“You’re all familiar with Xenklev’s Law of evolution as it pertains to biological life forms, but did you know that can also apply to planetary development?” asked the teacher.
“As with a virus, if too lethal, it can kill the host before it gets a chance to spread. An evolutionary dead end. The same can be said of planetary ecologies.”
The image changed to a blue green world of mostly water. “Until a few cycles ago, this planet was heavily populated by its dominant species, a carbon based bipedal mammal. They had evolved large brains capable of abstraction, logical reasoning and foresight. Yet they were wiped out due to conflicts over diminishing resources, and a mismanaged ecology. Like the bacterium, they have killed their host before they could spread their infection to the rest of the cosmos.”

A student asked “If their brains were capable of foresight, could they not have seen the consequences of their actions?”

“Possibly” admitted the teacher. “But it does appear as though that never occurred to them.”