Dark Ararat - Brian Stableford [160]
Matthew paused, looking beyond the camera at the man holding it. Ike had been concentrating on the problem of keeping the camera steady, and didn’t immediately register the slight change of attitude. When he did, he took his eye away from ther viewfinder momentarily to acknowledge the contact. He couldn’t shrug his shoulders without shaking the image, so he contrived a gesture of reassurance with a forced smile.
Having cleared his throat Matthew went on.
“Well, the logical answer is that once an organism can obtain energy by eating, the extra margin of assistance to be gained from continuing to fix solar energy is too small to be worth keeping, so there’s no selective pressure to retain it. The number of animal species is, of course, limited by the fact that they all have to have something to eat, so there have to be lots of plants around in order to support any animal life at all, but the more animal life there is the more scope is opened up for animals that eat other animals. Plants can only dabble in eating animals if there are enormous numbers of plants around that don’t, and they find it difficult to compete with animals because they’re sedentary. If you’re an eater, it’s a great advantage to be able to get around—waiting for your food to come to you is obviously a second-best strategy—and an organism needs so much energy to get around that if it’s going to do that, it might as well be a specialist eater.
“So how come this world is so rich in organisms that have kept their ability to fix solar energy in spite of the fact that they can eat and get around? The purple worms don’t even seem to make strenuous efforts to get out into the sun when they can. They lurk in the shadows like any other stealthy predator. How can that make sense?
“Well, I can only see one way in which it might make sense. If the super-slugs keep chloroplast-analogues they don’t bother to use on a day-to-day basis, there must be times when they do need to use them. Rare times, maybe, but vital times—times when that energy-fixing capability is so vital that it’s carefully sustained through all the times when it’s not. And that’s where the exotic reproduction has to come in.”
He looked away as a sudden movement caught his eye, but it was only something falling from the canopy. He looked back before Ike moved the camera.
“The most important difference between life on Earth and life on Ararat, alias Tyre, is that sex isn’t the only way of shuffling the genetic deck so as to produce the variations on which natural selection works. Here, sex involves cells within a chimerical corpus rather than whole organisms. You could say that all the local organisms are actually small-scale colonies of continually cross-breeding individuals. And they’re probably all emortal. That doesn’t matter much to the simplest ones, because they never live long enough to die of old age; they always get eaten long before they reach the limits of their natural life spans. The more complicated ones are a different matter.”
Matthew hesitated again, but this time it was purely for dramatic effect. Ike understood that, and stayed focused.
“Earth’s ecosphere was shaped by what Bernal Delgado used to call the sex-death equation. The essence of life is reproduction, but there are two kinds of reproduction. There’s the kind by which organisms make new organisms and the kind by which organisms reproduce themselves. The cells of your body are continually replaced, so that every eight years or so there’s an entirely new you, almost as good as the old one but not quite. We humans—and I mean we in a narrow sense, because there’s a new human race on Earth now that doesn’t have this particular disadvantage—deteriorate like a chain of old-style photocopies, each image becoming