[net.origins] Chairs and Chromosomes

dubois@uwmacc.UUCP (Paul DuBois) (04/29/85)

> In article <330@iham1.UUCP> rck@iham1.UUCP writes:
>> 6.  No known mutation has ever produced a form of life  having
>>     both  greater  complexity and greater viability [a,b] than
>>     any of its ancestors [c-f].

> [Mike Huybensz]
> Single mutations seldom would cause a new species to develop.  However...
> Autopolyploidy in plants is a standard trick of plant breeders to
> develop more vigorous plants by doubling or tripling their chromosome
> numbers.  Several species of plants are believed to have arisen
> naturally by this method.  I'd say that more chromosomes satisfies the
> greater complexity clause.

I'm a little surprised that you didn't say they satisfy the greater
viability clause.  That is more obviously true.

For complexity, I'd say number of chromosomes is meaningless.  There
is no relationship between chromosome count and complexity.

Man has 46.
Chrysanthemums: 18 - 198
Crustacea have from 8 to 208
Arachnids have from 6 to 84
Birds: 12-80
Insects: 5-380
The Radiolaria protozoa have over 800 chromosomes.  Are they therefore
more complex than any living organism descended from them? (Whatever
that might be...)

Chrysanthemums vary from 18 to 198 chromosomes.  Which one is most
complex?  Are they any different?

Salamanders have about half as many chromosomes as us, but twenty times
as much DNA.  One could say "I'd say that more DNA satisfies the
greater complexity clause."  How many and which parameters do you want
to consider?

>>     a)  ''Do we, therefore, ever see mutations going about the
>>         business  of producing new structures for selection to
>>         work on? No  nascent  organ  has  ever  been  observed
>>         emerging,  though  their origin in pre-functional form
>>         is  basic  to  evolutionary  theory.  Some  should  be
>>         visible  today,  occurring  in  organisms  at  various
>>         stages up to integration of a functional  new  system,
>>         but we don't see them: there is no sign at all of this
>>         kind  of  radical  novelty.  Neither  observation  nor
>>         controlled  experiment  has  shown  natural  selection
>>         manipulating mutations so as to produce  a  new  gene,
>>         hormone,  enzyme  system  or organ.'' [Michael Pitman,
>>         ADAM AND EVOLUTION (London: Rider, 1984), pp. 67-68.]

> Duplicated chromosomes would count as new structures, since each copy is
> then free to mutate in different directions.

So if I make a chair, and then I make another one, I have a new kind of
furniture - a new structure by duplication?  Come on.  Yes, the
chromosomes are free to mutate, but that in itself is no demonstration
of anything, except that they mutate.  It does not demonstrate, e.g.,
that any new structure *does* arise.

> There are quite a few candidates for nascent organs (assuming you are
> referring to things we can see today, rather than "evolution in one
> year right under my nose".)  Two examples I'm well familiar with are
> the development of claws in the family Dryinidae (some wasps parasitic
> on Homoptera) from the first tarsal segment, and the development of
> claws from a spur of the femur of mites parasitic in the gills of
> Hermit Crabs (Ewingidae, recently placed in the family Glycyphagidae.)

Ok.  You might have something here.  Please post some references.

-- 
                                                                    |
Paul DuBois	{allegra,ihnp4,seismo}!uwvax!uwmacc!dubois        --+--
                                                                    |
"There are two sides to every argument, until you take one."        |

hua@cmu-cs-edu1.ARPA (Ernest Hua) (05/02/85)

___________________________________________________________________________

> From: dubois@uwmacc.UUCP (Paul DuBois)
> > In article <330@iham1.UUCP> rck@iham1.UUCP writes:
> >> 6.  No known mutation has ever produced a form of life  having
> >>     both  greater  complexity and greater viability [a,b] than
> >>     any of its ancestors [c-f].
> > [Mike Huybensz]
> > Single mutations seldom would cause a new species to develop.  However...
> > Autopolyploidy in plants is a standard trick of plant breeders to
> > develop more vigorous plants by doubling or tripling their chromosome
> > numbers.  Several species of plants are believed to have arisen
> > naturally by this method.  I'd say that more chromosomes satisfies the
> > greater complexity clause.
> I'm a little surprised that you didn't say they satisfy the greater
> viability clause.  That is more obviously true.
> 
> For complexity, I'd say number of chromosomes is meaningless.  There
> is no relationship between chromosome count and complexity.
>
> Man has 46.
> Chrysanthemums: 18 - 198
> Crustacea have from 8 to 208
> Arachnids have from 6 to 84
> Birds: 12-80
> Insects: 5-380
> The Radiolaria protozoa have over 800 chromosomes.  Are they therefore
> more complex than any living organism descended from them? (Whatever
> that might be...)
>
> Chrysanthemums vary from 18 to 198 chromosomes.  Which one is most
> complex?  Are they any different?
>
> Salamanders have about half as many chromosomes as us, but twenty times
> as much DNA.  One could say "I'd say that more DNA satisfies the
> greater complexity clause."  How many and which parameters do you want
> to consider?

In some cases, I guess it might be legitimate to say so.  I would
write off "complexity" as a highly subjective term, and therefore,
useless.

> >> { a segment from rck's list of "evidences for creationism". }
> 
> > Duplicated chromosomes would count as new structures, since each copy is
> > then free to mutate in different directions.
> 
> So if I make a chair, and then I make another one, I have a new kind of
> furniture - a new structure by duplication?  Come on.  Yes, the
> chromosomes are free to mutate, but that in itself is no demonstration
> of anything, except that they mutate.  It does not demonstrate, e.g.,
> that any new structure *does* arise.

Simple duplication is not the same as different structures.  However,
as indicated by the original paragraph, this is a step in the right
direction.

> > There are quite a few candidates for nascent organs (assuming you are
> > referring to things we can see today, rather than "evolution in one
> > year right under my nose".)  Two examples I'm well familiar with are
> > the development of claws in the family Dryinidae (some wasps parasitic
> > on Homoptera) from the first tarsal segment, and the development of
> > claws from a spur of the femur of mites parasitic in the gills of
> > Hermit Crabs (Ewingidae, recently placed in the family Glycyphagidae.)
> 
> Ok.  You might have something here.  Please post some references.

Before he does, please specify the criteria under which you will accept
a developing/half/semi/pseudo organ.  Remember, an organ does not have
to serve the same purpose which under "development", if you can consider
any organ as "fully" developed.  There is no stated or implied "destiny"
of evolution of organisms, and certainly not of organs.  When creation-
ists say that an organ is half-developed, they imply that there must be
some destination for the transformations.  Theories of evolution does
NOT provide for any such destinies.  Basically speaking, the hair on
your head may be intermediates between its previous form and spikes.  It
may change to something else soon.
___________________________________________________________________________

Live long and prosper.
Keebler { hua@cmu-cs-gandalf.arpa }

mrh@cybvax0.UUCP (Mike Huybensz) (05/09/85)

In article <1005@uwmacc.UUCP> dubois@uwmacc.UUCP (Paul DuBois) writes:
> > In article <330@iham1.UUCP> rck@iham1.UUCP writes:
> >> 6.  No known mutation has ever produced a form of life  having
> >>     both  greater  complexity and greater viability [a,b] than
> >>     any of its ancestors [c-f].
> 
> > [Mike Huybensz]
> > Autopolyploidy in plants is a standard trick of plant breeders to
> > develop more vigorous plants by doubling or tripling their chromosome
> > numbers...  I'd say that more chromosomes satisfies the
> > greater complexity clause.
> 
> I'm a little surprised that you didn't say they satisfy the greater
> viability clause.  That is more obviously true.

The problem is that neither complexity or viability are defined above.
Vigor isn't the same as viability: the more vigorous mountain goat may
tend to leap to its death more often.  The more vigorous plant may not
use its resources with the restraint necessary to optimize its
reproductive success.

> For complexity, I'd say number of chromosomes is meaningless.  There
> is no relationship between chromosome count and complexity.

In organisms where chromosomes are comparable, it can make sense to
say one with extra chromosomes is more complex.  But we really need to
define "complex".

> Man has 46.
> Chrysanthemums: 18 - 198
> Crustacea have from 8 to 208
> Arachnids have from 6 to 84
> Birds: 12-80
> Insects: 5-380
> The Radiolaria protozoa have over 800 chromosomes.  Are they therefore
> more complex than any living organism descended from them? (Whatever
> that might be...)

Here we have an ideal example of comparing apples and oranges.  :-)
I'm sure we can construct many standards of complexity where man ranks
fairly low.  Our usual anthropocentric standard emphasizes one hypertrophied
organ that we posess.  But our genome might contain less information than
that of some of the organisms you list.

> Chrysanthemums vary from 18 to 198 chromosomes.  Which one is most
> complex?  Are they any different?

Mums are another classic example of polyploidy.  The many chromosomed
ones might be more complex by the standard of having more alleles
represented in their genomes.

> Salamanders have about half as many chromosomes as us, but twenty times
> as much DNA.  One could say "I'd say that more DNA satisfies the
> greater complexity clause."  How many and which parameters do you want
> to consider?

I didn't choose the measure "complexity".  Some creationist did.  Let him
make a choice, and we'll try to find some examples to fit it specifically.

> > Duplicated chromosomes would count as new structures, since each copy is
> > then free to mutate in different directions.
> 
> So if I make a chair, and then I make another one, I have a new kind of
> furniture - a new structure by duplication?  Come on.  Yes, the
> chromosomes are free to mutate, but that in itself is no demonstration
> of anything, except that they mutate.  It does not demonstrate, e.g.,
> that any new structure *does* arise.

Allow me to bend your analogy to a shape more like what I'm thinking.
Assume you double the number of legs on the chair.  Now, the new set
of legs have the same carvings on them as the old.  But now both set's
carvings can be modified independantly of one another.  Soon, all the
legs once again have different carvings, and you have 8 different legs
where you used to have only 4.
 
> > There are quite a few candidates for nascent organs ...
> Ok.  You might have something here.  Please post some references.

I haven't been able to make it to a library lately, so I'm going to have a
hard time being as specific as you light like.

Revision of the Dryinidae  (there is a recent one: you should be able to
find it.)  Read about the modifications to the tarsi forming a new claw
(females of some subfamilies only.)

Sphecidae of the World, Bohart and Menke.  Check what is written about the
fore tibial shield on males of the genus Crabro.  A really flashy organ on
some (the first time I saw one it was perched on a rock, and I was really
puzzled what it could be.)

If you really want a good example of nascent organs, consider the progression
from fish brains to mammalian brains.  Like the eye, it might be really
difficult to imagine precursors to the mammalian brain if we didn't have
such a good representation of brains similar to precursors.  Just as we
wouldn't imagine functional "half eyes", neither do we find "half brains".
Instead, we find a progression of well-adapted organs with gradual
additions that assume new functions (and sometimes old ones as well.)
Check some books by Romer, such as "The Vertebrate Story" and "The
Evolution of the Vertebrates" (I think.)
-- 

Mike Huybensz		...decvax!genrad!mit-eddie!cybvax0!mrh