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Reading the link, it appears most species of 'fish' have as most recent ancestor, some ancient sea sponge or something. They became what they are through indepe
by JoeAltmaier 4y ago
Reading the link, it appears most species of 'fish' have as most recent ancestor, some ancient sea sponge or something. They became what they are through independent evolutionary paths. It's called something like 'convergent evolution' and its a common thing, where environmental pressure causes wildly different original organisms to evolve to look and act nearly the some. It's true with fish, trees and I imagine other things.
See, just because they look about the same doesn't mean they share any common parentage.
- robbrown451 4y agoWell the common ancestor of all living fish would be more like a lancelet, which is nothing like a sea sponge. (it is bilaterally symmetrical and has a "notochord" which is like a primitive spinal chord. The main issue I have with the parent's comment is the idea that "most species" evolved independently. No, most species have a whole bunch of other species very closely related to them. There are a few major branches of fish, such as ray finned (most fish) and lobe finned, the taxanomic category of the latter also includes tetrapods, and only has a couple of species that are still actual fish, such as coelacanth and lungfish. And above that distinction, there are bony fish and cartilaginous fish, such as sharks and rays. But still, even if fish is not monophyletic, it is not polyphyletic, which means all things considered fish are "connected" to other fish. https://en.wikipedia.org/wiki/Evolution_of_fish#/media/File:Fish_evolution.png https://en.wikipedia.org/wiki/Evolution_of_fish#/media/File:...
- JoeAltmaier 4y agoAnother picture, with time scale: https://phys.org/newman/gfx/news/hires/2015/5649bb15633da.png https://phys.org/newman/gfx/news/hires/2015/5649bb15633da.pn...