Evolution (of species) is the result of Natural Selection happening over many generations as a species responds to changing environmental pressures.
Natural Selection is the result of random non-fatal mutations which can occur when a cell clones itself (e.g. mitosis, meiosis).

If the mutation did not cause the offspring to be infertile (or in some other way prevent it from reproducing), then it goes into the gene pool.

The thing that produces the most fertile children has higher chance of long-term influence on the species as a whole. If it happens to also be a bit taller or bear majestic plumage or be able so survive the pending ice-age or whatever... so it goes. Those traits may or may not have anything to do with the thriving of the species.


So... given unknown environmental pressures... seemingly infinite variability and heartiness in forms of life... the sheer number of planetary systems in the galaxy...

Obviously Klingons or gtfo.


Do I have you right?