How do you define the Theory of Evolution?

The mechanisms involved in the changes from the first living (which in itself is a fuzzy concept to define) organisms; forms of Prokaryotes, to the variety of forms of life we observe today.

But, then, I'm not a Biologist by any means; so I'll leave it all up to the specialists.

Second, just what is the Theory of Evolution? A theory explains a phenomenon, so the theory of evolution explains evolution. Do you have any idea what that means?

And if the explanation is any good, then you can make predictions for future discoveries.

Those predictions can be used to test the explanatory power of the theory:

If they come true the theory would appear valid, and it can be used for further predictions;

If they don't come true the theory would appear invalid, and a better explanation is needed.

Enjoy

I deliberately did not include mechanisms of evolution or fitness in my definition.

Which is why it's a shit definition, if you'll excuse my bluntness.

The purpose of a theory of evolution is to explain the mechanisms of evolution. Anything which doesn't attempt to is not a theory of evolution.

The modern theory of evolution would require a book to explain. My hamfisted attempt to summarise in a brief paragraph would go as follows:

Organisms have heritable characteristics; and the primary mode of inheritance is through DNA. Heritable characteristics which increase the probability of an organism leaving offspring are likely to increase in frequency in a population. The likelihood of leaving offspring we refer to as fitness. DNA replication produces imperfect copies, so new variety is constantly being introduced. Fitter new varieties will tend to increase in frequency. Fitness is relative to the environment, so two populations placed in different environments will tend to diverge,

This seems incomplete, but I was trying to sum up the main points in as few words as possible, and I am not a biologist.

Using RAZD's link and going to "THE ORIGIN OF SPECIES. 6th Ed" p 429

quote:

---

There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.

---

Note Darwin says "into a few forms or into one". Earlier in the book he makes it clear that he favours "one".

So yes I maintain that common ancestry, from one or a few common ancestors, was a core part of Darwin's theory, and the ToE today.

I also maintain that the consensus view today is for universal common ancestry as exemplified in Theodosius Dobzhansky's "Nothing in Biology Makes Sense Except in the Light of Evolution".

I think that's a reasonable definition. Well stated.

I don't. It is defined by scientific consensus, not us.

Then enlighten me; how is it defined by the scientific consensus?

CRR writes: Note Darwin says "into a few forms or into one". Earlier in the book he makes it clear that he favours "one".

Darwin, 1859 writes: "Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed

You're a weird crew you creationists. Darwin's work is for science historians and general interest - it's not the bloody bible and it's not modern science. It doesn't matter what Darwin said, he's not Moses. He happened to be proven right on pretty much everything but it wouldn't matter if he wasn't - we'd be using our current understanding, not his.

LUCA may be the single source of all life or it may not be. Darwin was correct to say 'probably'.

As far as I'm aware, this is science's current view.

quote:

---

The most commonly accepted location of the root of the tree of life is between a monophyletic domain Bacteria and a clade formed by Archaea and Eukaryota of what is referred to as the "traditional tree of life" based on several molecular studies starting with Carl Woese.[31] A very small minority of studies have concluded differently, namely that the root is in the domain Bacteria, either in the phylum Firmicutes[32] or that the phylum Chloroflexi is basal to a clade with Archaea and Eukaryotes and the rest of Bacteria as proposed by Thomas Cavalier-Smith.[33]

---

So yes I maintain that common ancestry, from one or a few common ancestors, was a core part of Darwin's theory, and the ToE today.

Original common ancestry is an outcrop of evolution, a prediction reached when following the theory and the evidence to a logical conclusion, rather than a foundation. This is what the evidence shows: daughter populations descending from a common parent population, that is also a daughter population descendant from a more ancient common parent population, along with the formation of nested hierarchies. The process of evolution explains how this pattern develops, but it does not require it.

Theories explain evidence, so the ToE explains the evidence of nested hierarchies.

Theories make testable predictions, so the ToE predicts an original common ancestor pool. We test this prediction by looking for new evidence that supports or invalidates it.

Enjoy

Common descent is a conclusion/prediction of the ToE, it's not the ToE itself.

But he's been told this before - it doesn't make any difference.

The word evolution can have multiple meanings such as;
1. a gradual development [the most basic definition]
2. a gradual development, esp to a more complex form
3. a change in the characteristics of a population of animals or plants over successive generations [biology]
4. a heritable change in the characteristics of a population of animals or plants over successive generations [biology]
5. a change in allele frequency in a population over time [biology: population genetics]

So we can talk about the evolution of language, the motor car, species, or many other things.

But these are all definitions of the WORD evolution and not the THEORY of Evolution (ToE).

We can talk about a theory of Cosmic Evolution or the theory of the evolution of the Solar System but when we say the Theory of Evolution without some addition or qualification it is generally understood as the modern version of Darwin's Theory of Evolution by Natural Selection. (Although I understand Lamark's theory of evolution is making a bit of a comeback with epigenetics)

Of course Darwin's theory has been modified since it was first proposed and some would say that there are today several theories of evolution all derived from Darwin's theory. Darwin made several specific claims in his theory and likewise the modern theory/theories make specific claims.

Darwin took a whole book to discuss his theory and ague his case but many people (e.g. Kerkut, Coyne, Gould, Weintraub) have given definitions of one paragraph or less.

So when I proposed this topic I asked for your definition of the Theory of Evolution. By all means borrow from another source; in which case it is polite to acknowledge it. My definition was a single sentence. Can you give a definition of the ToE in no more than a couple of paragraphs. (If Coyne could manage it I'm sure you can.)

CRR writes: So when I proposed this topic I asked for your definition of the Theory of Evolution.

You've had stacks of definitions. Your request for definitions is disingenuous - this is all you're trying to do:

Tangle writes: But by allowing species to change they [creationist] opened the gate to evolution. So now the great wriggle is to stop evolution at a convenient point - they have to allow change, but not so much change that it can harms creation itself. Hence 'kinds' - an undefinable idea allowing as much or as little change as is necessary for any particular organism just so long as they can be on that boat. This is tricky. The reason that CRR is being so pedantic about definitional issues of the ToE that no-one in science cares too much about is because he absolutely must find a definition which removes the logical conclusion of common descent. His job here is not to define the Theory of Evolution but to define OUT of the ToE common descent. He now needs to stop evolution at some convenient point for his beliefs to continue make some sort of sense to him despite the accumulation of evidence that they don't and that they can't.

CRR writes: (Although I understand Lamark's theory of evolution is making a bit of a comeback with epigenetics)

It isn't. Almost all epigenetic markers are removed during gamete production, so most epigenetic markers are not passed on. Of the ones that are passed on they only make small changes and only last a generation or two. Epigenetics is incapable of explaining the differences seen between species, and is also incapable of explaining long term evolutionary changes.

Of course Darwin's theory has been modified since it was first proposed and some would say that there are today several theories of evolution all derived from Darwin's theory.

There is still just one theory of evolution.

Darwin took a whole book to discuss his theory and ague his case but many people (e.g. Kerkut, Coyne, Gould, Weintraub) have given definitions of one paragraph or less.

Those paragraphs are still incapable of describing the entire breadth of the theory.

So when I proposed this topic I asked for your definition of the Theory of Evolution.

And that is a set up. You want to force people to propose a short definition that will necessarily be inadequate in explaining the entire breadth of the theory. You will then point to this inadequacy as a problem for the entire theory, but the only problem is in your expectation that a theory as broad as the theory of evolution can be boiled down to one sentence or one paragraph.

the root of the tree of life

CRR writes: the root of the tree of life

The Santa Clause

What good is a theory of origin of species that doesn't explain the origin of the first species?

What good is it? Well, it can explain all the others.

And this is in fact what it does. Sheesh, how long have you been posting here and you're still whining and lying about mere definitions rather than any substantive question of fact?

Why?