the more advanced species

Bernard Heymann bheymann at bragg.bio.purdue.edu
Sat Feb 19 13:55:20 EST 1994


In article <1994Feb19.014318.16024 at spartan.ac.BrockU.CA>,
wcade at spartan.ac.BrockU.CA (W. H. Cade) wrote:

> Antonio Guia (guia at CC.UManitoba.CA) wrote:
> 
> : It has always been my belief that ALL species continue to evolve through
> : the course of time, such that the paramecium is just as advanced as a
> : human in terms of evolutionary adaptation to its environment.  The only
> : measure that we have of the fitness of a species is, after all, how well
> : it deals with its environment.  This would mean that man did not come from
> : ape, and ape did not come from monkey, etc on down the line, but instead
> : man and ape both came from a common, more primitive ancestor, which shared
> : enough traits with both man and ape to have been the source of the lineage.
> 
> : With this in mind, when I see information in texts, and when I hear
> : conversations stating that man is more advanced than fish, or plants, or
> : even the paramecium, I usually take it to mean the complexity of the
> : organism, rather than how advanced it is.   
> 
> : With this prelude, is it correct to say that man is the more advanced, or
> : among the more advanced species on the planet?    I have not done any
> : comparative genetics studies, so I don't know much about how many genes
> : other species have, but I do know that the human genome contains many
> : repetitions of the same or similar genes, so I guess that would detract
> : somewhat from the complexity.  
> 
> : Comments and discussion are invited.  I see this kind of belief
> : everywhere, and would like to know if I'm somewhere out in left field in
> : believing that humans are not necessarily the most advanced species on the
> : planet.
> 
> : -tg
> 
> I think advanced is a poor term and successful is more appropriate to
> describe species.  Advanced can only apply to particular
> environments/habitats.  Mammals are more advanced in thermoregulation and
> and thus more widely distributed than some vert groups.  I agree with the
> beginning of tg's post.
> 
> Success of species can be measured in various ways, but two favorites are
> biomass and more importantly, number of species.  Number of species is
> probably correlated with longevity over evolutionary time.  The insects
> are, of course, the most successful by most measures. There are also lots
> of nematodes, but species diversity is much lower than insects.  After
> all, it their plant (the ones with 6 legs)
> 
> whc

Although I'm not working in the field of evolution, I thought that the
terms advanced and primitive are well understood in the context of the
comparison of organisms. Organisms exhibit both primitive and advanced
traits. An advanced trait indicates specialization or adaptation of the
organism to fit into a specific niche, which at the same time may make it
impossible for the organism to survive in other niches. Thus, primitive
traits allow an organism to survive in avariety of niches, but maybe not as
competitively as the more adapted organims in those niches. My point is
that to describe an organism as advanced or primitive, relates to its level
of specialization.

An example: A human's hand has five fingers with an opposing thumb giving
it good grasping ability and is definitely an advanced feature as compared
to say, a fish's fin. But, that same hand is much less specialized than a
horse's hoof, which has lost some digits. These arguments can similarly be
made for the features found in the genomes of the organisms, and are not at
all less ambiguous than for the more readily observed, macroscopic traits. 

On another point, complexity does not necessarily equate to specialization,
since many parasites (which show high specialization) get rid of systems
which they don't need any more and are supplied by the host, in effect
making them simpler organisms!

To return to the whole organism. I think the original poster's question was
an effort to either say Man is the most advanced organism (which obviously
cannot be true in the sense of evolutionary advancement as I explained
above), or to say Man is equal to all the other organisms in its
evolutionary success (which is also untrue since quite a few organisms are
going extinct).

It seems we always seek simple answers to apparently simple questions, then
just to realize that life, the universe and everything cannot be explained
in simple terms. My ultimate view is that being a fairly advanced organism
does not necessarily translate into a successful or "good" (whatever that
means) organism. Thus, although the question is interesting, it is a
philosophical one rather than a scientific one, and I don't think there
exists any unambiguous answer.

-- 
Bernard Heymann
bheymann at bragg.bio.purdue.edu



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