" To give an example of the way man operates compared to other animals, consider speciation, which, as we know, tends to occur when a small group of animals gets separated from the rest of the herd by some geological upheaval, population pressure, food shortage or whatever and finds itself in a new environment with maybe something different going on. Take a very simple example; maybe a bunch of animals suddenly finds itself in a place where the weather is rather colder. We know that in a few generations those genes which favour a thicker coat will have come to the fore and we'll come and we'll find that the animals have now got thicker coats. Early man, who's a tool maker, doesn't have to do this: he can inhabit an extraordinarily wide range of habitats on earth, from tundra to the Gobi Desert - he even manages to live in New York for heaven's sake - and the reason is that when he arrives in a new environment he doesn't have to wait for several generations; if he arrives in a colder environment and sees an animal that has those genes which favour a thicker coat, he says 'I'll have it off him!'"

Douglas Adams