Separate space is given in Genesis to the creation of humankind because this is the zenith of God's creation.
On the one hand, animals and insects, fish and birds, in all their almost infinite variety and diversity are wonderfully made but they have only bodies not souls or spirits like human beings. They live by instinct and when they die that is their end (although God will no doubt make more in the new heavens and earth).
On the other hand, there are the angels and other heavenly creatures we have mentioned that are spiritual and do not have bodies and do not marry or reproduce. As we have also mentioned they are not the objects of God's interest in the way that human beings are.
Humankind, unlike animals and angels, are spiritual beings that have bodies with which to express themselves. This is underlined in the creation of Adam who was taken from the ground and then breathed upon by God. They are said to be made in the image of God. It is not entirely clear what that means but they do reflect the image of God in a way that no other creatures do or can.
Like animals but unlike angels, human beings can be male or female and in combination are able to reproduce. The whole way this difference came about in God's providence underlines a distinction so that although men and women are clearly equal, it is required of the woman that she submit to the man and help him, rather than the other way around. The Bible is thoroughly patriarchal and yet often points up women's great qualities and always resists stereotypical downplaying of women (see the end of Job for example). This arrangement reflects equality in the Godhead. Marriage, which unites man and woman points also to the relationship God seeks with his people.
It is clear that from the beginning, humankind was intended to rule over the creation. Work was to be an every day thing with weekly rest. The naming of all the animals was one of the first tasks completed by man, a hint at the sorts of activity people would engage in in the future.
Over the years people have come up with various alternatives to biblical family life - man and woman coming together and having children - but this is the original way intended and, although in certain circumstances singleness is a legitimate option, anything else is most likely to be a perversion of what was originally intended.
