But, it simply isn't true: my worldview would only be minorly shifted if I discovered that the Tree of Life actually consisted of a dozen separate Trees of Life. But, if ToE were false, my entire worldview would collapse and I would have to start completely over.
I don't actually see why it would shift at all (ok, maybe 0.00001 %).
A recent suggestion for finding alien (not us) life forms is fascinating. Instead of the struggle to find them on Mars or Europa it has been suggested that we look here on Earth. If they are alien enough (not DNA based or a DNA pattern for coding that is very diffent from ours (ours being all life we have looked at so far)) we might not recognize them if we tripped over them. ("tripped" is an exaggeration -- they would be unicellular almost for sure).
The idea of a
single LCA (last common ancestor) has nothing at all to do with worldviews as I see it. It is simply what we see from our examinations of life forms
so far. I would be
delighted if we stumbled over a separate lineage!!! It would be wonderful and exciting!!!! And it would change nothing at the "worldview" level.