In article <1992Jun25.124005.21577 at hellgate.utah.edu> tolman%asylum.cs.utah.edu at cs.utah.edu (Kenneth Tolman) writes:
>>>> I will contend here that evolution IS associated with progress. Do you
>>>agree?
>>I suspect that evolution was equated with progress during its early
>ideological formation. Then the scientists realized this was too
>simplistic, and have been trying to swing the pendulum back the other way.
>However, the life forms around today certainly appear more complex than
>the original fossils that have been found, and certainly correspond to
>my intuitive notion of "progress". That is why I am interested in discussing
>this, to see what comes out of it.
>>>Occupation of a "larger" enviornmental niche could be considered one
>>_aspect_ of progress, but even this criteria is very problematic. For
>>one thing, I believe that studies of # of enviornmental niches occupied
>>versus time show that this index actually decreases rather dramatically.
>>There is a general pattern of life form diversification followed by
>>extinction of most of the branches.
>>Sure. Lets for a moment define "progress" as the sum total of all
>functionality exhibited by all species. (yes, a slippery eel) Certainly
>at many points during the evolutionary trail this "progress" has been
>backwards- probably due to environmental stress. But in the long run
>this functionality has exploded upwards. Especially if you consider the
>technological capabilites to be expanded functionality (which I do).
>Many important functionalities (warm blood, live birth, etc) end up
>slipping through the catastrophes...
>>>>Addition of mutation does not imply addition of functionality. For instance,
>>it may be advantageous for a life form to strip down its functionality and
>>thus devote more energy to its remaining functions. (You may be familiar
>>with computer programs which are overly general, and thus much slower than
>>a more finely tuned program.)
>>True, good point. However, a computer program which could switch from one
>set of commands to another on environmental change would be more powerful
>than one that could not.
>Some current examples of exactly these traits are the various forms of
intra-cellular parasites both prokaryotic and eukaryotic. They range from
obligate intra-cellular parasites such as Rickettsia sp., Ehrlichia sp., and
Coxiella sp. which have no free living portion of their life cycle and have
largely lost many synthetic pathways, to partially free living species
such as Legionella and Rochilemia, to opportunistic, normally free living
species such as Escherichia, Shigella, Vibrio, etc which have complete
biosynthetic pathways that can be turned on and off as needed depending on
the local envrironment. In all cases, these species exhibit "progress"
compared to their presumed ancestral forms since they share many presumed
"modern" characteristics.
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