Definition of evolution

@Dave Allen,

Dave Allen:

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observe that The Selfish Gene was not the only work quoted. The Extended Phenotype was written for his peers.
No, it's pop science.

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bunk.show it. show what you are hinting about.
"Now to what matters; whether or not the same equivocation of gene and genetic unit occurs broadly throughout teaching literature."

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of course it's not. How could admitting something ( unless using the same word in more than one way), be equivocation ?

Exactly.

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talking about, admitting different meanings are used, is not the opposite of equivocating.

Nope - you had it - but you lost it again.

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I didn't say poular science is popular ideas. try again.

"I never stated that The Selfish Gene is peer reviewed scientific literature. we all know it is not. Nothing shady about showing what popular ideas are."

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adding punctuation might help me understand that sentence
Capital letters at the start and full stops at the end are typical of properly punctuated sentences.

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You've twisted the purpose of my showing it, to say that I was supposedly purporting to show what peer reviewed literature says.

It's obvious what your plan was.

The astonishing work above needs a bit of analysis, but meanwhile, here is some reading that may help outline the situation vis a vis how "gene" may be perceived.
it may help to solidify an appraisal of what one is reading, to be able to classify the kind of "gene" meaning we are dealing with in particular instances. e.g. a "Nominal" kind of meaning, or "Instrumental" meaning. Or the categorization they call the "Post-Genomic" meaning.
http://philsci-archive.pitt.edu/archive/00002641/01/Genes_postgenomic_era.pdf Quoting on Williams' gene and Dawkins' elaboration on the theme

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"I use the term gene to mean "that which segregates and recombines with
appreciable frequency."" (1966, 24) The critical property of an evolutionary gene is not
that it codes for a protein, but that is a unit of recombination - a segment of chromosome
which regularly recombines with other segments in meiosis and which is short enough to
survive enough episodes of meiosis for selection to act upon it as a unit (see the careful
elaboration in Dawkins 1982, 86-91).

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Geneticists continue to make use of classical genetic techniques to identify regions of
chromosome in which nominal genes may be located. Even when the explicit aim of this
work is to identify nominal genes, the conceptualization of the gene that is actually used
to do the work is the classical, instrumental conception. This is shown by the fact that
well-conducted work of this kind, free from any experimental error or errors of reasoning
may locate a candidate 'gene' that does not correspond to a molecular gene, but to some
other functional DNA element, such as an untranscribed regulatory region. As Marcel
Weber concludes, after an insightful comparison of Mendelian and molecular analyses of
Drosophila loci, "even though the classical gene concept had long been abandoned at the
theoretical level, it continues to function in experimental practice up to the present."
(Weber

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@memester,

Wow... 8 pages of posts since the last time I logged on.

memester;121458 wrote:

Evolution is change in organisms. That's the definition that is never proven wrong, never allows exceptions.

When I shaved this morning, I was a changed organism afterwards. This is not evolution.

Shouldn't evolution's definition include some aspect of heritability??

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@memester,

well what about the Cambrian Explosion, eh? That put a cat amongst the pterodactyls, even in Darwin's day:

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The Cambrian explosion...was the apparently rapid appearance of most major groups of complex animals around 530 million years ago, as shown by the fossil record. This was accompanied by a major diversification of other organisms, including animals, phytoplankton, and calcimicrobes. Before about 580 million years ago, most organisms were simple, composed of individual cells occasionally organized into colonies. Over the following 70 or 80 million years the rate of evolution accelerated by an order of magnitude (as defined in terms of the extinction and origination rate of species) and the diversity of life began to resemble today's.

The Cambrian explosion has generated extensive scientific debate. The seemingly rapid appearance of fossils in the "Primordial Strata" was noted as early as the mid 19th century, and Charles Darwin saw it as one of the main objections that could be made against his theory of evolution by natural selection.

The long-running puzzlement about the appearance of the Cambrian fauna, seemingly abruptly and from nowhere, centers on three key points: whether there really was a mass diversification of complex organisms over a relatively short period of time during the early Cambrian; what might have caused such rapid change; and what it would imply about the origin and evolution of animals. Interpretation is difficult due to a limited supply of evidence, based mainly on an incomplete fossil record and chemical signatures left in Cambrian rocks.

(from Wikipedia)

Obviously there is a lot of literature on this topic already. In my mind it suggests that there are still some open questions about whether adaptive necessity is the main driver of the evolutionary process. Prior to Darwin, many biologists believed in the 'laws of form' - that certain forms were more likely to appear or predominate. However this thinking has generally been rejected now in favour of the principle of natural selection as being the sole determinant of form.

Any thoughts on whether the 'Cambrian explosion' detracts from the hypothesis of 'adaptive necessity' as the main cause of evolutionary development?

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@jeeprs,

jeeprs;121703 wrote:

well what about the Cambrian Explosion, eh? That put a cat amongst the pterodactyls, even in Darwin's day:Any thoughts on whether the 'Cambrian explosion' detracts from the hypothesis of 'adaptive necessity' as the main cause of evolutionary development?

Just prior to the Cambrian explosion "in geological time" was the snowball earth phenomena where the temperature of the planet dropped to -50 C, the oceans froze and a mass extinction event occurred. The dramatic climate change which ended the snowball earth phenomena created new ecological niches and the mass extinction event made sure that were voids that could be filled. In fact most mass extinction events are followed by a flourishing and diversity of new life (the dinosaurs extinction was exploited by the mammals).

There certainly is a notion that evolution tends to converge, and that evolution is not a steady progressive event but one that is punctuated by much more rapid evolution during certain periods of time as above. Just a thought. The role that climate change and mass extinction events play in the history of evolution gets lost in the focus on genetics, I would say.

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@memester,

so such things as climate change, mass extinction events, etc, might be seen as drivers of 'macro-evolutionary' trends, in distinction from the gradual processes by which, for example, the beaks of finches are differentiated.

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@prothero,

prothero;121704 wrote:

The role that climate change and mass extinction events play in the history of evolution gets lost in the focus on genetics, I would say.

Genetics is used for phylogeny / ancestry and it is one of several methods of dating species. To this end, it is quite appropriately used to help interpret the effects of major global events on biodiversity.

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@jeeprs,

jeeprs;121705 wrote:

so such things as climate change, mass extinction events, etc, might be seen as drivers of 'macro-evolutionary' trends, in distinction from the gradual processes by which, for example, the beaks of finches are differentiated.

You might wish to look at Gould's punctuated equilibrium theory and the theory of evolutionary convergence. Gould does not so clearly correlate periods of rapid evolutionary change with mass extinction events and major geological changes as the above but it fits in with his view of the history of evolution. Large stretches of time when little major evolutionary change takes place. Again the use of cross specialty information gives a better picture than just the perspective of one discipline. I have been consistently objecting to viewing evolution as purely or even mostly just a genetic phenomena.

Just as an aside (and just for you jeeprs) the notion of evolutionary convergence could be viewed as nature trying to acheive "certain forms" sorta Platonic in a sense.

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@memester,

you know me too well:-)

I rather like Stephen J. Gould actually. I have been reading some of his essays and they are first rate. And the 'puncuated equilibrium' model is indeed suggestive of some logic that drives morphology, over and above adaptive necessity.

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@Aedes,

Aedes;121697 wrote:

Wow... 8 pages of posts since the last time I logged on.

When I shaved this morning, I was a changed organism afterwards. This is not evolution.

Shouldn't evolution's definition include some aspect of heritability??

"Yes", it is evolution, and it "certainly" it should be able to include some aspect of heritability...therefore it is able to.

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@memester,

memester;121718 wrote:

Certainly, and so it does.

I only ask because you hadn't included that in the definition I quoted. So a "basic" definition needs to be something like "heritable biological change among organisms".

However, this definition needs to also include (under 'biological change') evolutionary changes to DNA sequence that do not result in an altered phenotype. A lot of inferences can be drawn from linkage analysis, which looks at the evolutionary changes in non-coding regions that happen to segregate with genes of interest.

---------- Post added 01-21-2010 at 11:54 PM ----------

memester;121718 wrote:

"Yes", it is evolution.

Shaving?

It may be evolution of my facial hair, or evolution of my daily ritual of self-beautification, but that's not what is meant by evolution (if we're trying to tighten up a definition that we can all agree on).

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@Aedes,

Aedes;121720 wrote:

I only ask because you hadn't included that in the definition I quoted. So a "basic" definition needs to be something like "heritable biological change among organisms".

no, my basic definition is precisely as I stated it, thank you.

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However, this definition needs to also include (under 'biological change') evolutionary changes to DNA sequence that do not result in an altered phenotype. A lot of inferences can be drawn from linkage analysis, which looks at the evolutionary changes in non-coding regions that happen to segregate with genes of interest.

But not that it NEEDS to explicitly say it includes it - rather it should be able to include, and it can.

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Shaving?

Shaved.

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It may be evolution of my facial hair, or evolution of my daily ritual of self-beautification, but that's not what is meant by evolution (if we're trying to tighten up a definition that we can all agree on).

It's not what is meant, but it's not what is not meant. Evolution includes everything, of course - everything about changes to organisms. There is no separation, no artificial distinction which dictates that your activities, your behaviours, your appearance, your elation or depression, are divorced from you, the organism, your phenotype, your phenome.

How do we a priori say that there is definitely not ANY connection between how meticulous you are - how neat you want your appearance to be, how concerned you are with social factors today - and...let's say...genetics ? How is it that you are able to determine this out of hand, Paul ?

If you cut off your head, it matters. Same with a toenail, but not quite as much.

So for the toenail freak, if they are testing for something about toenails, or hypothesizing, then yes, toenails can be a evolutionary topic of interest, as can warts.

But since warts or shaving are not topics that make or break my definition, I do not mention them one by one. that's not a basic definition. You might have the phenotype "freshly shaved" given you, if someone is studying shaved faces. I won't be mentioning every topic - as you seem to think is most desirable in a definition.

In all, it is you who has seemingly decided that my definition making is to be a committee sanctioned event, or a quilting bee, not I . However, you'll notice that I reject nothing, out of hand, and thereby anyone can accept it. It's THE most inclusive definition.

I don't give a rat's ass if you accept it or appreciate it. I'd be pleased to answer reasonable questions, though.

Just so you understand, this provision of a definition is not intended to be a summation of Evolutionary theory.

Now for a question that you might have an answer to; in your school of thought on this, if evolution is allele frequency change /population/time, and if there are no alleles of a gene, no mutation, then that gene, the DNA , has no measurable evolutionary effect. No allele-inspired differences going on at all, right ?

Is this correct ?

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@memester,

memester;121722 wrote:

no, my basic definition is precisely as I stated it, thank you.

Ok, well if that's the case then I object to your statement that "that definition is never proven wrong, never allows exceptions", and I think that it is too generic to function as a definition.

Non-heritable acquired changes to organisms cannot be included within a "basic definition" of evolution.

And while you're right that a non-heritable, acquired change like shaving MIGHT affect my own procreative capacity or survival, so might changes in the earth and the solar system. Variables that influence inheritance may be changes to organisms or they may be changes to the environment. So you're being arbitrary if you're including non-heritable biological changes for this rationale but excluding solar flares or droughts.

---------- Post added 01-22-2010 at 09:19 AM ----------

memester;121722 wrote:

if evolution is allele frequency change /population/time, and if there are no alleles of a gene, no mutation, then that gene, the DNA , has no measurable evolutionary effect. No allele-inspired differences going on at all, right ?

One particular locus may remain constant over a time period in which many other loci change.

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@Aedes,

Aedes;121762 wrote:

Ok, well if that's the case then I object to your statement that "that definition is never proven wrong, never allows exceptions", and I think that it is too generic to function as a definition.

it's all encompassing, if that is what you mean.

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Non-heritable acquired changes to organisms cannot be included within a "basic definition" of evolution.

I don't say they are in the basic definition. You can read my definition once more. See?

They aren't . Covered ? Sure.

BTW, have you ever inherited money ? And you figure it can have no effect on your success or groups' success ?

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And while you're right that a non-heritable, acquired change like shaving

I am right, but you are wrong, if you assume that I have taken into account, only that such a habit might have an effect on your future success.

Not only do I take that into account, but I also acknowledge what you do not even glimpse - that it is included precisely because we do not know what is at work. And in my estimation, a definition can help us learn.

We do not know the heritability of some facet of the behaviour that makes you maintain this particular standard of appearance, shaved rather than bearded, pay this amount of attention to maintaining appearances....where shaved face is but one aspect - AND as you mentioned, for the future we do not know what effect the always clean-shaven face will have on you and your group.

And speaking of solar events, if you think radiation is not something connected to our subject of evolution, you're bonkers.

However, in defining evolution, I don't list influences that affect rate of mutation, rate of evolution, or kind of evolution. To do so is a mistake.

You would transform any definition back to a "Hymn To Allele". And that is not what you want, is it ?

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@memester,

memester;121768 wrote:

it's all encompassing, if that is what you mean.
and why can they not be included ?

But all encompassing is not useful if it's too much. If your definition of human is "an animal", that would be all encompassing but it would fail to define.

memester;121768 wrote:

Not only do I take that into account, but I also acknowledge what you do not even glimpse - that it is included precisely because we do not know what is at work.

I glimpse that just fine, and I'll overlook yet another puerile dig from you.

I believe that. I acknowledge that. I glimpse it just fine. But evolution would describe the change in shaving behavior over time, not the change in my personal facial hair over time.

memester;121768 wrote:

You would transform any definition back to a "Hymn To Allele". And that is not what you want, is it ?

You keep missing the fact that I acknowledge several times in this thread that my allele definition was too restrictive.

Your epithets, digs, labels, and overall childish attitude are getting us nowhere but to bicker rather than discuss.

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@jeeprs,

jeeprs;121703 wrote:

well what about the Cambrian Explosion, eh? That put a cat amongst the pterodactyls, even in Darwin's day:

It is possibly history's greatest example of punctuated equilibrium.

However, I think it's significance as a period during which so much occured is overstated.

54,000,000 years is a decent amount of time. It's amongst the largest of the Phanerozoic Periods (bear in mind that in Darwin's day these periods were not measured radiometrically - and were thought to be much shorter than we now think they are).

The driving force for the diversification of life during this period probably derived from a single biological paradigm shift - multicellularity.

We tend to think on the multicellular scale - so earlier paradigm shifts (such as the symbiosis of single-celled life producing mitocondria and other organelles) tends not to excite our imaginations so much.

Once you have that shift to multicellular options for life - I think it's easy to see that the diversification of form as a result could be relatively dramatic - as it opens up so many new niches to be exploited (including new niches for single-celled parasites within multicellular organisms themselves).

But just because a number of major phyla occur in the same period (of fifty million years) isn't a problem for the core concept - at some point major branches leave the trunk of a tree - here's where it happens on the tree of life.

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@Aedes,

Aedes;121770 wrote:

But all encompassing is not useful if it's too much.

Of course, but it's not too much, it just makes it. A perfect fit.

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If your definition of human is "an animal", that would be all encompassing but it would fail to define.

no, you, the cultural descendant of Linnaeus, merely demand more homage to him. that's fine. do it on your own dime.

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But evolution would describe the change in shaving behavior over time, not the change in my personal facial hair over time.

Evolution would not describe anything. I could describe the evolution of your facial hair, the evolution of shaving habits, the evolution of HIV as it relates to sharing tools, I could describe ten thousand things that are evolving. What your shaved face can be, is a phenotype. And that will change over time.

BTW...your growth of beard...you didn't have it when you were 5, did you ?
What was the heritability of beardedness in your kindergarten class, you figure ? Eh ? whassat ?

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You keep missing the fact that I acknowledge several times in this thread that my allele definition was too restrictive.

and yet you talk about heritablilty again.

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@memester,

memester wrote:

and yet you talk about heritablilty again.

He may find your definition too expansive and his definition too restrictive, but he still feels that evolution has to do with heritability; at the least, there has to be something which seperates evolution from being considered every change.

I see your point, though - how do we know every thing doesn't effect our evolutionary pattern in some way. But how far down the rabbit hole do you really want to go? Do you really want to claim everything that happens to an organism is evolution?

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@memester,

memester;121776 wrote:

Of course, but it's not too much, it just makes it. A perfect fit.

I disagree, I think evolution MUST be defined by heritable biologic change. Insofar as acquired things may influence and be influenced by heritable factors, this can go into an elaboration on its definition -- it's certainly central to the concept. Perhaps we are erring by trying to restrict the definition to one sentence.

memester;121776 wrote:

no, you, the cultural descendant of Linnaeus, merely demand more homage to him. that's fine. do it on your own dime.

Again, what is with your obsession with calling names and picking labels? Are you adult enough to have a conversation without it?

memester;121776 wrote:

and yet you talk about heritablilty again.

1) alleles are insufficient to completely encompass heritable elements

2) I'm talking about it again because I completely disagree with your definition of evolution for lack of inclusion of heritability

So it boils down to our disagreement as to whether a definition of evolution MUST specify heritability or not. If you disagree that it must, then I'm not going to waste my time talking about alleles since you are not interested in heritability as a necessary feature of evolution.

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@Aedes,

Aedes;121783 wrote:

Are you adult enough to have a conversation without it?

Clearly not.

Why not moderate the troll and have scientific debates return to a semblance of straight talking and decent exchange of opinions and ideas?

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@Dave Allen,

Dave Allen;121784 wrote:

Why not moderate the troll and have scientific debates return to a semblance of straight talking and decent exchange of opinions and ideas?

People hang themselves eventually if they continue to troll, I don't need to do the culling. Besides, I think beneath the terrible social skills there is an interesting conversation to be had. I'm willing to wait a couple more posts to decide.

1 Reply

Definition of evolution

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