Evolution Discussion

Brian Foley brianf at med.uvm.edu
Tue Feb 15 16:34:28 EST 1994


wpainter at vnet.ibm.com wrote:
: I would like to start a discussion on Moleculare (DNA) evolution.  My first 
: topic is the current Bio-Soup theory.

: Since I am educated in Computer Science, and I am a layman in Molecular
: Chemistry, I would like to start with a question.

: What are the current estimates on the total number of species of plant and 
: animal life in the world today?
	You might just as well make up a number yourself, because there are
a number of unanswered problems to solve before one could even start to 
make and educated estimate:
	What is your definition of "species" going to be?  The criteria 
used to define mammalian species do not work for bacterial species. 
	How are you going to estimate the number of species of life forms 
that are not of interest to man?  Humans are mammals so we have a pretty 
good idea of the number of other mammals on earth, but we have really 
paid no attention to how many types of microorganisms might inhabit all 
the different ecosystems on earth.  There are known to be many "species" 
of bacteria that cannot yet be cultured in the lab.  Dr. David Ward at 
Montana State University has made some estimates of the number of 
bacterial species in one Yellowstone hot spring.  He used PCR to amplify 
rRNA from bacteria collected on a filter paper and found that there was 
far more variety than had been expected.


: What are the current estimates of the total number of species of plant and 
: animal life that have existed on the Earth since its formation and the first 
: appearance of life 3.5 billion years ago?
	Multiply the above problems by a factor of 100 or so...

: If someone can answer these questions for me then I have some good discussion
: points on evolution that I would like to make.
	Would it be possible to start the discussion without the 
answers?  

--
********************************************************************
*  Brian Foley               *     If we knew what we were doing   *
*  Molecular Genetics Dept.  *     it wouldn't be called research  *
*  University of Vermont     *                                     *
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