You can’t evolve out of a clade. Humans didn’t stop being apes, haplerines, primates, mammals, therapsids, etc. at any point, because a clade includes all descendants of a common ancestor.
so all tetrapods are bony fish, not fish, because fish is a non cladistic category of animals that roughly means animal you think of when you think of fish
Yep, that would be the fish clade. The only way to draw a clade that includes all extant animals we’d consider fish is to include all of vertebrata. You could also consider the fish clade to just be ray-finned fishes if you want, but then sharks, rays, coelacanths, mudskippers, etc would not be fish, which seems absurd to me (but is also cladistically valid).
But fish are not a clade. Mice are not fish. Birds are not fish. I don’t know how else to explain it to you. Do you understand that there can be terms for groups of living things that are not clades or that have no scientific basis whatsoever? Did you know that there is no difference between frogs and toads except that, broadly speaking, we call the ugly warty ones toads?
I can find plenty of places with authority that describe Vertebrata as a clade. I can’t find any that describe fish as a clade.
If fish are a clade, people uninfluenced by internet memery would refer to all vertebrates as fish, yet I’m pretty sure this also doesn’t happen. If the guy in the restaurant today had told me that the varying fish on the menu was not sea bream, but a sodding gecko, I’d have been pretty miffed.
If fish are a clade, people uninfluenced by internet memery would refer to all vertebrates as fish, yet I’m pretty sure this also doesn’t happen. If the guy in the restaurant today had told me that the varying fish on the menu was not sea bream, but a sodding gecko, I’d have been pretty miffed.
I’m confused why you think the common usage of the word fish has any relevance to a discussion about choosing a definition for a fish clade. I’m not making the claim that this is how people use fish in common usage. My claim is that if you want to draw a fish clade, the only consistent way to do that is to include all of vertebrata. Scientists defining clades don’t concern themselves with how laymen group animals together, because that would be dumb.
You are right, but… Then there’s logic. People say cartilaginous fish (like sharks) are fish and bony fish (like carps) are fish, the only clade that contains both is the vertebrates, hence language is dumb and we all should hug each other.
This is a popular definition of a species*, but you’re applying it to a class**. Humans can’t breed with other apes, but we are apes. Biological classification (fish vs whales) is based on evolutionary relationships and traits, not whether two animals can interbreed.
Cladistically, whales are not fish because “fish” isn’t a clade. Fish are an everyday label, not a clean scientific clade or rank.
* - this is a very limited definition of species
** - fish really aren’t a class, but that’s how it’s taught in grade school
No, modern cladistics is not like that at all, because fish do not form a clade. Fish are non-tetrapod vertebrates; humans are tetrapods, hence vertebrates but not fish.
I’m not sure if you’re missing that the whole point is that trying to treat “common” terms like scientific terms creates logical conundrums like this because nature isn’t about clean lines and groups.
The whole point of saying “Whales are fish” and things like that is as a reminder that human classification (even detailed and precision-focused scientific classification) is still just a human construct we use to order the world around us. It’s arbitrary what is and is not a fish.
In fact we see science educators bring this up so much, I think, because it’s important to be able to answer “why don’t the scientists just call them fish?” when discussing ray finned fishes or something like that and this discussion is helpful practice for that.
Yes it’s arbitrary what is and is not a fish… So why pretend that the category is something other than what it is? Noone who isn’t being weird about it on the internet thinks all vertebrates are fish.
Rar! Grrr! Snarl! Angry stomping noises!
Whales evolved from fish, but ceased being fish when they could no longer breed with them.
I didn’t want to leave you with no angry commenys.
You can’t evolve out of a clade. Humans didn’t stop being apes, haplerines, primates, mammals, therapsids, etc. at any point, because a clade includes all descendants of a common ancestor.
so all tetrapods are bony fish, not fish, because fish is a non cladistic category of animals that roughly means animal you think of when you think of fish
But fish are not a clade. The clade you’re thinking of is vertebrates.
Yep, that would be the fish clade. The only way to draw a clade that includes all extant animals we’d consider fish is to include all of vertebrata. You could also consider the fish clade to just be ray-finned fishes if you want, but then sharks, rays, coelacanths, mudskippers, etc would not be fish, which seems absurd to me (but is also cladistically valid).
But fish are not a clade. Mice are not fish. Birds are not fish. I don’t know how else to explain it to you. Do you understand that there can be terms for groups of living things that are not clades or that have no scientific basis whatsoever? Did you know that there is no difference between frogs and toads except that, broadly speaking, we call the ugly warty ones toads?
Sure they are, smallest clade that includes coelacanths and hagfish, which would be vertebrata.
I can find plenty of places with authority that describe Vertebrata as a clade. I can’t find any that describe fish as a clade.
If fish are a clade, people uninfluenced by internet memery would refer to all vertebrates as fish, yet I’m pretty sure this also doesn’t happen. If the guy in the restaurant today had told me that the varying fish on the menu was not sea bream, but a sodding gecko, I’d have been pretty miffed.
I’m confused why you think the common usage of the word fish has any relevance to a discussion about choosing a definition for a fish clade. I’m not making the claim that this is how people use fish in common usage. My claim is that if you want to draw a fish clade, the only consistent way to do that is to include all of vertebrata. Scientists defining clades don’t concern themselves with how laymen group animals together, because that would be dumb.
You are right, but… Then there’s logic. People say cartilaginous fish (like sharks) are fish and bony fish (like carps) are fish, the only clade that contains both is the vertebrates, hence language is dumb and we all should hug each other.
WHALE IS FISH, NO HUG (unless…?)
So salmon is not fish? Salmon can breed with other salmon but not other fish…
Up comes Diogenes with a fish insemination machine shouting: “Behold, a fish!”
Salmon are fish. Salmon can breed with salmon, so salmon can breed with fish. Ergo salmon are fish.
https://yourlogicalfallacyis.com/begging-the-question
This is a popular definition of a species*, but you’re applying it to a class**. Humans can’t breed with other apes, but we are apes. Biological classification (fish vs whales) is based on evolutionary relationships and traits, not whether two animals can interbreed.
Cladistically, whales are not fish because “fish” isn’t a clade. Fish are an everyday label, not a clean scientific clade or rank.
* - this is a very limited definition of species
** - fish really aren’t a class, but that’s how it’s taught in grade school
Once a fish, always a fish. Modern cladistics is weird like that. Unironically, humans are fish 🐟
No, modern cladistics is not like that at all, because fish do not form a clade. Fish are non-tetrapod vertebrates; humans are tetrapods, hence vertebrates but not fish.
I’m not sure if you’re missing that the whole point is that trying to treat “common” terms like scientific terms creates logical conundrums like this because nature isn’t about clean lines and groups.
The whole point of saying “Whales are fish” and things like that is as a reminder that human classification (even detailed and precision-focused scientific classification) is still just a human construct we use to order the world around us. It’s arbitrary what is and is not a fish.
In fact we see science educators bring this up so much, I think, because it’s important to be able to answer “why don’t the scientists just call them fish?” when discussing ray finned fishes or something like that and this discussion is helpful practice for that.
Yes it’s arbitrary what is and is not a fish… So why pretend that the category is something other than what it is? Noone who isn’t being weird about it on the internet thinks all vertebrates are fish.