I don’t think I was ever taught about clades and I am confused by them. Are they there to challenge the hierarchy of Domain, Kingdom, Phylum, etc. etc. or are they something else? Have they replaced any of those D.,K.,P., C., O., F., G., S.? Should I italicize clades?
Please help. Thanks!
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A clade is a branch of an evolutionary tree. Modern classification generally tries to make named groups in a traditional hierarchy (families, etc) correspond to a single clade. However not every clade has to be named or assigned to a group in the formal taxonomic hierarchy.
A clade is a group of organisms that is composed of all of the descendants of the group’s common ancestor.
So, for example, you, all of your siblings form a clade because you all share common ancestor, your parents, and every descendant of them is in the group.
Another clade would be you, all of your siblings and all of your cousins, because you all share the same grandparents. But the group of you and your cousins, but not your siblings isn’t a clade, because there are descendants that are excluded.
An order, phylum, etc. is usually a clade, but not always because some categories were made before the evolutionary history of the organisms was understood. Though as we learn more, scientists re-categorize organisms.
A clade is any group containing all the descendants of a particular ancestral creature.
For example, at some far distant point there was a species of small furry creatures that was the ancestor to all mammals, but not the ancestor to anything else. This makes mammals a clade, as it is the group containing all of that species’s descendents.
Clades come in all sizes, for example primates are all the descendants of a common ancestor, so that is another smaller clade that exists within the clade of mammals.
However, there are animal-groups that we commonly think about aren’t clades. There was never a creature that was ancestor to all fish and only the ancestor to fish. If you go back to the creature that was common ancestor to sharks and salmon, it turns out to also be the ancestor to a lot of non-fish creatures (for example, us). So fish aren’t a clade.
> Are they there to challenge the hierarchy of Domain, Kingdom, Phylum, etc. etc. or are they something else?
As other commenters have mentioned, a ‘clade’ is just any group of all organisms who share a particular common ancestor. Each of those traditional levels is (meant to be) a clade. AIUI a lot of biologists now prefer to just use ‘clade’ instead of any of those traditional hierarchical levels, though, because it turns out there’s *waaaaaaay* more branching in the actual tree of evolutionary history than a limited set of named levels could ever possibly handle, and different modern species can find themselves at *very different* depths in that tree.
Each of these answers combined with some youtube videos with diagrams have helped me understand that it’s not that earth shattering as I thought it was. As long as the DKPCOFGS still fit, most of the time, then it’s all good. I just need to learn more.
Thank you all for your help.
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