More centuries passed. Human ships again improved. A thousand light-years became a short journey. Explorers reached the Galaxy's very edge, and looked estimatingly across the emptiness toward other island universes. There were colonies in the Milky Way. There were freight-lines between star-clusters, and the commercial center of human affairs shifted some hundreds of parsecs toward the Rim. There were many worlds where the schools painstakingly taught the children what Earth was, and where, and that all other worlds had been populated from it. And the schools repeated, too, the one lesson that humankind seemed genuinely to have learned. That the secret of peace is freedom, and the secret of freedom is to be able to move away from people with whom you do not agree. There were no crowded worlds any more. But human beings love children, and they have them. And children grow up and need room. So more worlds had to be looked out for. They weren't urgently needed yet, but they would be.
Therefore, nearly a thousand years after the _Orana_, the Ecology-Ship _Ludred_ swam to the planet from space and landed on it. It was a gigantic ship of highly improbable purpose. First of all, it checked on the consequences of the _Orana's_ visit.
They were highly satisfactory, from a technical point of view. Now there was soil which swarmed with minute living things. There were fungi which throve monstrously. The seas stank of minuscule life-forms. There were even some novelties, developed by the strictly local conditions. There were, for example, paramoecia as big as grapes, and yeasts had increased in size until they bore flowers visible to the naked eye. The life on the planet was not aboriginal, though. All of it was descended and adapted and modified from the microörganisms planted by the seed-ship whose hulk was long since rust, and whose crew were merely names in genealogies--if that.
The _Ludred_ stayed on the planet a considerably longer time than either of the ships that had visited it before. It dropped the seeds of plants. It broadcast innumerable varieties of things which should take root and grow. In some places it deliberately seeded the stinking soil. It put marine plants in the oceans. It put alpine plants on the high ground. And when all its stable varieties were set out it added plants which were genetically unstable. For generations to come they would throw sports, some of which should be especially suited to this planetary environment.