Ergaster

Guess what--it's out of date. At least, it's weird. I've never seen "Panidae" in any reference, even out-of-date ones. I wonder where the author got it from.

Doubting Didymus

Thats the paraphyletic group I was talking about earlier, not at the genus, but the family level.

Of course, taxonomic charts change labels like the rest of us change our pants: once in every year or so.

theyeti

I was looking at this page. The chart on the left has monophyletic groups with subfamily Homininae containing chimps and humans. As far as I'm concerned, that chart doesn't need any fixing.

There's an alternative taxonomy on the right showing humans, chimps, and gorillas in the same subtribe, the Hominina, which does not distinguish any relationship between the three. Neither classification scheme is any more "correct" than the other; both use only monophyletic groups. The difference is that the chart on the left is more informative, but at the same time it employs more taxonomic levels. (The one on the right has those taxonomic levels listed, but a few are superfluous.) And that's the whole problem. You can have as many taxonomic levels as you have species, both extant and extinct, which can make for a real confusing mess. So at some point you have to sacrifice information for brevity. The name of the game is (or at least should be) communication. It's more of an art than a science.

theyeti

MrDarwin

Pretty darn useful, otherwise they wouldn't have gotten as far as they have. For better or for worse, our species is hard-wired to put labels (names) on things and concepts. Try slipping a phylogenetic tree into a verbal conversation sometime!

theyeti

They can be verbally or alphabetically communicated.

added in edit: Mr D. beat me to it.

Seriously, without taxonomic labels, you would have to reproduce an entire phylogenetic tree, with every single species labeled, everytime you wanted to talk about a particular derived character which belonged to a bunch of animals. All that trouble instead of just saying "mammals".

The usefulness of certain labels is also reinforced by the fact that there's lots of morphological gaps between certain groups, thanks to extinction. The mammals have a hundred or more easily recognized morphological synapomorphies and untold thousands of molecular synapomorphies. This might not be the case if the therapsids and other reptile-like mammals had not gone extinct. But as it is, it's extremely useful to talk about "mammals", as a group, because everyone recognizes certain key features that make them different from other vertebrates. (And there's another one -- the vertebrates.)

theyeti

Nic Tamzek

Traditional taxonomy also has a distinct problem with intermediates: e.g., let's say *for the sake of argument* that we agree that:

(1) Modern Pan and modern Homo belong in separate genera

(2) The common ancestor of both pretty much looked like Pan, enough that if it were alive today, we would put it in Pan.

What should we call this common ancestor? Pan, Homo, or a new genus?

I'm not sure that there is any good answer. Any way you do it, you have one genus giving rise to another, which contradicts the statements given by many in the thread along the lines that "a descendent stays within its taxonomic grouping".

Here is one solution that I might choose if I were Taxonomic Dictator:

1) The primitives of classification are only:

(a) species (I know this is messy, with various criteria, but that's life)

(b) monophyletic groupings of species (given names but without the traditional level-specific conventions of families, genera, etc.)


2) Complete traditional taxonomic ranks shall only be assigned to modern, extant organisms. There are way too many levels to the hierarchy of (1b) to assign each level a name (family, subfamily, supergenus, etc.), so they shall be assigned basically based on convenient/conventional monophyletic groupings above.


3) Extinct organisms will be classified and named according to 1a and 1b, but will not necessarily be assigned all of the traditional taxonomic ranks. E.g., a primitive cambrian chordate will be assigned to Phylum Chordata, and probably have its own subphylum as it's probably not on the direct line of descent to modern chordates; but beyond that no traditional classification is necessary.

What this would do is make the traditional taxonomic hierarchy reflect what it should reflect, namely, rough time since divergence. A cambrian chordates species shouldn't be given a family assignment, since modern chordate families didn't even exist then.

This would eliminate notions like "transitions between classes", "transitions between families", etc., that mess up our desire for our classifications to reflect monophyly. It would also make clearer the fact that the perceived large differences between animal phyla is an artifact of our present-day classification system more than a reflection of reality.

Anyhow, that's what I'd do if I were Taxonomic Dictator.

nic

pangloss

http://tolweb.org/tree?group=Hominid...oup=Catarrhini

pangloss

Nor I...

Must have been conoted by some media seeking paleoanthropologist...

pangloss

I just thought the suggestion that they were seeking media attention was rather uncalled for. That is the sort of thing I have come to expect some the anti crowd.Hence the proposal.]

MrDarwin

I think you're right, and I apologize--I made the same mistake I have cautioned other against, that of confusing the reporting by media with the actual conclusions of the authors. By definition, press releases are seeking media attention, and tend to emphasize (sometimes even misleadingly or even erroneously) the more unusual, counterintuitive, or sensational conclusions of a paper. (And it's a sad situation for scientists that they need to publicize their research in this way at all.)

Now, for my benefit, and for the benefit of others who don't have access to these papers, can you please summarize the proposal you're referring to?