Is there a term for the valid assumption that a sufficiently complex and refined organ must be the result of natural selection on a large time scale?
Example: A biologist exists in a world where nothing has eyes. They find a creature with an eye as developed as a modern mammal's in our reality. Assuming this biologist understood what the eye was able to do as far as limiting and focusing incoming light and sending visual information to the brain, etc - it would go without saying that this was a gradually evolved system.
It would be impossible for a parent from a completely eyeless ancestry to spawn a child that had the equivalent of a fully developed modern mammalian eye, both because of the statistically improbability of that happening, and possibly even because of limitations in the way dna works.
Is there a word for this assumption? e.g. "As per the Axiom of Reliable Intuitive Ancestry Determination for Sufficiently Complex and Refined Traits, we will start our genetic research confident that the eye must be the result of iterative natural selection on a large scale of time."
Preferably a term that acknowledges the validity or reliability of this assumption when it comes to very complex and refined organs or systems, such as the eye, the brain, or the circulatory system.