Take “Spider” for example, that is a fairly well definied term for all animals in the order “Araneae”. But that doesn’t really work for the term “Fish”. There a many dozens of completely different orders with thousands of species that are refered to as “Fish”. It’s a bit like saying “thing that swims in the water”.
You’ll get a lot of squids, seeweed, and all kinds of stuff with that, but not a bad start for a 5 year old. She’s way on her way to being a taxonomist :D
When organizing the big family tree of everything that’s alive, you use clades, which means a group that all of the individuals in it have the same common ancestor. E.g. All vertebrates, wether mammals, reptiles, etc, have the same vertebrate ancestor. Mammals also share the same tetrapod ancestor, so they’re all tetrapods.
Fish doesn’t work like that, because we don’t count all the its ancestors as fish (tetrapods have a common bony fish ancestor, for example, but you wouldn’t call a parrot a fish). But you know what a fish is. We call this a paraphyletic group.
ELI22 undergrad degree?
Take “Spider” for example, that is a fairly well definied term for all animals in the order “Araneae”. But that doesn’t really work for the term “Fish”. There a many dozens of completely different orders with thousands of species that are refered to as “Fish”. It’s a bit like saying “thing that swims in the water”.
My 5 year old says “thing that swims in the ocean/lake with exception of mamals is good fish”
You’ll get a lot of squids, seeweed, and all kinds of stuff with that, but not a bad start for a 5 year old. She’s way on her way to being a taxonomist :D
Then an axelotal is a fish,
When organizing the big family tree of everything that’s alive, you use clades, which means a group that all of the individuals in it have the same common ancestor. E.g. All vertebrates, wether mammals, reptiles, etc, have the same vertebrate ancestor. Mammals also share the same tetrapod ancestor, so they’re all tetrapods.
Fish doesn’t work like that, because we don’t count all the its ancestors as fish (tetrapods have a common bony fish ancestor, for example, but you wouldn’t call a parrot a fish). But you know what a fish is. We call this a paraphyletic group.