• @[email protected]
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      2 years ago

      Since there isn’t really any agreed upon scientific definition what “a fish” is, it’s pretty much a perfect name

        • threelonmusketeers
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          42 years ago

          There is no sensible phylogenetic definition of “fish” which includes both trout and sharks but not humans.

          • Nepenthe
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            22 years ago

            Are sharks fish? Sharks are fish. They live in water, and use their gills to filter oxygen from the water.

            Seems pretty easy to me. Even lungfish have gills.

              • @[email protected]
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                32 years ago

                Do frogs have gills? The tadpole stage of frogs might be fish, but adult frogs aren’t fish.

                But, whether or not you want to consider axolotl and frogs fish, “gills” is a neat line that separates humans from trout and sharks.

                • @[email protected]
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                  2 years ago

                  Sure but what the OP was saying is that these common definitions of fish are paraphyletic. In order to make a monophyletic group including everything we call fish, we’d have to include humans, birds, lizards, etc. And going by the water-and-gills definition, this group would include things we tend not to call fish like crabs, amphibians, sea slugs, some insects… Not to mention that gills have evolved multiple times. And something like a frog being not a fish but it’s larvae being fish doesn’t make sense for cladistics.

                  separates humans from trout

                  I’m a little bit curious about why you specifically selected humans to be differentiated from fish

                  • @[email protected]
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                    12 years ago

                    Because:

                    There is no sensible phylogenetic definition of “fish” which includes both trout and sharks but not humans.

                    Gills.