckoo species, for example, lay their eggs in the nest of a host bird of another species and never see their own young. Most cuckoos, though, have a single mate whom they stay with: they are monogamous.

Pairing animals:

Others meet, mate, and remain together as the young arrive and grow. They continue together, producing and - often jointly - nurturing the young.

Usually, this family is part of a wider group, although sometimes that wider group is a community in which other members of the species living nearby play little or no part in each pair's family life. When the young reach sufficient maturity they leave to find their own mate and territory. Frequently, the mated pairs are monogamous; many bird species live in this way.

Communal animals:

In communal animals the family is part of a wider community which closely involves itself in nurturing its young, collecting food, sharing, and sometimes constructing, accommodation, and generally cooperating in order to ensure safer and more comfortable lives.

This last group is what we usually think of as a family. It's one of the ways an entire species invests in its continued growth and survival; such species evolve a political hierarchy - a status pyramid - in order to ensure decisions by community leaders - usually overseen by a single leader, with a deputy who will later succeed them - are as close as possible to optimum for the mated pairs, the young, and the wider members of the community. Each family group within the wider community evolves its own political pyramid, with one of each family mainly responsible for family decisions, but still deferring to the leader of their particular extended family and, ultimately, to the community leader when matters arise which affect large parts of, or the entire, group.

This communal life - that of the extended family - is a common way of life among birds and mammals.

The word, 'family', is from the Latin term 'familia', meaning household members, including relatives and servants, from 'famulus', servant, of Indo-European roots.