A short history of nearly everything - Bill Bryson [164]
There is still very little agreement about what these things were or how they lived. They had, as far as can be told, no mouth or anus with which to take in and discharge digestive materials, and no internal organs with which to process them along the way. “In life,” Fortey says, “most of them probably simply lay upon the surface of the sandy sediment, like soft, structureless and inanimate flatfish.” At their liveliest, they were no more complex than jellyfish. All the Ediacaran creatures were diploblastic, meaning they were built from two layers of tissue. With the exception of jellyfish, all animals today are triploblastic.
Some experts think they weren't animals at all, but more like plants or fungi. The distinctions between plant and animal are not always clear even now. The modern sponge spends its life fixed to a single spot and has no eyes or brain or beating heart, and yet is an animal. “When we go back to the Precambrian the differences between plants and animals were probably even less clear,” says Fortey. “There isn't any rule that says you have to be demonstrably one or the other.”
Nor is it agreed that the Ediacaran organisms are in any way ancestral to anything alive today (except possibly some jellyfish). Many authorities see them as a kind of failed experiment, a stab at complexity that didn't take, possibly because the sluggish Ediacaran organisms were devoured or outcompeted by the lither and more sophisticated animals of the Cambrian period.
“There is nothing closely similar alive today,” Fortey has written. “They are difficult to interpret as any kind of ancestors of what was to follow.”
The feeling was that ultimately they weren't terribly important to the development of life on Earth. Many authorities believe that there was a mass extermination at the Precambrian–Cambrian boundary and that all the Ediacaran creatures (except the uncertain jellyfish) failed to move on to the next phase. The real business of complex life, in other words, started with the Cambrian explosion. That's how Gould saw it in any case.
As for the revisions of the Burgess Shale fossils, almost at once people began to question the interpretations and, in particular, Gould's interpretation of the interpretations. “From the first there were a number of scientists who doubted the account that Steve Gould had presented, however much they admired the manner of its delivery,” Fortey wrote in Life. That is putting it mildly.
“If only Stephen Gould could think as clearly as he writes!” barked the Oxford academic Richard Dawkins in the opening line of a review (in the London Sunday Telegraph) of Wonderful Life. Dawkins acknowledged that the book was “unputdownable” and a “literary tour-de-force,” but accused Gould of engaging in a “grandiloquent and near-disingenuous” misrepresentation of the facts by suggesting that the Burgess revisions had stunned the paleontological community. “The view that he is attacking—that evolution marches inexorably toward a pinnacle such as man—has not been believed for 50 years,” Dawkins fumed.
And yet that was exactly the conclusion to which many general reviewers were drawn. One, writing in the New York Times Book Review, cheerfully suggested that as a result of Gould's book scientists “have been throwing out some preconceptions that they had not examined for generations. They are, reluctantly or enthusiastically, accepting the idea that humans are as much an accident of nature as a product of orderly development.”
But the real heat directed at Gould arose from the belief that many