Coragyps

Linnaeus originally named the chimp Homo troglodytes - why it was changed to Pan I don't know. But it was probably pressure from fundies.
Link.

MrDarwin

Not that I want to defend the arbitrary assignment of new ranks and the arbitrary assignment of new names to every fossils, but precisely what has been "standardized", and by whom? Did somebody decide that if two species differ genetically by x percent, they must be classified in the same genus, but if they differ by x + y percent, they must be classified in different genera? So what are x and y?

pangloss

So I see you have not actually read any of Goodman's work on this topic.

It has nothing to do with %differences or similarities. It has to do with estimated times of divergence. The % similarities mentioned are just a further justification for the proposal.

Of course, doesn't "somebody" have to decide things once in a while?

pangloss

So, to paraphrase the conservative types, I guess we should go with the oldest name....

Ergaster

You're right--that probably would be the better way to put it. Never does seem to catch on, though.


Oooo nasty.

I dunno about "arbitrarily assigning ranks"--I don't see anything "arbitrary" about it, just an attempt to compromise between a meaningful taxonomy based phylogeny, but using a system which was not originally meant to reflect phylogeny but has the advantage of familiarity.

I will, however, concede that there has been a regrettable spate of "species-naming" in the past few years, with these new finds of early Homo (i.e. "Homo georgicus" and "Homo cepranensis", to name a couple). One hopes that lessons of the past have been learned, and that most of these things will find their proper place eventually ("Homo georgicus" has already been thrown into doubt).

MrDarwin

There's another element of compromise: fossils (and sometimes other kinds of specimens) are sometimes not good enough to decisively place in one known species or another, or even one genus or another. In addition, species are variable and a particular specimen may fall at one extreme, or even outside of, that range of variation. Naming a new species can be a statement of confidence (I have something new) or it can be a statement of ignorance (I have something I can't confidently assign to any known species, but it's significant so I'll give it a new name). Hopefully most taxonomists use it as the former rather than the latter! But species concepts are hypotheses that can be, and sometimes are, falsified.

pangloss

Yeah. Not too many people like to have to change their minds.

MrDarwin

I have, although it wasn't recently and I have to confess I haven't committed them to memory. In the meantime, I'm waiting to read the article currently under discussion, which I have not yet been able to read. All I have to go on is what is in the press release and the articles written from it which may very well be misleading or sensationalized, so I anxiously await being disabused of any misinterpretations of the conclusions of the study. I also make no claims to being any kind of expert (or even particularly knowledgeable) about this particular area, but I do know a thing or two about taxonomy, nomenclature, and even a little bit about cladistics.

But estimated times of divergence are not typically used as criteria for combining or separating species into genera, any more than are percentage of genetic divergence.

Sure, but if they do, I hope they provide some good justification!

My point is, this study may be confirming something, but it's something that nobody is arguing with: that chimpanzees and humans are each other's closest living relatives. It's the leap from that to combining the two into a single genus that I'm taking issue with. Does Goodman make the leap convincing? Sure, I'll have to read the paper itself to judge that.

Doubting Didymus

It seems that the general line is that taxonomic labels are arbitrary, but we keep them around because they are useful.

How useful are they, really? What can they do that a nice accurate phylogenetic tree can't?

Grumpy

I don't see how this is possible, unless this chart is out of date (which is always possible). Since it puts humans and chimps/gorillas in two separate families, no single subfamily could unite chimps & humans.

Shouldn't we straighten out what the current classification is, before we change it?