Evolution

People were stumbling away from the feeding grounds now. Some were carrying the heavy seeds of the Tree, huge pods as large as their own heads. Like the frogs, this strange day was the Tree’s once-a-century opportunity to have the seeds of its next generation buried for it by its armies of symbiotes.

Ultimate saw Cactus chasing a small, scuttling lizard with a plump tail full of stored fat.

Cactus had been born about the same time as Ultimate, and as they had grown up they had learned about the world together, sharing, competing, fighting. Cactus was small and round. This was unusual for her people, who were generally skinny and long limbed, the better to lose their body’s heat — and she was prickly tempered, indeed like a cactus. Cactus was a kind of companion, even a sister, but she wasn’t Ultimate’s friend. You had to be able to see somebody else’s point of view to call them a friend, and that ability had long been given up. People didn’t have friends these days — no friends apart from the Tree.

Ultimate wanted to follow Cactus, but she was distracted. Suddenly she longed for salt. That was the Tree’s message to her, imprinted in the organic chemistry it had fed her while in the cocoon. The Tree needed salt. And it was up to her to find it. She remembered where a salt bed was, a few hundred meters away. She was helplessly drawn that way.

But in that direction stood the sphere, that enigmatic ball of black and purple that lowered silently over the teeming landscape.

She hesitated, caught between conflicting impulses. She knew the sphere was wrong. The great tide of human intelligence had long withdrawn, but the people had retained a good understanding of the land, its geography, and resources: efficient foraging was an essential skill if you were to find food and water in this desperately arid landscape. So she understood very well that the sphere shouldn’t be here. But that was the way to the salt.

Despite her unease, she set off.

The salt lick was almost at the foot of the sphere. She saw how mud had lapped up against its oddly gleaming surface. She tried to ignore the sphere, and began to scrabble in the sticky dirt.

There was no shortage of salt. A hundred million years ago, as the continents had danced toward their spontaneous assembly of this New Pangaea, a great inland sea had formed over much of North America. It had become landlocked, leaving only scattered lakes of brine. But that vanishing sea had left behind a vast bed of salt deposits, a shining plain that had stretched for hundreds of kilometers. The salt bed had been covered by debris washed down from the ruins of the fast-eroding mountains, and now lay buried under meters of rust-red sand, but it was still there.

Before long she had made a hole as deep as her arm could reach, and she was bringing up handfuls of dirt laced with gray-white salt. She chewed on the dirt, letting the salt crystals melt in her mouth, and spitting out the sand. With the salt in her belly, stored for later transmission to the Tree, Ultimate was released from her compulsion.

And again she became aware of the sphere. It had moved from where she had first seen it. And it hovered above the ground; a finger’s-width of light could be seen beneath it.

She approached the sphere, walking on her hind feet and her knuckles, a dim curiosity alight in her eyes. Her fear wasn’t strong. There were few novelties in her desert world. But likewise there were few threats. In a landscape like a tabletop, predators had a difficult time sneaking up on even the slowest and dullest of victims.

With a tentative fingertip she stroked the sphere’s surface. It was neither warm nor cold. It was smooth, smoother than anything she had felt before. The hairs on her hand prickled, as if charged. And she could smell something, a smell like the quintessence of the desert itself, an electric smell of scorching, of burning, of dryness.

The burnt-metal smell was in fact the result of exposure to hard vacuum: a legacy of space.

Their foraging done, one by one the people returned to the Tree, climbed into its branches, and folded themselves securely inside its leaves.

Ultimate pulled leathery leaves around her body. The belly-root snaked out quickly, probing for the valve on her stomach, and nestled into her like a reattached umbilical. As her salt-laden fluids began to circulate into the Tree, so Ultimate was rewarded by a soothing sense of security, of peace, of lightness. This mood was induced by chemicals leaked into her body as she exchanged blood for Tree sap, but it was no less comforting for that. This was her immediate reward for feeding the Tree, just as her longer-term reward was life itself. The Tree did not take without giving. Posthuman and Tree were neither of them parasites on the other. This was a true symbiosis.

But there was something wrong. Ultimate felt uneasy, wordlessly disturbed.