Then things get more complicated.
Evolution begins to happen. The fittest survive, pretty much the way Charles Darwin figured it out as he fondled his captive finches on board the Beagle. The plants go on making appetizing chemicals for the animals to feast on, and the animals go on feasting on the plants and on each other—but some plants accidentally develop traits that give their predators trouble, and so those plants survive; and some animals learn tricks to get around those defenses. Later generations of animals develop senses to locate their prey more efficiently, and musculatures to catch it, and ultimately complex behavioral systems (like the web of a spider or the stalking of a great cat) that make their predation more and more successful. (Then, of course, the plants, or the herbivores, or the less successful predators begin to develop defense mechanisms of their own: the poisons in a shrub’s leaf, the quills of a porcupine, the fleet legs of a gazelle. ) The competition never stops getting more intense, and more sophisticated on all parts—until, finally, some of the creatures become “intelligent.” But they take a lot longer to evolve . . . and it took the Gateway prospectors a lot longer to find any of them, too.
In the myriad worlds that the Heechee had explored—and to which the human Gateway prospectors followed them hundreds of thousands of years later—all those basics of the evolution of life were played out a thousand times, with a thousand variations. The variations were sometimes quite surprising. For instance, Earthly plants have one conspicuous trait in common: they don’t move. But there wasn’t any reason why that trait had to be universal, and in fact it wasn’t. The Gateway prospectors found bushes that rolled from place to place, setting roots down to one side and pulling them up on the other, like slow-motion tumble-weeds as they sought the richest soils and the best access to groundwater and the surest sunlight. Then, too, Earthly animals don’t normally bother with photosynthesis. But in the seas of other worlds there were things like jellyfish that floated to the surface by day to generate their own hydrocarbons from the sun and the air, and then sank down to feast on algal things at night. Earthly corals stay in one place. Prospectors found some unearthly ones—or, at least, some unearthly things that looked more or less like corals—that flew apart into their component little animals when the coast was clear, to eat and mate, and then returned to form collective rockhard fortresses when the prowling marine predators approached.
Most of these things were useless to any prospector whose big interest was in making a fortune. A few were not. There was one good feature to finding an organism that was worth something, and that was that it was an easy import. You didn’t have to bring tons of material back to Gateway. All you had to do was bring enough of some plant or animal back to breed others back on Earth, since living things were glad to reproduce themselves for you anywhere.
The zoos of Earth began to expand, and so did Earth’s aquaria, and its pet stores. Every fashionable family was sure to own its exotic windowbox of alien ferns, or its furry little pet from the planet of some other star.
Before the Gateway prospectors could make an honest buck in the pet trade, though, they had to find the living things in the first place. That wasn’t easy. Even when life was apparently possible, sometimes it was there, and sometimes it was not. The way to check for that was to look for chemical signatures in the atmosphere. (Oh, yes, the hopefully life-bearing planet had to possess an atmosphere, too, but that wasn’t a serious constraint. Most planets in the habitable zone did.) If the atmosphere turned out to contain reactive gases that hadn’t reacted—say, if it held free oxygen, with reducing substances like carbon or iron somewhere availably around—then it stood to reason that something must be continually replenishing those gases. That something was probably, in some sense, alive.
(Later on the prospectors found there were exceptions to these simple rules . . . but not many.)
The very first planet that turned out to have living things on it was a solid ten when studied from orbit. Almost everything was there: blue skies, blue seas, fleecy white clouds and plenty of oxygen—meaning some antientropic (i. e. living) thing to keep it that way.
Prospectors Anatol and Sherba Mirsky and their partner, Leonie Tilden, slapped each other’s backs in exultation as they prepared to land. It was their first mission—and they’d hit the jackpot right away.
Naturally they celebrated. They opened the one bottle of wine they’d brought along. Ceremonially they made a recording announcing their discovery, punctuating it with the pop of the wine cork. They called the planet New Earth. Everything was going their way. They even thought it likely that they could figure out just where they were in the galaxy (a kind of knowledge usually hidden from the early Gateway prospectors, because there weren’t any road signs on the way). But they had spotted the Magellanic Clouds in one direction and the Andromeda Nebula in another, and in still a third direction there was a tight, bright cluster that they were nearly sure was the Pleiades.
The celebration was a bit premature. It had not occurred to them that one interesting color was missing in their view of New Earth from space, and that color was green.
When Sherba Mirsky and Leonie Tilden went down to the surface of New Earth in the lander, what they landed on was bare rock. Nothing grew there. Nothing moved. Nothing flew in the sky. There were no flowering plants. There were no plants at all, at their elevation; there wasn’t any soil for them to grow in. Soil hadn’t reached those parts of the world yet.
It was only one more disappointment to find that there wasn’t much oxygen in its air, either—enough for a qualitative determination from orbit, yes, but nowhere near enough to breathe. For, although there certainly was life on New Earth, there just wasn’t much of it yet. Most of what there was lived in the coastal shallows, with a few hardy adventurers just making a start in colonizing the shores—simple prokaryotic and eukaryotic denizens of the sludgy seas, with a few scraggly, mossy things that had struggled out onto the littoral.
The trouble with New Earth was that it was a lot too new. It would take a billion years or so to get really interesting—or to pay Tilden, the Mirskys, and the Gateway Corporation back for the trouble of looking it over.
Although it was planets that offered profits, planets were also the places where it was easiest to get killed. As long as a Gateway prospector stayed inside his ship he was well protected against most of the dangers of star wandering. It was when he landed that he exposed himself to unknown environments . . . and often very hostile ones.
For example, there was:
MISSION PRETTY POISON
A fifty-year-old Venezuelan named Juan Mendoza Santamaria was the first Gateway prospector to discover a really nice-looking planet. It had taken him forty-three days to get there, all alone in a One. That was well within his margins. He was not likely to run out of air, food, or water. What he worried about running out of was money. Mendoza had spent the last of his credits on a farewell party before he left the asteroid. If he came back empty-handed to Gateway his future was bleak. So he crossed himself and whispered a prayer of gratitude as he stepped out of his lander onto the alien soil.
He was grateful, but he wasn’t stupid. Therefore he was also cautious. Mendoza knew very well that if anything went wrong he was in serious trouble. There was no one within many light-years who could help him—in fact, there wasn’t anybody, anywhere, who even knew where he was. So he wore his space suit at all times on the surface of the planet, and that turned out to be very fortunate for Juan Mendoza.