Amillennialist

That's a razor's edge you're treading. Observed similarities in form tell us nothing necessarily about descent. Correlation does not equal causation. And there is a vast difference between two lines of the same organism no longer being able to reproduce with each other and one form of Life changing into another, different form of Life. No one's ever seen -- nor will see -- either abiogenesis or newer, more complex forms of Life arising by only random, natural processes. But we have always and only seen Life arise from the same kind of Life (or its programs).