Vanderzyden

I'm a new participant to these forums, so let me start with a request for a definition:

What is evolution, in the neo-Darwinian sense?

Confusion abounds in naturalistic circles. So, despite my efforts, I've been unable to find a solid, concise articulation. So please help me, if you would. Perhaps you could simply refer me to a quotation from your favorite Darwinist.

Non-praying Mantis

Easy.

Evolution is a change in a population's gene pool over time

NPM

CRDbulldog

To understand neo-Darwinian evolution you must understand "evolution". Evolution is simply change over time. And when it comes to biological species, no one -- not even the most hard core young earth creationists (YECs) deny this. YECs limit this type of evolution to "microevolution" which is roughly defined as a small change. The next step up in the evolutionary scale of things is "descent with modification". What this says is that species transmutate one into another. An extension of descent with modification is "common descent" which means that all species share a common ancestor. This is what Stephen J. Gould referred to as the FACT of evolution. In other words, the evidence for this is OVERWHELMING and is accepted by virtually all competent scientist familiar with the evidence. Neo-Darwinism goes over and above this by ascribing a mechanism by how such change came about. That mechanism is natural selection -- inheritable traits that increase an organism's fitness (fitness here is defined as the ability of an organism to transmit its genes to succeeding generations) will be retained while those inheritable traits that decrease an organism's fitness will be eliminated naturally.

It is here that the real controversy in neo-Darwinism lies. Virtually all scientists, and all creationists for that matter, agree that natural selection exists. Virtually all scientists agree that is very important in speciation. The controversy lies in its relative importance with respect to other potential mechanisms.

Creationists would have you believe that there is a dichotomy; either you believe speciation happened by natural selection or Goddidit. This is NOT what any scientist working on the origin of species believes. There ARE other mechanisms besides natural selection. Here are some:

(1) NEUTRAL SELECTION -- This mechanism has been championed by Mootoo Kimura. He has shown that most mutations at a molecular level neither significantly increase or decrease the organisms fitness. This may be a way in which variation -- the key ingredient for natural selection to cause a change -- can build up in an organism's gene pool over time. A change in the environment may then bring out beneficial characteristics that had previously been hidden.

(2)SPECIES SELECTION -- Species exhibit some of the characteristics of individuals. Punctuated equilibrium suggests they have a life span and then spawn new species. Furthermore, there are interspecific competetions that contribute to the "fitness" (in this case, read "fitness" to mean "survival") of the species. Stephen J. Gould postulates that selection working at this level could be responsible for speciation.

(3)SELF-ORGANIZATION -- This has been championed by Stuart Kaufman. In any complex system there will be interactions between the members of these systems. These interactions arise spontaneously and create a type of "order for free".

Note that these potential mechanisms are not mutually exclusive. NOR do they exclude natural selection. The question is do they exist and if so, how important is their role in speciation? Neo-Darwinism can encompass any or all of these other mechanisms quite well. Remember no scientific theory is considered complete. ALL scientific theories are subject to revision with the advent of new information. Neo-Darwinian theory is a healthy theory. It's core is intact and not doubted by the vast, vast majority of scientists. That does not mean that it is set in stone, however. There is active research going on which will undoubtedly change certain details of the theory. Creationists would have you believe this casts doubt on the entire theory. This claim is of course ridiculous.

Hope this helps.

[ August 12, 2002: Message edited by: CRDbulldog ]</p>

pz

No, confusion does not abound in "naturalistic circles". The problem is that evolution is a large, complex theory that encompasses multiple scientific disciplines, and credulous lackwits who have been weaned on simplistic superstitions like to petulantly demand that it be distilled down to a single quote from some grand authority.

Go read a book. Try the texts from Futuyma or Ridley to start.

If you're really serious, take some basic biology from your local community college (presuming, of course, that the curriculum hasn't been gutted of substance by pressure from the uneducated fundamentalists toads who tend to make loud noises in many communities). I suspect that you don't know enough biology to make a decent fortune cookie aphorism, and most of what you think you do know is wrong.

TooBad

Hmmmm...
In the space of 22 minutes, apparently, Vanderzyden has studied, absorbed, criticized and firmly rejected the Darwinian account. Impressive.

[ August 12, 2002: Message edited by: TooBad ]</p>

Principia

Nah, I've seen worse at ARN with philosopher-morons like mturner, warren_bergerson, bertvan, RFH and co. They all think that their philosophical musings can make up for serious deficiency in actual knowledge about biology. DNFTT

[ August 12, 2002: Message edited by: Scientiae ]</p>

RufusAtticus

My working descriptions:

(Biological) Evolution: Change in the properties or frequencies of properties of populations of organisms over time.

Microevolution: Evolution apparent within a biological species, which is a nearly reproductively-isolated population of individuals.

Macroevolution: Evolutionapparent between species or higher taxa.

These are descriptions not definations, since there is no single correct or standaradized way of distilling such complex topics of biology into sucinct definations. Evolution is not a object you can point to and say, "see we chose to name that thing 'evolution'."

~~RvFvS~~

Vanderzyden

CRbulldog,

Thanks for your reply. If I have it right, neo-Darwinian macroevolution may be simply defined as:

descent with modification by means of natural selection

I appreciate your help with the definition, for in order to have command of a subject it's necessary to have a concise, conceptual understanding. You probably have little patience for those who would resort to name-calling and hide behind such ignorant diversions as "it's a large, complex theory". To that end, let me investigate this a bit further.

You'll agree that any good definition is precise, and is substantiated by what may be found in the real world. Yet--it may surprise you--many life and physical scientists are questioning the relevance of a definition which has no supporting evidence. Now I would say that strong controversy remains with respect to both the claimed product (i.e. modified descendants) and the mechanism (e.g. selection), since there is nothing conclusive to substantiate the definition. There are no transitional forms in the fossil record and empirical observations have yet to reveal that adaptation may be extrapolated to be a mechanism for the generation of entirely new species. Furthermore, as you imply, it is difficult to find neo-Darwinians who agree (e.g. Gould is in diametrical opposition with, say, Dawkins). Faced with this confusion, how is it that you are able to declare that the "core is intact" for this "healthy theory" ? Your comments are most welcome.

Another thing: I would ask you to consider an extension to this definition: abiogenesis. As you may know, this is the origin of life from non-life. How would you include that in your definition? Please explain.

Incidentally, I wonder if you could clarify something: It does seem that you are stereotyping any non-Darwinian as a (young earth) creationist, and that they maintain identical, narrow, irrational beliefs. Why is that? Please explain why the phrase "God did it" is intrinsically irrational.

I can answer these questions and grave objections only on the supposition that the geological record is far more imperfect than most geologists believe. It cannot be objected that there has not been time sufficient for any amount of organic change; for the lapse of time has been so great as to be utterly inappreciable by the human intellect. The number of specimens in all our museums is absolutely as nothing compared with the countless generations of countless species which certainly have existed. We should not be able to recognise a species as the parent of any one or more species if we were to examine them ever so closely, unless we likewise possessed many of the intermediate links between their past or parent and present states; and these many links we could hardly ever expect to discover, owing to the imperfection of the geological record.

-- Charles Darwin, Origin of Species

Defiant Heretic

Here's how Darwin originally described evolution:
While there have been many different theories about exactly how the genes change, this is the basic foundation of the theory of evolution.

Albion

Yes, I think the notion that evolution has no supporting evidence will come as a surprise to scientists the world over.

You can see descent with modification in action every time you look at a person and realise that he isn't identical to either parent. You can see natural selection at work when you look at a dish of bacteria interacting with antibiotics. The only controversy about the existence of variation and natural selection is in the minds of creationists.

That is nonsense.

So is that. Speciation has been observed in the lab and in the wild.

They have both said that they're arguing about a fairly minor matter, which is the extent to which punctuated equilibrium operates during the evolutionary process. Richard Dawkins has said that smooth evolution doesn't mean a completely constant rate. Stephen Jay Gould has said that punctuated equilibrium is a special case of the evolutionary process, not something completely different. They're a lot closer than you'd like to think. Gould was always rather fond of overstating his case (not just about this), and considering that he knew how creationists like to make hay with whatever they have at hand, he could have been a bit more discreet. This is only a diametrical opposition in the minds of creationists.

Because it is. Sorry, but it is.

Abiogenesis is irrelevant. It doesn't matter whether the first life (whether it was nucleic acid replicators or simple cells - however you want to define it) developed spontaneously, was imported on comets, was synthesised by space aliens, or was created by God, evolution still works the same way.

It isn't covered by the parameters of science. There's no way you can apply the scientific method to an entity that exists outside the laws of nature. "God did it" is as much a description of the whole evolutionary process as it is of young-Earth creationism - and once you've said "God did it," that leaves you scientifically precisely where you were before you said it. It hasn't explained a single thing in the scientific frame of reference. It isn't based on evidence because it can be used to explain everything, no matter what; it's based on faith and personal revelation. It isn't something you can deduce rationally.