[muawiyah]

And, you are coming close to hitting on the head the problem of "Natural Selection". It's certainly invisible, and it may involve being an eater, or being eaten, or maybe not at all (does DNA care if it's eaten?).

Gad.

[atlaw]

To the extent that you are suggesting that "natural selection" is a tautology, here is an interesting reply --

http://talkorigins.org/faqs/evolphil/tautology.html