The Classification of Eukaryotes

Describing Evolution

Cladistics

David Pilbeam wrote a neat essay in 2000, trying to assess the relative value of the different sorts of characters that can be used to assess relationships. At least in terms of hominoids (apes and humans), the molecular evidence looks most reliable, followed by soft-part characters, while bones and teeth are least reliable.

As Pilbeam says, "This presents something of a problem for us paleontologists."

However, molecular data is not available for fossils, except in a few cases, and they are all less than a million years old. Soft-part data for fossil organisms is only as good as the hard-part data hat allows one to identify the fossil, or to reconstruct its soft parts. So whether we like it or not, hard-part data -- from bones, teeth, shells, etc. -- is what we have to work with, and we do the best we can with it. [One could argue that Pilbeam presents too extreme an analysis; perhaps the paper could provide a basis for discussion.]

Reference: Pilbeam, D. 2000. Hominoid systematics: the soft evidence. Proceedings of the National Academy of Sciences 97: 10684-10686.

Last updated March 5, 2006.

Links checked September 30, 2005.