No, really. Ecosystems.
The work that shows this off to best advantage is Schmitz's novel, The Demon Breed (full text), but it is a critical element of this week's story as well. An excerpt:
He put his left hand up to his face, and Ilf saw he was wearing a wrist-talker. "Het," Mr. Terokaw said to the talker without taking his eyes off Riquol Cholm, "you are aware, I believe, that the children are with us in the house?"
The wrist-talker made murmuring sounds for a few seconds, then stopped.
"Yes," Mr. Terokaw said. "There should be no problem about it. But let me know if you see somebody approaching the area . . . " He put his hand back down on the table. "Mr. Bliman, please continue."
Mr. Bliman cleared his throat again.
"Mr. Kugus Ovin," he said, "is now officially recorded as the parent by adoption of his niece, Auris Luteel. Since Auris has not yet reached the age where her formal consent to this action would be required, the matter is settled."
"Meaning," Mr. Terokaw added, "that Kugus can act for Auris in such affairs as selling the cutting rights on this tree farm. Mr. Cholm, if you are thinking of taking legal action against us, forget it. You may have had certain papers purporting to show that the girl was your adopted child filed away in the deposit vault of a bank. If so, those papers have been destroyed. With enough money, many things become possible. Neither you nor Mrs. Cholm nor the two children will do or say anything that might cause trouble to me. Since you have made no rash moves, Mr. Bliman will now use an instrument to put you and Mrs. Cholm painlessly to sleep for the few hours required to get you off this planet. Later, if you should be questioned in connection with this situation, you will say about it only what certain psychological experts will have impressed on you to say, and within a few months, nobody will be taking any further interest whatever in what is happening here today.
"Please do not think that I am a cruel man. I am not. I merely take what steps are required to carry out my purpose. Mr. Bliman, please proceed!"
Ilf felt a quiver of terror. Uncle Kugus was holding his wrist with one hand and Auris' wrist with the other, smiling reassuringly down at them. Ilf darted a glance over to Auris' face. She looked as white as his grandparents but she was making no attempt to squirm away from Kugus, so Ilf stayed quiet, too. Mr. Bliman stood up, looking more like a fierce bird of prey than ever, and stalked over to Riquol Cholm, holding something in his hand that looked unpleasantly like another gun. Ilf shut his eyes. There was a moment of silence, then Mr. Terokaw said, "Catch him before he falls out of the chair. Mrs. Cholm, if you will just settle back comfortably . . . "