I suppose we are using different definitions of “real.”
Not sure it’s worth hashing that out.
Well, I think that he is (though he doesn’t realize this himself) hinting at the arbitrariness of assigning names to clades. Like how he says there; “Even here we have to decide on how far back that clade should go” which doesn’t make much sense. We don’t have to decide ‘how far back a clade goes’, since a clade starts with the common ancestor by definition. But what I suspect he means is that, if we were to look at the entire sequence of ancestors, it is arbitrary to decide how far back along this sequence of ancestor we have to go before we say “that ancestor right here, that ancestor + all descendants are fish”. But what he keeps missing is that for every ancestor, you can define a clade, and each clade is not arbitrary. So it doesn’t matter which ancestor you would call the “first fish”. One ancestor further back or one ancestor further down, both clades would still be real. The ONLY difference between these two scenarios to what clade gets the name ‘fish’, and this is why I keep pointing out to him that this arbitrariness he keeps talking about is all about assigning names to clades. (I hope I made this now clear to you @Rumraket).
A rose by any other name . . .
Perhaps the title should be, “Why Humans are Fish If We Use Cladistics”. In context, we are reacting to Neil Shubin’s “Your Inner Fish” which discusses his work in tetrapod evolution and how it relates to human anatomy. This means we are comparing humans and species the public would call fish. If we go back to the common ancestor of modern humans and modern fish I would strongly suspect that a layperson would describe that common ancestor as a fish. If we used that to name the clade, then we humans belong to the fish clade. That’s the story Shubin is trying to tell.
What we name a clade is arbitrary. Scientifically, Sarcopterygii is a better than Fish as a name for the clade. However, “Your Inner Sarcopterygii” isn’t a very good book title.
The tree of life analogy works well here. In order to create a new genus, family, order, etc. you have to break that limb off of the current tree and reattach it further down the tree. With cladistics, the branches stay where they are.
I am actually taking the position of cladistics that only monophyletic groups are real taxonomic groups of life. So I still stand by that title.
To clarify, again, note that me saying that the cladistic usage is the only one that refers to a ‘real’ group, that doesn’t mean I think that is the only one we should use or the only one with utility. Sorry, at this point, I feel like I have to make this clarification every single time preemptively.
I don’t know. I think it’s rather interesting, but if you don’t want to continue that is fine by me.
Certainly. “Fish” is the name of a more inclusive clade that includes Actinopterygii and Chondrichthyes at least. And that’s probably what Shubin intended too.
I do not understand that sentence. Are you contrasting the Linnean hierarchy with the actual tree of life, so that, for example, detaching Class Aves from Class Reptilia implies removing Aves from Reptilia and turning the two into sister branches on some imagined Linnean tree? I don’t think that happens. The Linnean hierarchy doesn’t represent a tree of descent.
I was thinking more temporally. At one point in time you would have a single species. If the descendants of that single species were successful and diversified then what was once a single species would now comprise a new family or order. So at the beginning the species group would have been within another family or order, but over time they would be placed next to other families and orders that may actually contain their ancestors.
You are right, it doesn’t, but it is sometimes misunderstood as a tree of descent.
If you just replaced “real” with “monophyletic” or “cladistically consistent” or something of that flavor, there would be no debate. It would be more precise, and it wouldn’t embed the false claim that all other groupings are “not real.”
Why not just drop “real” and move to the more precise language?
Real and not real does bring in a lot of philosophical baggage. Would it be better to say that there are subjective and objective species groups?
That would probably defuse things. But isn’t “objective” more or less a synonym for “real”? Perhaps I shouldn’t have said that.
Since we have no need to consider what a Cambrian or Permian systematist would have thought, I don’t see the relevance here. Also, this isn’t about taxa; it’s about the rank assigned to a taxon, which is arbitrary. One could say that ranks are not real.
Let us hope to avoid that misunderstanding.
However, my argument is that only monophyletic groups are ‘real’, or ‘natural’ or ‘objective’ (whatever suits you) groups of life, while paraphyletic and polyphyletic are not. My intend is not to avoid a debate, as you may have noted. But then again, I am not saying that you nor anyone else is obligated to engage with me in this debate.
Oh, c’mon. You can’t suggest this right after saying that it is a false claim that all other groupings are “not real.” That’s not fair at all.
I do treat them as more-or-less synonyms, or rather definitionally that a ‘real’ group is a group that can be ‘objectively’ defined.
Those two are often linked together, but something can be real even if it is subjective. Emotions are real things, as an example.
OK, but is this relevant to taxa? Would you claim that paraphyletic groups are real even if they’re subjective?
“Real” leaves a lot to be desired. Is there a real category called “fish” that humans put species into? Yes. Even if the categorization is a subjective and arbitrary, the category still exists so it’s real. If we grouped sheep by being black and white those would be real categories even if we failed to arrange them by ancestry.
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I think it depends on how you look at it.
If you ask whether a person is “experiencing emotions” or not, then it is not subjective. But asking how would it feel to experience that emotion for yourself, that is subjective. If I am not mistaking, the latter is called ‘qualia’ in the philosophy concerning the mind.
Also, I second what @John_Harshman said. We don’t belong to the bacteria clade @vjtorley so the statements “we are fish” and “we are bacteria” are not equally justifiable.
OK. Let’s get more precise. According to one widely accepted proposal, eukaryotes are a clade within the superphylum Asgard, a group within the domain Archaea. Archaea are defined in Wikipedia as “a domain of single-celled organisms” that were initially classified as bacteria; however, the term “Archaebacteria” has now fallen out of use. My point still stands. Calling humans Archaea is fine by me, just as it’s perfectly fine to call them chordates. But calling us fish is as silly as calling us single-celled organisms.
Saying “we are fish” is no less justifiable than saying “we are mammals” or “we are animals” or “we are monkeys”.
The term “mammals,” in ordinary parlance, refers to warm-blooded vertebrates that feed their babies milk, including humans. On the folk view, what unites them is their anatomical similarities, as well as a fundamental similarity regarding their way of life. Happily, this folk category turns out to be monophyletic, so nobody can possibly object to the statement “Humans are mammals.” (By the way, the claim that William Jennings Bryan objected to this statement at the Scopes trial is a canard invented by H. L. Mencken - see here and here and finally, here.)
Re “We are monkeys”: evolutionary biologist Jerry Coyne doesn’t think so, judging from his family tree of primates in a post dated November 2, 2015. Humans are anthropoids; monkeys are a paraphyletic group. Coyne doesn’t appear to think we’re fish, either, judging from his remarks in the same post, where he declares that we “belong to the class Sarcoptrygii, which are descendants of early fish.”
John Harshman also made the following damaging admission in a comment on Jerry Coyne’s blog:
Oddly, though, there are plenty of biologists (not me) who would also say we aren’t apes. John Hawks is one, for example. And there are even some who would say we aren’t even descended from apes, including such prominent voices as Francisco Ayala. (None of this is about phylogeny; it’s about names. Still doesn’t make them right, though).
John Hawks’ 2012 essay, Humans aren’t monkeys. We aren’t apes, either is well worth reading. He concludes with the following observation:
We shouldn’t smuggle taxonomic principles into everyday language to make a political argument. That’s what “humans are apes” ultimately is – it’s an argument that we aren’t as great as we think we are. Whether humans are special or not should be derived from biology; I don’t think we need to make the argument by applying Orwellian coercion to the meanings of English words. Biologists control taxonomic terminology, and that’s where science should aim.
The statement “Humans are fish” is flawed, not because we are unrelated to fish as creationists falsely claim, but because our relationship to fish doesn’t define who we are. Ancestry isn’t ontologically fundamental; from a moral, social and political perspective, our ancestry is supremely unimportant. It’s what we can do here and now that counts. And that’s every bit as “real” as the fact of evolution.
Not in the least. “Fish” can be defined in several ways, according to taste and circumstances. There’s no similar room in defining “single-celled organisms”.
Why should we care what Jerry Coyne thinks? And this is a misinterpretation of that post anyway. He says nothing about monkeys and merely reproduces a figure he got from somewhere else and uses only for the purpose of defining “ape”, not “monkey”. Better you should cite Francisco Ayala, who wrote a whole book with the title Am I a Monkey and whose first chapter says “no”. But Ayala is mistaken, and so would Coyne have been if he had ever made such a claim.
Again you misunderstand what Coyne said. Of course Sarcopterygii are descendants of early fish. All extant fish are descdnants of early fish. But they’re still fish. That in fact is the basic rule of cladistic classification: once a fish, always a fish.
In what way is this a damaging admission? I merely admit that some biologists are wrong about some things. I would gladly admit it again, if you like. Hawks too is wrong. If you want to make an argument that he’s right, feel free to do so, and I’ll respond.
One could argue whether it’s unimportant from those perspectives, but it’s certainly important from a biological perspective, and why should we always ignore biology, even in ordinary speech?
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I was anticipating one might go there. We actually need to be more precise. What you are referring to is the research that indicates the original host cells at the origins of eukaryotes came from (asgard) archaea. However, you need to bear in mind that the endosymbionts that became the mitochondria originated from (alphaproteo)bacteria. The origins of eukaryotes wasn’t simply the result of evolutionary descend and divergence, but rather a combination of endosymbiosis and horizontal gene transfer. It’s also important to note that our “bacterial heritage” isn’t just the mitochondria. Our nuclear genome is full of genes that originated from bacteria (most of the genes are in fact bacterial), and our phospholipids contain ester bonded like bacteria, while that of archaea have ether bonds. It’s curious that bacterial genes are often involved in ‘operational processes’ such as in metabolism, while archaeal genes are involved in ‘informational’ processes; i.e. genetic replication, transcription and translation.
The chimeric and complex origins of eukaryotes is one example where cladistcs breaks down, so it isn’t really accurate (or at the very least a complete description) to say that eukaryotes are descended from archaea, bacteria, or prokaryotes.
No it’s not. Being “single celled” is a character state that in most cases is a plesiomorphy, and on other instances an apomorphy, since there are things that have “gone back” to being single celled, multiple times even (homoplasy). Cladistics doesn’t hold that character states cannot change along evolutionary lineages. Different character states are analyzed to determine synapomorphies (shared derived traits) and the clades are identified on these. So this isn’t a coherent objection against cladistics.
I wouldn’t say ‘nobody’. But I don’t see why this even matters on whether the statements are justifiable. This is basically an appeal to popularity.
I don’t care if he said that.
The common name for ‘sarcopterygii’ is ‘lobe-finned fish’. Also, due to the rules of cladistics, saying “descended from fish” is no different than saying “is a fish”.
I have read that blog post a while ago and it is still as bad as I remember. Especially that part that you quoted where he makes a bizarre appeal to motive claiming the statement “humans are apes” is ultimately political argument for why humans aren’t special. Like wow…while I do criticize human exceptionalism, the reason why I would say “humans are apes” is because that statement is as accurate as saying “chimps are apes”, not for the sake of refuting human-exceptionalism.
Nowhere does Hawks actually dispute the accuracy of what is actually meant by the statement “humans are apes”. He only argues over what words to use. He is basically admitting that humans are apes, but argues for using Latin or Greek derived words used by taxonomists. So he would say ‘humans are hominids/hominoids’ instead, but don’t communicate that in plain English. I don’t subscribe to that idea and I find it a rather silly suggestion, particularly when he says the following:
I don’t think I’m being old-fashioned, nor am I promoting the idea that humans aren’t part of the primate phylogeny. I’m only promoting the idea that we use taxonomy for its intended purpose, and not insist that English do the job instead. “Ape” is an English word. It is not a taxonomic term.
The logical implication of this is that you cannot object to someone on the grounds of taxonomy if they use English terms. If someone says that whales are fish, don’t take any issue with it. ‘Whale’ and ‘fish’ are English words, not taxonomic terms; and it is rather common for people to call whales fish in every day English. So we shouldn’t say they are wrong, otherwise it is imposing taxonomy on English. [Just before anyone points this out, yes I would say that whales are fish although not for the reason some people would say that. Here, I am using an example that you would accept on purpose.]
Even Hawkins himself doesn’t follow his own suggestion when he teaches his children that chimpanzees are not monkeys. His own arguments works equally well against that. ‘Chimpanzee’ and ‘monkey’ are English words. It’s common vernacular to say that chimps are monkeys. Colloquial languages have no problems with this.
The biggest issue with the idea that Hawkins promote is that folk taxonomy IS a form taxonomy, and it is not immune to correction as Hawkins has to admit himself whenever he wants to correct people by saying that chimps are not monkeys.
Who ever said otherwise?? I never said that being a fish has is important from all such perspectives. Similarly, I wouldn’t say that being mammals is important to me morally, socially or politically.
I am not even sure what you are even trying to say here. Like you have said you have no issue with the idea that humans are mammals. You wouldn’t say that the statement “humans are mammals” is flawed because our relationships with mammals doesn’t define who we are, right? Now it should be very easy for you to understand why this is similarly not a coherent objection against the statement “humans are fish”.
You should also note that English terms change meanings all the time as a result of various influences, some of them from biology. “Ape” in fact, once referred to tailless cercopithecid monkeys exclusively, e.g. “Barbary ape”. Then it was expanded to refer to gorillas and chimps too, and, under the influence of biology, stopped referring to any cercopithecids.
@vjtorley apparently take the currently popular sense of any word to be fixed for all time, a position decidedly at odds with the history of actual language.
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