PhosphorusDecree wrote:
Most people seem to use a "folk classification" for everyday speech in which mammals are called "animals", while birds, reptiles, spiders, tube-worms etc. are considered to be something other than animals. Think how often you hear the phrase "animals and birds"!
My favourite bit of biological pedantry is to do with cladistics and fish. A clade includes ALL descendants of a common ancestor, which can really mess with our categories. It's where the idea that "birds ARE dinosaurs" comes from. But it gets even better.
Leave invertebrates with names ending in "-fish" aside for the moment, and try to draw up a monophyletic clade called "Fish" that includes both sharks and salmon. You can do it, but "Fish" will also include the reptiles*, amphibians, birds and mammals, all of which are descended from an ancestor smack bang in the middle of the fish family tree. So.... actually, Miss, a whale IS a kind of fish. And so's a goldfinch.
*"....
Well...um yeah. If you wanna get THAT technical about it then... yes, you and I (humans) are a type of "fish", and so are dogs, cats, kangaroos, lizards, frogs, and sparrows. All land vertebrate animals (ie quadapedes) are descended from a ancestor that was a lobe finned boney water breathing fish. Likewise all land verebrates that returned to the sea in evolution- and became secondarily marine- are also "fish" ( penguins, marine iguanas, extinct plesiosaurs, seals, sea lions, manatees, and ..yes whales..are all "fish"( in the same sense that humans are "fish".
30 May 2019, 9:13 am
