--- Dave Gary <Dave.Gary@m.cc.utah.edu> wrote:
Actually, different body plans are represented by the phyla. There are, approximately, 37 phyla, therefore, there are 37 different body plans. This is the definition of phyla. I don't know where you got your information about 5 different body plans. Again, read James W. Valentine's "On the Origin of Phyla". His material will really get you thinking.
correctly pointing out factual errors in -
On Aug 28, 2005, at 7:33 PM, Canopus56 wrote: <snip>
The pre-Cambrian era is unique in evolutionary history in that nine or so novel new body plans evolved in mutli-celluar organisms in a relatively
short period of geologic time. Of the nine original body plans, only five survive today. No new novel body plans have evolved in the subsequent 560 million years.
Thanks Gary, that'll teach me to write on a Sunday afternoon from memory from Stephen Gould's 1989 _It's Wonderful Life_. I believe the correct statement is there are about 35 phyla (or 35-39 depending on who's counting), but in the pre-Cambrian there were about 50 phyla. The paradox is that so many phyla evolved in a short-period of time and then the diversity of phyla decreased. Since 1989, further investigation of Gould's interpretation of the pre-Cambian has been rejected and some of the fossils he interpreted as unique phyla have been reinterperted within existing phyla, e.g. Hallucigenia. Gary, thanks for keeping on me on my toes. It's a complicated question and misstatments of fact do not help. The factual mistake was not central to the issues regarding ID that I was discussing. In reviewing the the remaining assertions, they look okay to me. Let me know if that's not the case. - Canopus56(Kurt) P.S. - Thanks for the reference to "On the Origin of Phyla". I've added it to my Amazon wish list and used book search list. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com