This, at least, is the theory of a geology professor from Massachusetts, Mark Mcmenamin, who has just presented a paper on the subject to a meeting of the Geological Society of America in Salt Lake City. Professor McMenamin bases his conclusions on studies of some very peculiar fossils called Ediacarans (named after the Ediacara Hills in South Australia where they were first discovered in the 1940s).
Ediacarans, who seemed to predominate on earth before the evolutionary explosion of the early Cambrian period, were no slouches themselves when it came to development. They took a huge variety of forms, with two basic characteristics in common. First, they all seem to have been soft and bouncy; the second shared feature is that they all resembled modern day upholstered furnishings, or household appliances. Ernietta, for instance, was the same shape as a coffee mug, while others took the form of quilts, mattresses and lampshades.
Not surprisingly, according to McMenamin, these animals were a pacific bunch, lolling around in warm sludge most of the day, lazily allowing nourishment (in the form of photosynthetic algae) to penetrate their bodies - if the algae felt like it. The professor describes this state as being a "Garden of Ediacara".
So what happened? Well, one of our forebears (a very precocious early Trilobyte perhaps) developed the two things that made it a dangerous predator: sense organs which allowed it to locate prey, and - that other big plus in the predatory world - mouth parts, to bite its prey when it had found it.
The one development without the other would have been no threat. But put together they spelled adieu to the Ediacarans. One by one the quilts, mugs and mattresses were hoovered up by our great grandpas and mas. Within the space of an evolutionary tea-break, they disappeared completely from sight, until rediscovered fifty years ago. Our ancestors then started in on each other.
Everything goes somewhere. One wonders what aspects of our deep psyches are affected by our terrible and exploitative treatment of our parallel life form. It is possible that much of our inner feelings of guilt and responsibility originate in the day that one trilobyte turned to one millipede and said, "All gone!" Perhaps it might help us to come to terms with our guilt, were we to apologise to Ediacarans for activities in the Cambrian era.
Other questions are raised too. In recent years some historians (notably Niall Ferguson of Oxford University) have dabbled in alternative histories. You know the kind of stuff, what if King Charles I hadn't been a brainless autocrat but a regular kind of a responsive monarch, might we have avoided Cromwell, the Civil War, regicide and a descent into vulgar democracy? These questions are fascinating, and invariably show how all the great left-wing events in history were accidents, while all the right-wing ones were an inevitable consequence of the way Man really is.
Even so, such speculations are as nothing when compared to the really great historical imponderable, what if we hadn't eaten the Ediacardians? What if we'd left them alone. What if (try to get inside this one), right now, the soft-bodied descendants - the evolutionary offspring - of those early peaceful slime-suckers, ran the planet?
Pessimists would, I suppose, reply that we'd all look like Vanessa Feltz, talk like Michael Howard, and spend most of the day watching Late Lunch. But - an optimist - I prefer to think that we would have become like beautiful rococo sofas, intelligent curtains, sentient champagne glasses, all of us growing to enormous, height, incorporating the most complex and satisfying patterns on our dulcet exteriors, living in pleasant sludge most of the year, and going - slowly - to the mountains for our holidays. There would be no wars, no money, and only the most unexerting form of sex.
But it didn't happen. And this is the second part of my meditation; what should we learn from the sad story of the Ediacarans? What, if anything, does it tell us about the nature of things? Sense organs and mouth parts, say the free marketeer or the realpolitiker; it's a trilobyte eats quilt world. She that survives will be she that gets the best mandibles and the sharpest eyes and uses them. He that dies out will be he that lies in ooze and expects his food to volunteer for duty. It shows the inevitable victory of Yang. Yes indeed, says Mr Atal Behari Vajpayee, and it also indicates the need for Ediacaran nations, like India, to develop their own mouth parts. There are a lot of predators out there.
No! say the Yinners (vegetarians, feminists, ecologists and Independent columnists). What is proved by this is that we have lost paradise at least once because of bad old predatory behaviour. And just because things have always been like this, is no reason that they always should be. Let us reflect upon the fate of the Ediacarans and resolve that it shall never, ever happen again. Blessed are the meek.