From: onar@hsr.no (Onar Aam)
Newsgroups: talk.origins
Subject: Re: Clarification on Microevolution and Macroevolution
Date: 16 Oct 92 18:22:40 GMT
Organization: Rogaland University Centre

>>> 4) Gene increase happens all the time. I understand ome species of mosquito
>>>gained a near-immunity to a common pesticide by doubling the gene that codes
>>>for a protein that meabolizes the pesticide-- and this happened in recent
>>>times. Given a few billion years, genome expansion is not all that unlikely.
>>>(Does anyone have a reference for this?)
>>
>>This is exactly what I am saying. Although I never said that geneduplication HAS
>>to have great impact on the species. In most cases it does not. (Hence all the
>>junk DNA)
>
> I'm trying to understand your point, then. Are you saying that the role
>of gene duplication (or other forms of genome expansion) is not fully
>appreciated in modern evolutionary theory, or what?

Yes, I am. I don't regard the enourmous genomeexpansions as "something that just
happens". I suspect that there is a mechanism behind it, perhaps an evolutionary
one. I am not saying that gene duplication evolved, although the thought is
interesting. Too me it seems that no mechanisms has evolved to prevent gene
duplication. On the conrary, it seems like the effect ofgene duplication has been
strengthened. Is this a way to make evolution more efficient? Remember, 3 billion 
years was needed to produce multicellular life. Only 3/4 billion years was needed
to produce beings with often 100 times more genes than bacterias. THAT I think is
no coincidence.


[some deleted]

>>> This is almost exactly opposite to the way evolution is proposed to act.
>>>Or is that your point? I mean, the general idea of evolution is that
>>>if the *environment* changes the species alters to fit the new environment.
>>>This has been recently extended to note that small, geographically isolated
>>>populations are much more sensitive to environmntal pressure and much more
>>>likely to speciate under such conditions.
>>>(Again, I'm no biologist, and I'd appreciate someone summarizing that better.)
>>>
>>
>>Again, what you say is absolutely true. I never stated WHY it happened, I merely
>>stated HOW it happened. Thus, my statement does not contradict yours, does it?
>
> So you are saying that current evolutionary theory has the cause and effect
>reversed?
> What current evolutionary theory says (as far as I understand it) is that
>mutations, gene duplications, etc. happen at a fairly constant rate. (Except
>maybe in some bacteria.) If a population is both small, and isolated from
>other groups of the same species, then a given mutation, if beneficial,
>has a much greater chance of spreading throughout the population.
> Given a bit more time, and a few sets of mutations occurring, the isolated
>subgroup may become unable to breed with the wider population; i.e. a new
>species emerges. If the geographical isolation is later removed (an earthquake
>opens up a previously isolated valley, etc.) the two species, old and new,
>will intermingle. If the new species still competes with the old species,
>and is better at competing, it will tend to drive out the old species.
> What you seem to be proposing is that a new species will emerge if the
>new mutation is such that it 'destabilizes' the previous equilibrium. In
>the section I originally responded to, you seem to be saying that a species
>which is already adapted to its environment still has selection pressure
>to make major changes or something... What in the above characterization I
>gave do you disagree with, or would like to add to?



I have never thought of it that way. Normally when species are isolated for long
periods of time they tend to become LESS competitive than their competitors. Ex.
Look at the animals of Austraila. They have no natural enimies in carnivores.
Release some rabbits from Europe or a frog from America and all hell's breaking
loose... Normally if a specie is adapted it stays like it is until it HAS to
readapt. This means, I think, that I pretty much agree with you. Originally I
didn't state a cause, but that doesn't mean that there is no cause....

>>The fossil record supports long spans with no (read small) change and then
>>sudden change. It is called Punctuated Equilibrium. (the change need not be great)
>
> 'Sudden' on what scale? The timescale of the kind of mutation you seem to
>be proposing is effectively instantaneous; speciation usually takes at *least*
>a few hundred years (generally) I understand.


The 'sudden' I am talking about is from one generation to another. This is an
extremely punctuated kind of evolution. Of course I am not saying that from one
generation to another a completely new feature comes along. What I am talking
about are changes which trigger a strong selective preassure. THEN the specie
gradually adapts until equilibrium is reached (and the new feature has evolved).
( This might be all from 100s of years to 1000s of years, depending on the 
selective preassure.) How common this is I do not know, but I suspect it to be not
uncommon at least.

[some more deleted]

>>Ray, I am sure that you know that biological clocks are governed by chaotic
>>mechanisms. Some of these have already been well mapped. That evolution is also
>>governed by chaotic mechanisms is also fairly well detected - and for the same
>>reasons.
>
> We know biological clocks (like heartbeat, etc.) are governed by nonlinear
>systems that can be pushed into chaotic regimes, yes. And many biological
>structures can be successfully modeled as fractals (like lungs, blood vessels,
>etc.) But that is because we can do the calculations and measure the effects.
> I would *really* like to see how this effect has been detected in 'evolution'
>(hopefully in some journal article?).

I don't have any immediate references, but try out stuff on supercriticality and
perhaps the popular book 'The arrow of time'. Author I do not recall.
> Biological systems (cells,organs,organisms etc.) are all

>>"far-from-equilibrium" systems; they need a constant flow of energy to retain the
>>potential that drives them. Take away the energy (food) and they die. An analogy
>>can be produced for evolution. Life as a whole is ultimately a
>>"far-from-equilibrium" system with its main energy source from the sun. The
>>energy is expressed in form of natural selection.
>
> Um, actually, I think the energy is expressed in metabolizing and
>reproducing. Natural selection is at least a second-order effect.

Of course it is. Natural selection is the energy expressed in competition
and "problem solving". 

>>                                                   If a gene is subject to
>>selective preassure then it will be preserved (potential retained). If not then
>>the gene will erode (die). This system is clearly a nonlinear process. And you
>                                                     ^^^^^^^^^ ^^^^^^^
>Not all that is nonlinear is chaotic/fractal, even though all that is
>fractal/chaotic is nonlinear.

I know. I didn't use the term 'nonlinear' without purpose, you know. Perhaps
evolution also is chaotic, but it is at least nonlinear. This is given by the
itterative nature of evolution. Besides, all the conditions for nonlinearity is
present. 

>>yourself stated the problems: we don't have a clue to how evolution "really"
>>works. That is perhaps some of the greatest tasks in biology in the future. Heavy
>>research is needed. And therefore I don't have the capasity to answer your
>>questions.
>
> okay, so this is just your best guess/speculation, right? You're saying you
>*suspect* this but can't prove it yet, I take it?
> (That's not an attack, I'm trying to make sure I understand what you
>say.)

Yup.
Newsgroups: talk.origins