An increased likelihood of evolving certain features?
I enjoy learning about science and genetics, despite my irrelevant education.
One fact which caught my attention today at the Harvard Museum of Natural History, which I recommend, was that among echinoderms, the distinctive 5-directional, or pentaradial symmetry arose three separate times.
If it has not, at least commonly, arisen in other phyla, I thought then that something in the precursor to a pentaradial organism could predispose it to the sort of mutation that would result in that body shape.
Same thought of course for other traits in other organisms.
At one level this must be true—an animal with fingers is more likely to grow an extra finger than a bee is. Have I been thinking about anything interesting, or is it just this obvious fact magnified over time?