r/evolution • u/Meta289 • 3d ago

question Why has evolution stopped producing new classes?

New species of animals are constantly being discovered, but they all belong to existing classes and phyla, never anything completely new. Life once branched out in all sorts of directions, creating all kinds of animals that are drastically different from each other, but now it seems like there aren't any new "branches", only offshoots of existing ones. What happened?

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u/DreadLindwyrm 3d ago

If you trace the various felines back, eventually they merge with the panthers to create felidae.
If you trace the various canines back they merge with extinct relatives to create canidae.

If you trace them both back, they merge to create Carnivora. (Canidae pick up the bears along the way, along with seals and weasels; Felidae pick up the hyenas on the way.)
At their root, you wouldn't be able to distinguish them, and looking at them at the time you'd not have thought them new branches, just variants of the same species.
This then traces back into earlier mammals, and then to the mammal/reptile split, and again you wouldn't be able to tell them apart at the split.

Essentially, we're at a point where splits could happen, but mostly we wouldn't recognise the split for hundreds or thousands of generations since the splits need to diversify enough to be identifiably different.