Mr. Jack,
I am forced to respectably disagree with you on what morphological characteristics quantify differences between species and/or genera (not genii, plural of genius not genus). As an invertebrate zoologist with a great interest in human evolution I have always been skeptical of the differences perceived between fossil and extant members of the Hominidae, Homininae in particular.
I think it is very difficult to objectively look at differences in things that resemble ourselves. I think the study of human evolution has been clouded by this difficulty. In the pop-sci realm it has not better been illustrated than in the book Lucy The beginnings of humankind by Johanson and Edey. In their chapter 13 they discuss the analysis of what the fossils may be. The possibilities they explore are genus Homo, genus Australopithecus, or ‘something else’.The analysis concludes that the fossils (Lucy and the others representing Austrlopithecus afarensis) are australopithecines. Where I take exception is that the genus Pan was never considered (while they repeatedly made comparisons to this genus) as an alternate possibility.
I wish I had better photos but I want to illustrate the difference between accepted congenerics in crustacean biology:
and
The first is less than 50 mm across the carapace the second is commonly 150 mm and above. Both are in the same genus and this is supported by abundant morphological data including larval development. I would argue that the difference between a dungeness crab and a dwarf cancer crab are orders of magnitude more than between a human and a chimpanzee. The numbers of invert congenerics that differ more than that would stagger the imagination.
This message has been edited by Lithodid-Man, 09-03-2005 04:09 AM
This message has been edited by Lithodid-Man, 09-03-2005 04:25 AM