PREFACE<br >This book is based on a series of programmes made*tbr BBC Television. It and they are<br >sequels to an earlier series and book entitled Life on Earth. That project attempted to<br >describe the way in which animals and plants developed on this planet over the past<br >three thousand million years and traced the rise of different groups of animals which<br >culminated in the expansion of the mammals and ultimately the appearance of man.<br > This new book surveys the situation as it is today. It examines the manner in which<br >the survivors of ancient groups as well as the representatives of newly-evolved ones<br >have together colonised and adapted to the great variety of environments that exist on<br >earth. Here and there， the two narratives may overlap slightly， but the variety of animals<br >and plants is so immense that I have been able， in most instances， to illustrate such<br >episodes with species other than those described in the earlier book.<br > I have retained the same style as before， avoiding as far as possible technical scientific<br >terms and not encumbering the text with Latin names. However， the index has been<br >compiled to serve as a glossary in which each organism is given not only a page reference<br >but also its scientific name， so a reader who wishes to know precisely what family， genus<br >or species is being referred to can discover by looking it up in the index.<br > The book was written at the same time as the programmes were being filmed. The<br >one is not， therefore， the direct descendant of the other. Rather the two are cousins，<br >both descended from the same body of research and years of travel. They therefbre<br >have the sort of differences and likenesses that you might expect from such a relation-<br >ship. I hope the one may enhance the other.<br >