Free The Gates of Eden: A Science Fiction Novel by Brian Stableford

fact were, in evolutionary terms, I wasn’t entirely certain. The fact that the Ariadne ’s resources had so far managed to turn up no evidence of any vertebrate creature more “advanced” than a frog didn’t for one moment convince me that there was no such creature. There was a temptation to embrace the line of argument that because Naxos was a more peaceful world than Earth, natural selection would not have been as powerful an agent of change, and that one would therefore expect its life-system to retain many supposedly primitive features. That could easily give one an excuse for believing that life on Naxos had only just learned to operate on land as well as on water, and that boring, unspecialized amphibians were the order of the day. I didn’t like that line of argument much, though, despite its superficial plausibility.
    There were two reasons I didn’t like it. The first was to do with the assumption that the pace of evolution on Earth had been quickened by the tendency of the surface to undergo constant and sometimes catastrophic change. Evolution may well be the survival of the fittest in the struggle for existence, but that doesn’t mean that the harder creatures have to struggle against the vicissitudes of nature the more progress they’ll make. Environmental catastrophes aren’t necessarily inclined toward eugenics—they’re too indiscriminate. One could argue that rapid environmental change is bad for evolutionary progress because it causes too many species to become extinct, resulting in frequent massive gene-loss from the system. We tend to assume that what happened on Earth is the “natural progression,” especially now we know that what happened on Calicos was virtually a carbon copy. But what about all the other Earthlike worlds, where the hostility of the environment is such that life can only eke out the most miserable of existences, as organic glop, or primeval soup, or whatever you care to call it?
    It’s arguable that the really progressive changes in evolution—toward greater organization and complexity, toward greater individual adaptability and all the range of behavioral abilities up to and including intelligence—come not from the testing of a hostile environment but from intraspecific competition and selection. My theory, at least, was that the really vital changes in Earth’s evolutionary past happened not as a result of catastrophes and waves of extinction, but during the geologically quiet times, when species had things relatively easy, when mutations weren’t penalized so heavily and gene pools could diversify—when there was time, in fact, for nature to conduct her experiments.
    On that logic, there was no need to expect Naxos to be “primitive” relative to Earth. There was reason enough, no doubt, to expect it to be different, but to jump to the conclusion that it was on the same evolutionary path but merely happened to have got stuck at the amphibian “stage” seemed to me to be unjustified. Maybe all life on Naxos—all complex animal life, anyhow— was amphibious...but if so, I reasoned, it needn’t be because there was nothing there more complex than a frog. It might, instead, be because there was so much water on Naxos, so abundantly distributed, that there was no great advantage in not being amphibious.
    The second reason that I didn’t like the evolutionary-arrest hypothesis was the fact that (as far as I could interpret the data) it didn’t seem to hold for the plants. They weren’t stuck in a rut to the extent that they provided a convincing analogue of the vegetation of the Devonian. There were lots of flowering plants, many kinds of trees, and—most significant—lots of different kinds of grass. The insects, too, were very various. Maybe there were no reptiles, which had learned to lay hard-shelled eggs that could survive desiccation. Maybe there were no birds. But to me, that only implied that the complexity of vertebrate life must be expressed