From: colby@bu-bio.bu.edu (Chris Colby)
Newsgroups: talk.origins
Subject: Re: biologic diversity since the Cambrian
Keywords: scientific creationism
Date: 14 Apr 92 22:50:32 GMT
Reply-To: colby@bu-bio.UUCP (Chris Colby)
Organization: animal -- coelomate -- deuterostome

In article <s700tINNcu2@matt.ksu.ksu.edu> jsanders@matt.ksu.ksu.edu (Justin M. Sanders) writes:
>In article <83702@bu.edu> colby@bu-bio.UUCP (Chris Colby) writes:
>>In article <1992Apr6.124012.1268@news.nd.edu> scharle@lukasiewicz.cc.nd.edu (Scharle) writes:
>>
>>>At least since Cambrian times (please correct me if I am 
>>>wrong here, this is just a layman's opinion) there has been no 
>>>overall increase in the complexity of life on earth.
>>
>>	I don't think there is really a consensus on this. Clearly
>>diversity changes with time both within and between lineages.
>>example, diversity (as measured by number of families) has gone
>>	Likewise, the taxonomic distribution of organisms inhabiting the
>>earth has changed numerous times. In order to determine if diversity
>>or complexity has increased, a yardstick for measuring it must be
>>developed. 

>Diversity is only indirectly related to complexity (the kind of complexity
>which might bear on a 2nd Law of Thermo argument). 

	Diversity or complexity as used in my and Tom Scharle's post
has nothing to do with the 2nd law of thermo. It would simply be a
measure of morphological diversity between/among lineages in the case
of diversity or [I don't know what] in the case of complexity. The
only thermodynamically interesting (O.K., I'm exaggerating) aspect
of evolution would be photosynthesis. It is through this process that
a local decrease in entropy is accomplished (at the expense of much
energy from the sun -- i.e. a net increase in entropy.) Water and
carbon dioxide are made into sugar, a useable form of energy to
organisms. From that point on, it doesn't matter if the energy is
used by a complex organism or a "simple" one -- energy simply flows
"downhill" -- from a more useful form to a less useful form.

>    As with many creationist arguments, the abuse of the 2nd Law of 
>Thermo dynamics stems in part from semantics.  They take advantage of
>the fact that complexity has slightly different meanings and that the
>definition of complexity which might be properly applied to the 2nd Law
>is not a very common or well known one.

	Right, complexity would have to mean something along the lines
of more useful energetic configuration of [whatever] if my grasp of
thermo is adequate (I had P-chem in college, but never a thermo course).
Biological diversity or complexity would not fall into this category as
more complex organisms (or more diverse lineages) are not less
energetically favored or any such thing. Complexity/diversity is
brought about by unequal reproductive rates of genetic variants (i.e.
natural selection). As energy flows downhill from useful forms (sugar)
to useless forms (heat), some of the organisms that make use  of the
energy as it degrades are better at reproducing them selves than others.

>-- 
>Justin M. Sanders         "I can trace my ancestry back to a primordial,
>Dept. of Physics            protoplasmal, atomic globule."
>Kansas State Univ.           --Poo-Bah, in _The_Mikado_, Act I

Chris Colby	email: colby@bu-bio.bu.edu
"And will our voices be heard/Or will they break like the wind"
-Spinal Tap