Newsgroups: sci.bio
Path: utzoo!utgpu!lamoran
From: lamoran@gpu.utcs.utoronto.ca (L.A. Moran)
Subject: Coelacanth and Evolution
Message-ID: <1991Jun18.200327.12235@gpu.utcs.utoronto.ca>
Organization: UTCS Public Access
Date: Tue, 18 Jun 1991 20:03:27 GMT


Boris Borcic said,

     "As for justifying my statement that there is a bias towards the 
      molecular view, *without* assuming knowledge of biology other than 
      what is according to you, it is logically sufficient to note that 
      biologists [TM Moran] mean "evolution of molecules of lifeforms" 
      when they say "evolution of lifeforms".

      Whether this bias is reasonable is all together a different question...

The word "bias" is insulting. To be accussed of bias is to be accussed of
holding an UNREASONABLE or IRRATIONAL prejudice. Thus, there is no such thing
as "reasonable bias".

When you accuse all biologists of bias you are stating that they have an 
opinion or concept that is irrational for one reason or another. It is quite
natural that I react to such a statement and it is acceptable for me to
question your authority to make such a statement. So far, you have not given
me any reason to accept your accusation. If you wish to explain why you
think that biologists are biased then now is the time.

Boris says,

     "I gather from your responses to the original poster and to me that 
      a bias is to you the difference of any view to the expert's view; 
      e.g. a pejorative someone who knows better is free to use on someone
      who knows less well. By this definition, the expert's view is of 
      course devoid of bias. The matter of biasses would moreover be
      completely extra-scientific since in a world where everybody shared
      "the" scientific view, there would be no biasses."

Let's review the history of this exchange. You said that lack of morphological
change is evidence that evolution has not occurred. I responded that evolution
can occur at the molecular level and that morphological change does not have 
to be evident. I pointed out that the scientific definition of evolution is a
molecular one. You responded by accusing all biologists of a bias towards a
molecular definition! No one accused YOU of bias!

I made a well-meaning attempt to educate you in an area with which I am very
familiar and you are not. You respond by claiming that you are right and I 
am biased. There doesn't seem to be any point in continuing. I'm sorry that
you react so negatively to criticism.

Boris Borcic said,

     "Molecular variation per se doesn't strike me as the only and 
      undisputable foundation for measuring an amount of evolution. Evolution
      is an ecological process as well as a molecular one, and it is not 
      obvious (to me, at least) that a measure of the evolution of a 
      particular organism/species by what is significant at the molecular
      level should be automatically congruent to a measure of the same by what 
      is significant at the ecological level."

I (Larry Moran) commented,

     "I don't understand what you mean by "ecological process". But, as I 
      stated above, you are free to create your own definition of evolution
      as long as you tell us about it. We, on the other hand, don't have to
      agree with you! Please tell us more about the Boris Borcic non-biologist
      definition of evolution."

and Boris replied,

     "Here I must question your good faith :-( since the paragraph you 
      cite was followed by two others you conveniently deleted and where 
      I made my meaning clear, or at least clearer."

I did not behave in bad faith. I read the following two paragraphs as well.
If you want to discuss your ideas about evolution then I would be happy to 
hear them but I honestly do not understand what you mean by stating that
evolution is an ecological process - especially when you contrast it with
molecular variation. If you do respond by clarifying then please state in
your next posting whether you want to engage in a scientific discussion of
your ideas or whether you would prefer not to hear from biologists.

I said,
 
   "My own personal favorite among organisms that exhibit some "primitive"
    characteristics is Pelomyxa palustris, a single-celled eukaryote that
    shares some of the characteristics of the first eukaryotes. These 
    characteristics are over one billion years old. Sorta puts coelacanths
    to shame doesn't it!"

Boris said,

   "I guess Peloxyma palustris is also easy to grow in the lab ?"

No, it is impossible to grow in the lab. The organism dies within a short time
of being removed from its normal environment. There are only a handful of 
different samples that have been described. (Is there a point that you were
trying to make?)

Boris goes on to say,

   "Look, I am no special fan of coelacanths or "living fossils". My own
    personal favorite among exceptional patterns of evolution is convergence,
    and my favorites among organisms that exhibit it are Hummingbirds and
    Sphingidae. Adults of these two very specialized and extraordinary families 
    - as compared to their respective phylogenetical neighbors - display
    a striking similarity in shape, size, locomotion, nutrition, and,
    to a limited extent, thermoregulation and migrating practice.

    The observation of a feeding Hummingbird and a feeding Sphinx, hovering 
    in static flight over some flower with their long buccal instrument 
    dipping in nectar, tells me these two groups have something particular
    in common.

    (And if you tell e.g. "you ignorant, they are also some bats", I'll say 
    "ok, add in the bats if you think they belong") 
 
    Now one is a bird and the other is an insect. What was their closest 
    common ancestor like ? How do their molecules compare ?

    If your model of evolution implies a state-space for species such that 
    common factors like the one between Sphinxes and Hummingbirds cannot be 
    evidenced, I'll say it is incomplete.

    If you tell me that such a model is the only one serious biologists would
    consider (which I do not believe), I will say that biologists are not true 
    to observation."

The common ancestor of chordates and arthropods probably lived about 700
million years ago. It was likely a seqmented worm-like creature but it could
have been unicellular. The DNA and protein sequences of birds and insects
confirm that they separated about his time. In other words they are fairly
closely related on an evolutionary scale.

Boris, in good faith, I do not understand your statments about "state-space"
and convergence. Do you see convergence as a major problem for biology?
If so please explain why. As far as I know the modern theory of evolution
would not have any trouble with the example that you quote.

-Larry Moran
