What is the Theory of Evolution?

Evolutionists, tell me what the theory of evolution is

Posted by Mockingbird1 on September 11, 1998 at 21:22:39:

PK: Over the past few days I've run some thread on evidence of the theory of evolution. Adam, Sumac and Deb have had significant input. I have the impression that I don't get much argument from evolutionists because what I understand to be the theory of evolution is not what you understand the theory of evolution to be. Therefore, w/o an "A" or "B" question, or leading off w/ evidence against my understanding of the theory of evolution, please explain it to me in a thousand words or less. I'd like to get input from as many evolutionists as possible. Thanks!


First Response

Posted by Frank on September 11, 1998 at 22:08:42:

I don't know them all.

Here's my understanding of the main points in a nutshell:
1: Change in allele frequency over time.
2: Common decent of life on Earth.

Now the problem, for science, is which theory bests describes what happened. Is it "gradualism", where everything evolved, slowly to fill or better "fit its niche" in the environment that it lived? Is it Gould's, et al, "Punctuated Equilibrium" which incorporates some gradualism, I believe, but has that change could come "quickly", in 10's or 100's of thousand years, if a population was "cut off" from others of its own species? The cartoon "Darwinist" theory of evolution, survival of the fittest is more a creationist cartoon straw man than any accepted theory.

I don't really know about other theories or variations thereof.

I do know some of what "Evolution" is not:

1:  Evolution makes no claim on where or how life came to be.
2:  Evolution does not care how or why the universe came into existence.
3:  Evolution does not claim that cats give birth to dog (however watch Jerry Springer for another POV).


Response to Frank

Posted by Mockingbird1 on September 11, 1998 at 23:15:40:

PK: A lot of this looked familiar to me. The cat and dog one is of course interesting. Are you basically trying to distance yourself from Jerry Springer (a good idea) or just because you see species "B" coming directly from species "A" as saltation and therefore too abrupt to be evolution?

PK: (sigh) I just laid out an "A" or "B" question, answer if you feel like it, Frank. Thanks again.


Response to Mockingbird1

Posted by Frank on September 11, 1998 at 23:28:29:

I don’t know how much different an offspring would be from its parent, but just from common sense, I doubt if it would be much and probably not really noticeable. Now how much different the offspring of the offspring of the offspring, etc., for 10 generations would be in a Gouldesque PE environment, ie adapt or die, is beyond me.


Response to Frank

Posted by Mockingbird1 on September 11, 1998 at 23:37:16:

PK: I am reading you in tight sync w/ my understanding of the theory, the differences from one generation to the next might be a revolution, but aren't evolution in a meaningful sense (but I'm the one w/ the mental block).


Response to Frank

Posted by MEYER on September 11, 1998 at 23:22:29:

Change in allele frequency over time. What happened Frank? You remember I asked this question and got several answers until everyone got upset and decided I was talking about biological evolution? And the final definition, in which you were admit about was "change in allele frequency over time".

Frank; I don't really know about other theories or variations thereof.

I do know some of what "Evolution" is not:
1:  Evolution makes no claim on where or how life came to be.
2:  Evolution does not care how or why the universe came into existance.

Well, you are getting behind. Haven't you heard of cosmological evolution? It's the new theory that is replacing change in allele frequency. It covers the origins of life throughout the universe, even the Big Bang. Elementary students are getting this shoved down their throats these days. No longer is it just Biology, now there is Exobiology, Astrobiology to go with it, and cosmological evolution is the governing rule for all life in the universe. The only thing is, no one has found any other life. But that's never stopped evolutionists before in using the imagination.
Of course with these new "scientific" theories with "scientific facts", no wonder you all have forgotten what the definition of evolution is.


Response to MEYER

Posted by Frank on September 11, 1998 at 23:47:05:

I can't say that I ever told you that. If I did, I was wrong to say such a thing.


Second Response

Posted by Rod on September 11, 1998 at 22:51:08

One thing you need to understand is the "fact" of evolution and the "theory" of evolution.  That all living things evolve is a fact. We observe this, we see genetic evidence, and we have fossil evidence.   This is the "Fact" of evolution.

The "Theory" of evolution attempts to explain what we see and how it happens. The best known theory is Darwin’s "Natural Selection", or "Descent with Modification".

There are other theories; Genetic Drift, Sexual Selection and Punctuated Equilibrium are a few.  Understanding this difference is a good start.


Response to rod

Posted by Frank on September 11, 1998 at 22:56:56:

The Fact of Evolution is no different from the Fact of Gravity. Like Evolution, we know Gravity exists, but we don't know how either really work.

Gravity

1: Waves
2: Particles (Star Trek's "gravitons")
3: Interaction between mass and the "fabric of space-time" (which goes into other unexplored lands)
4: Etc.

Evolution
1: PE
2: Decent of Modifications
3: Sexual Selection
4: Etc.


Response to Frank

Posted by Stephen Charchuk on September 11, 1998 at 23:13:48:

A better term would be "The Natural Law of Evolution". This is a law in the sense of:

Law:

4. A generalization based on recurring facts or events (in science or mathematics etc)


Response to Stephen Charchuk

Posted by Kevin Kamberg on September 12, 1998 at 03:47:29:

The "fact" of evolution is the observed microevolution. The "theory" of evolution is macroevolution. The first is a known and the second is an assumption.

As Mockingbird1 has previously pointed out, it's pretty hard to determine fossil species with any real accuracy when there is no way to accurately determine which animals could mate with which others to produce fertile offspring.

Response to Kevin Kamberg

Posted by Deb on September 12, 1998 at 08:04:25:

And as I have repeatedly tried to point out to Mockingbird, the BSC is an operational definition only and is not so much used in practice to identify species but to confirm or disconfirm them after the fact. And even then it is not neat and tidy.

Look at it this way--we've all heard that when a scientist smokes out the canopy of a rainforest tree and ends up with a cartload of insects, upward of 60% of those insects are new species. How does he or she know this? Does said scientist sit around and try to mate each new bug to its fellows? No--they are new species because they look different. Just recently that large bovid was finally spotted in Viet Nam--a new species (at least). Have the describers attempted to mate this animal to others to see what happens? Of course not--it looks different, so it is a new species.

The plain fact is that the vast majority of species are identified as such on morphological grounds. Don't fall into the trap PK has of reciting BSC as a mantra. It just simply is not as practically useful as he wants everyone to believe.


Response to Deb

Posted by Mockingbird1 on September 12, 1998 at 18:01:17:

PK: I think that we agree to some extent that the initial identification is morphological - looks like a duck. Confirmation that a form is a species via observation of mating habits and results is desirable and unattainable for life forms that exist only as fossils. It is also useful to note the exceptional cases where life forms look the same and are in fact two distinct species.


Third Response

Posted by SGTex on September 11, 1998 at 22:59:34:

Good evening, M-bird1

Thanks for asking. The theory of evolution began as an elegant and plausible scientific account of the mechanism whereby new species have developed through natural selection. Its general tenets have stood up well to an onslaught of emotional and religious objections and are presently so well-substantiated as to be something of a given in the field of biology, to the great chagrin of fundamentalists.

During this century other advances in rationalist-materialist understanding have meshed with the biological evolution theory to supply a most thorough description of the development of all things, so that it is quite accurate and proper to refer to the evolution of the chemical elements and the evolution of complex chemical systems early in the history of Earth.

This debate board exists because the theory of evolution is so much more than that. Christian philosophy is so heavily invested in prescientific dogma of the supernatural that it rightly regards evolution theory as an anathema. Christians don't usually argue against other standard science---gravity, atomic theory, the germ theory of disease---but when it comes to evolution, there is an urgent and frantic denial, emotions run high and objectivity goes right out the window. Why?

Because evolution theory (and all the knowledge that is seamlessly continuous with it) has fully defined and explained what life is and how it got here. "Evolution," i.e., rationalist/humanist/materialist naturalism, has supplied answers about the meaning and value of our existence, thus outdoing and showing up the pulpit. The monumental resentment will take another century to die down. Evolution theory manifests the two vehicles to Buddhahood, Learning and Realization. It is wonder and glory and purpose and moral imperative. It is emancipation.


Fourth Response

Posted by Paul Rothberg on September 11, 1998 at 23:27:00:

My definition of evolution is a scientific explanation of the diversity of life. So this includes phylogeny, i.e. patterns of common ancestry, the branching of living things. (Despite the textbooks this is still a very active area of investigation.) It also includes what forces produced the observed patterns. The most interesting of these is natural selection.

I do not directly research evolution, but when I read things that are outside my field I very much enjoy articles on evolution. One reason is that many of them deal with genetics and understandable to me. The other is that evolution gives the big picture. Why are things the way they are? Why does life work in such a weird way? The answers come out of evolution studies and are very beautiful.


Fifth Response

Posted by Sumac on September 14, 1998 at 01:32:39:

There is 'evolution' and then there are 'theories of evolution'. Evolution is the change that has occurred to life over time. There is no disputing that evolution has occurred. Many species that are alive today were not alive 100 million years ago (or any arbitrary number in the distant past). Many species that were alive and flourishing 100 million years ago (ditto parenthetical) are extinct today. There has been a change in the forms and diversity of life over the history of earth. That is 'evolution'.

In contrast, the 'theories of evolution' are man-made, scientific constructs that attempt to explain how evolution has occurred. There are several theories that are not all mutually exclusive. A major component of most - if not all - evolutionary theories is the mechanism of natural selection (I won't describe natural selection since I assume most of the people reading these pages know what it is). Natural selection has been observed on enough occasions to be considered a fact, so any reasonable theory must incorporate it into the model. Other mechanisms such as random genetic drift, sexual selection, speciation by infestation, etc. have also been observed so these must also be incorporated into the model or it will be incomplete. Some "evolutionists" try to simplify the theory by stating that evolution is simply a change in allele frequency over time. I happen to disagree with this definition since it does not account for all of the changes that we can observe.

Inherent in any model of evolution is the idea of common ancestry. That two species can arise from one is no longer in question. We have observed speciation events on numerous occasions. What is in question is the extent to which common ancestry can be assumed or extrapolated. Since we have not actually witnessed a dog-to-cat transition in real time (or whatever the current need-to-see example is), we must make inferences as to the extent of common ancestry from the available data. We can see from the fossil record that there was a time when the only life that existed on Earth was unicellular. Later, there was other life like sponges and other soft-bodied animals. Then there were hard-bodied animals. Then plants. Then land animals. There was a progression through time in the appearance of mollusks, fishes, amphibians, reptiles, and mammals. Non-flowering plants appeared before flowering plants. These are all facts that we can observe from the fossils that they have left behind. And not only that; we have found examples of both extinct and modern life that are so intermediate between forms that they can not be easily classified as one type or another.

The best explanation to explain our observations of current and past life is that all of modern life started from a common ancestral population. The origin of that ancestral population is not known. However, there is some evidence to indicate that abiogenesis could have occurred (some would even say that it must have occurred). As we learn more about life, the theory (or theories) necessarily change since science is a dynamic process. So, what may be our understanding of how things work now may be different than our understanding of how things work later. Did that answer the question?

 

 

 

 
 
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