Humans, Apes, Monkeys, and Monophyletic Taxa

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Carl Zimmer (one of the best general audience science writers) has a post on his blog on how the human immune system differs from that of other primates and even other apes. It's a good example of why biomedical researchers need to understand evolutionary biology (and why dumb shits like this should not be trusted with the lives of their patients). That said, I've got a little nit to pick with Carl. He wrote:

The scientists decided to compare human T cells directly to those of apes. It turns out that unlike humans apes produce a lot of Siglecs on their T cells.

C'mon, Carl, you know better than that. What am I bothered by? Well, as I've written before, humans are apes. What Zimmer wrote is akin to saying that Europeans are different from humans because Europeans have white skin. Sounds kinda stupid doesn't it? Europeans are humans. What can I say? I'm a stickler for monophyly.

And while we're at it, let's stop using the paraphyletic taxon monkeys. There are old world monkeys and new world monkeys. We apes are just one type of old world monkey. Oh, and we're all fish as well. Don't mess with the cladist.

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I'll need to read the paper, but the T-cell differences may explain why we die from HIV but SIV don't kill chimps.

And the old gradistic/cladistic argument. Many paleoanthropologists like to say that "well technically we're apes, but not really."

And as for monkeys being paraphyletic, not necessarily. We're pretty sure that all anthropoids arose from a common tarsier-like ancestor. The term 'monkey' only becomes paraphyletic if we imply that platyrrhine and catarrhine monkeys should be grouped to the exclusion of fossil anthropoid taxa.

wanted to add that I like the fact that you pointed out that we are apes. And that apes are old world monkeys. I think a lot of bioanthropologists forget that.

yes, humans are apes
apes are old-world monkeys (we are old-world monkeys)
old-world monkeys are...monkeys (we are monkeys)
monkeys are primates (we are primates)
primates are mammals (we are mammals)
mammals are amniotes (we are amniotes)
amniotes are tetrapods (we are tetrapods)
tetrapods are rhipidistian crossopterygians (we are RCs)
RCs are osteichthians (we are...)
etc. vertebrates, craniates, chordates, deuterostomes, bilaterians, triploblasts, animals, eukaryotes. etc.

Maybe you're right--Carl should have compared humans to "other apes" instead of just "apes." I'm sure he would have written "humans vs. other primates," for example, or "humans vs. other vertebrates."
But it just seems weird to say "humans vs. other monkeys" or "humans vs. other fishes." Why?
Because vernacular English organism categories are not cladistic, that's all. If someone sez "monkeys" it's understood that she means "primates other than apes and lemurs" or something like that, "Fishes" means "non-tetrapod vertebrates." These are paraphyletic. So what? Communication is usually clear regardless. We have Latinate multisyllabics to label the clades unambiguously. People don't generally know or use these scientific epithets--they use (around here) English. And in vernacular English, "ape" connotes "other than humans."
I think this is no big deal, though I'm as cladistically oriented as the next guy.

I know it is a trivial point. Disregard for monophyly is one of the two stupid things that bother me (the other being putting meaning into higher order taxonomic levels or oversplitting/lumping), and I'll point it out whenever I see it.

I don't think the point is all that trivial, especially when it comes to discussing the evolutionary relationships of humans. We put ourselves on too high a pedestal, which has the effect of closing our eyes to the evolutionary origins of various facets of our behaviors (so we call things 'unique' that really aren't).

and the use of exclusionary language, though subtle, will only further that divide.

*shrug* maybe it's cuz I was a comp lit nerd, but words and implied tone are very important IMO.

However, monkeys are right out

Not if you want to define monkeys by common descent. As CCP once put it:

yes, humans are apes
apes are old-world monkeys (we are old-world monkeys)
old-world monkeys are...monkeys (we are monkeys)
monkeys are primates (we are primates)
primates are mammals (we are mammals)
mammals are amniotes (we are amniotes)
amniotes are tetrapods (we are tetrapods)
tetrapods are rhipidistian crossopterygians (we are RCs)
RCs are osteichthians (we are...)
etc. vertebrates, craniates, chordates, deuterostomes, bilaterians, triploblasts, animals, eukaryotes. etc.

If you don't want to think of humans as descended from monkeys, you've
got to fight the cladists (e.g. , RPM) for your right to paraphyletic
taxons.

What do you gain by insisting humans are not monkeys? Escape from the
phraseology creationists use to ridicule evolution?

What do you lose by insisting humans are not monkeys? You lose the the
opportunity to define a category of animals by common descent. You
lose the opportunity to remind people that humans are not 'special' -
we're animals like any other.

Human mitochondrial DNA (mtDNA)/Y-chromosome phylogeography shows very strongly that homo sapiens came "out of Africa".

But such explanation is generally too totalistic. New to paleo-archaeological debates, I see how the field is unnecessarily diminished by the historical division between "out of Africa" and "regionalist" camps, in the Homo floresiensis discussion for example.

Both sides tend to illogically totalise, fail to mention or see that, while homo sapiens and the hominid genus almost certainly came "out of Africa", Homo Erectus probably came out of Asia (Kohn 2006). Some homo erectus ancestors and other hominids may also have come "out of Asia".

Kohn writes: "homo erectus materialised almost simultaneously in Africa, east Asia and a point in between . . . and that the dates do not rule out the possibility that homo erectus evolved in Asia."

This difference between homo erectus, homo sapiens centres of endemism is not only true, it is also very telling, has implications. As I explain in (paper 5 page 6 of) my ebook at www.nodrift.com/vol_5/5.1.pdf :

"SEXUAL SELECTION THUS MOST IMPORTANT FOR HOMO SAPIENS
. . . evolutionary considerations AND homo sapiens evolving in AA Africa, coming "Out of [AA] Africa", not "Out of [IR] Asia", page 5, imply a corollary:

Conventions are very much a product of sexual selection. Sexual selection has thus evidently been more important than natural selection in evolution of homo sapiens, in contrast to evolution of homo erectus, where natural selection may have been more important than sexual selection."

REFERENCE: KOHN M. 2006. New Scientist. 2558, 1 July 2006, p35, p39.

i DONT BELiEVE THAT HUMANS CAME FROM APES. BECAUSE WHY DiDNT THE PRESENT APES BECAME HUMAN?.WHY DOESN'T THE PRESENT HUMAN BECAME APES?.I'M STILL WONDERING WHY DO THEY THINK THAT HUMANS CAME FROM MONKEYS..

xx

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At the risk of responding to a spoof -

i DONT BELiEVE THAT HUMANS CAME FROM APES. BECAUSE WHY DiDNT THE PRESENT APES BECAME HUMAN?

If many Americans are descended from Europeans, why haven't all Europeans become American?

Why should they? They are doing a perfectly good job at being (other) apes or Europeans, depending on which question you are answering. At least, the other apes were until we started destroying their habitat.

By Richard Simons (not verified) on 14 Jan 2008 #permalink