Being cold blooded and living “wholly in water” are also requirements.
Comment on Not impressed
grue@lemmy.world 2 weeks agoOf course there’s such a thing as a fish! A fish is any swimming vertebrate (or its descendant), such as a tuna, or a duck, or a human.
runner_g@lemmy.blahaj.zone 2 weeks ago
grue@lemmy.world 2 weeks ago
Nah, phylogenetically speaking, all descendants of fish must also be fish, by definition. Therefore, “being cold blooded” cannot also be a criterion (not that it would work anyway since tuna are warm blooded, BTW, and nobody would argue tuna aren’t fish).
The “living wholly in water” criterion actually works, though: land-fish (e.g. humans) live inside a bag of water that we carry with us.
DragonTypeWyvern@midwest.social 2 weeks ago
You believe in cladistics or you don’t, cowards!