Darwin re-visited

[Michaelangelica]

Look all I have been trying to say is the 1859 Darwinian theory of " 'Natural' Selection" needs a bit of tweaking in view of the advances in genetics and biology.

 

It is a logical circular argument that is impossible to disprove.

 

A plant with a human-designed weedicide resistance does not seem 'natural' to me.

 

According to Kimura, when one compares the genomes of existing species, the vast majority of molecular differences are selectively "neutral."

That is, the molecular changes represented by these differences do not influence the fitness of the individual organism.

As a result, the theory regards these genomic features as neither subject to, nor explicable by, natural selection.

This view is based in part on the degenerate genetic code, in which sequences of three nucleotides (codons) may differ and yet encode the same amino acid (GCC and GCA both encode alanine, for example). Consequently, many potential single-nucleotide changes are in effect "silent" or "unexpressed"

. . .

Through drift, these new alleles may become more common within the population.

They may subsequently be lost, or in rare cases they may become "fixed"--meaning that their substitution becomes a 'permanent' feature of the population.

When an allele carrying a new substitution becomes fixed, the effect is to add a new allele to the population. In this way, neutral substitutions tend to accumulate, and genomes tend to evolve.

Neutral theory of molecular evolution - Wikipedia, the free encyclopedia

SEE also

Molecular evolution - Wikipedia, the free encyclopedia

[Rade]

Look all I have been trying to say is the 1859 Darwinian theory of " 'Natural' Selection" needs a bit of tweaking in view of the advances in genetics and biology.It is a logical circular argument that is impossible to disprove.

OK, now I understand. Well, if that is all you have been trying to say--if that is the motivation for the thread topic titled "Darwin Re-Visited"--then all I can tell you is that the 1859 concept of natural selection of Darwin has been significantly tweaked over the past 100 years. Darwin has been re-visited so many times there is a well worn path to his door. Take a look at the past 30 year history of papers published in a single journal called "Evolution"--what you will learn if you take the time to read these papers is a recent history of the tweaking you seek. As example, your most recent post of neutral allele hypothesis of Kimura, is an important part of the tweaking of natural selection that has been going on.

 

a plant with a human-designed weedicide resistance does not seem 'natural' to me.

Well, it does to me. We will just have to agree that we start from different philosophic bents on the "nature" of Homo sapiens.

 

I find this thread topic to be asked and answered, have a good day.

[HydrogenBond]

The theory of natural selection implies that nature does not always give selective advantage to the best genes. Selective advantage can go to lessor genes, which is the main source of confusion.

 

The easiest example to see is the period of time when dinosaurs and mammals were both on earth. Relative to the genetics, the mammals were higher in evolution. But the dinosaurs had the selective advantage, until the environment changed, then mammal genetics was able to better equate with selective advantage.

 

Here is another example. If we took the current king of the beasts or lion, his genetics are very modern. If we had a cage match with T-rex, the former king of the beasts, with his out-dated primative genetics, compared to the modern lion, who would have the selective advantage? I would bet the farm, T-rex will win the bout.

 

Relative to pandemics, it is inconclusive whether natural selection will pick the better genes or not. Natural selection may be based on a single gene or two instead of all the DNA. Natural selection doesn't really tell much with respect to the entire content of the DNA.

 

Relative to T-rex and the lion, rather than a cage match, we will have them compete at something that requires more advanced genetics. We can set up an obstacle course to get the advanced brain genetics involved. Now the selective advantage would go to the lion. This is the problem with selective advantage, it allows one to stack the deck and get any result you want, since it only has to equate one gene to appear like it is right. The smoke and mirrors is this one gene being pitched as genetics.

 

Natural selection and selective advantage is a theory where one can cheat and win. For example, we have two twins with the same genetics, except one variation, that makes one twin faster at running. So we have a race. If we want the slower twin to have the selective advantage, we tell him to trip its brother. This will then give him the selective advantage, i.e., survival of the fittest.

[Michaelangelica]

Losses of long-established genes contribute to human evolution

Losses of long-established genes contribute to human evolution

While it is well understood that the evolution of new genes leads to adaptations that help species survive, gene loss may also afford a selective advantage.

 

Human evolution in genetic fast lane

Human evolution in genetic fast lane

Countering a common theory that human evolution has slowed to a crawl or even stopped in modern humans, a new study examining data from an international genomics project describes the past 40,000 years as a time of supercharged evolutionary change, driven by exponential population growth and cultural shifts.

 

More regulatory DNA that previously thought

More regulatory DNA than previously thought

Surrounding the small islands of genes within the human genome is a vast sea of mysterious DNA. While most of this non-coding DNA is junk, some of it is used to help genes turn on and off.

 

Genetic animal model of autism]

Genetic animal model of autism

By introducing a gene mutation in mice, investigators have created what they believe to be the first accurate model of autism not associated with a broader neuropsychiatric syndrome, according to research presented at the American College of Neuropsychopharmacology annual meeting.

 

Tuberculosis found in 500,000-year-old human

Tuberculosis found in 500,000-year-old human

Although most scientists believe tuberculosis emerged only several thousand years ago, new research from The University of Texas at Austin reveals the most ancient evidence of the disease has been found in a 500,000-year-old human fossil from Turkey.

 

(So it tuberculosis in the slow lane? If so how come we are not winning?)

 

 

Thanks to

News-Medical.Net (AZoM.com Pty.Ltd.)

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90 Mona Vale Road

Mona Vale

Sydney

NSW, 2103

Australia

 

Tel: Direct +61 2 9999 0070

e-mail: [email protected]

[HydrogenBond]

Here is another evolutionary angle. If you look at a herd of animals in an integrated ecosystem, natural design has the predators seeking out the weak as a food source. From a practical point of view, these represent the easiest targets with the highest rate of success. Relative to genetics, this also removes genetic variations from the herd that don't represent forward progress.

 

Relative to modern humans, we go about this in a different way. The weak and sickly get a large share of resources. It is sort of analogous to the weak in the herd getting extra protection so they can survive and breed. From a moral point of view, this is the right thing to do. But from a genetic point of view does it optimize the progression of genetics? Or does it cause humans genetics to stagnate or regress?

 

I am not condoning anything but only comparing natural selection to what humans do, which does not follow the natural rules. For example, say we had a herd of deer. In the natural environment, the wolves get the sick. With humans we change the rules of the game and protect the sick. In nature, the dominate male breeds, so even if the sickly males were artificially protected, this fail safe assures that the best genes. But with humans, there is somebody for everyone, such that anyone can breed. In terms of the female herd animals, good genetics is needed to assure their young will be born and can be nurtured and protected, such that even if the sick and weak females were protected, this fail safe would still favor forward genetic progress. But with humans, we can artificially allow the sick females to breed and propagate, by protecting the weak system.

 

From a moral point of view this is the right thing to do. But from a purely objective natural selection point of view, it is not optimized. One possible way to explain this is that what we are optimizing is an aspect of humans that is outside of genetics.

 

An analogy is AI (artificial intelligence). The most important thing for such a futuristic system is not hardware (genetics) but programming. One can have a better computer but if the programming is off, than the AI may be sort of an illusion. On the other hand, good programming with a lessor computer system, which allows AI, is a more advanced composite. Ideally one would want the best computer to have the best programming, but in the end whatever allows the human AI to appear, is what is optimized.

[Pyrotex]

[reposted from "Humans stop evolving?"]

 

Evolution's survival of the fittest cannot be avoided. The only thing that changes is the definition of "fit".

If cattle are being bred for large roasts, then having a large roast makes an individual steer "fit".

If men and women are being "selected" for their ability to recognize and return love, then those abilities make the individuals "fit".

 

You cannot, even in principal, avoid biological evolution. All you can do is modify some of the definitions of "fit". And not even ALL of those.

 

WHATEVER reason two humans come together and make a baby... love, lust, opportunity, beer, calculated self-interest, bad habits, extortion, carelessness, curiosity... then THAT is what is being selected for in that instance, and THAT reason is the current definition of "fit" for that couple.

 

Lots of these "random" definitions for "fit" will cancel out in the big picture, when you're looking at thousands or millions of couples in a community, nation, culture, world.

 

But even world-culture cannot cancel out everything. People at the world level, overall, are still being "bred" as a result of their "fitness" for something. It may be physical fitness, beauty, charm, wealth, good doctors or a propensity for being at the right place at the right time.

 

The chief point here is that two humans got together for SOME reason and had a baby. For THAT couple, "fitness" is whatever the heck brought them together. And their baby has a slight statistical improvement in its "fitness"--whatever it is for that particular coupling. This is just the way that sex works in all plants and animals on Earth. Whatever that has DNA and two genders.

 

"Fit" calls into question an "environment" in which to BE fit. Right? Well, our "environment" includes things that monkeys, horses, spanish moss, and dragonflies cannot have: a culture, predicated on intelligence, self-awareness, language and technology.

 

So, in Darwin's statement about survival of the fittest, when you look at humans, you have to redefine "fit" and "environment", that's all.

[Michaelangelica]

Relative to modern humans, we go about this in a different way. The weak and sickly get a large share of resources. It is sort of analogous to the weak in the herd getting extra protection so they can survive and breed. From a moral point of view, this is the right thing to do. But from a genetic point of view does it optimize the progression of genetics? Or does it cause humans genetics to stagnate or regress?

I'm with HB on this.

It seems to me that to re-define our definition of 'fit' to include those who would previously died is shoe-horning Darwin's arguments. It is a circular argument same as 'environment' and 'natural selection' You can make these words fit any definition you like, not just a genetic one.

'Circular Arguments' from 'Clear Thinking'

[Pyrotex]

hmmmm. You seem to think thats evolution has a particular definition of "fit" programmed into it. Evolution "knows" which attributes are part of "fitness" and which aren't. Wow. Evolution must be pretty smart.

 

Well actually, evolution is as stupid as a fence post. Let's use artificial selection as a starting point. Joe Farmer is breeding cows with black hides--or, that's what he thinks he is doing. He selects only those cows and bulls whose hides are darker, and allows only those to mate. Whether or not Joe succeeds is immaterial. The browner and redder cattle do not get to mate.

 

What happens is that darker cattle get to procreate and lighter ones don't. What does "fitness" mean in this context? Fitness means having a dark coat. Period. Joe doesn't care about muscles, size, or speed. Just color. Being dark is the ONLY way you get to breed and pass your genes on to the next generation.

 

But what if Joe wants miniature cattle and breeds for that? Well, "fitness" means being smaller--because that is the ONLY way you get to breed and pass your genes on to the next generation.

 

And THAT is where you should be looking. "Fitness" is whatever attribute that increases your chance of breeding and passing your genes on to the next generation. Saying that evolution only looks at physical strength or health as "fit" is applying an artificial and human biased definition on "fit".

 

Out in the wild, or whatever environment an animal (or human) finds itself in, "fitness" is whatever attributes that increases its chance of breeding and passing its genes on to the next generation. THAT is the ONLY definition of "fit" that has any meaning to evolution.

[Michaelangelica]

hmmmm. You seem to think thats evolution has a particular definition of "fit" programmed into it. Evolution "knows" which attributes are part of "fitness" and which aren't. Wow. Evolution must be pretty smart..

No, i think people have a particular and very fluid, and changeable idea of 'fit'

 

And try not to condescend to me.

 

No matter what happens "natural selection' and "fit" can be adapted to any situation. There is no way anyone can disprove any of this because it ebbs and flows like putty. It is logically fallacious.

[Michaelangelica]

What are the implications of this research to Natural Selection?

Epigenetics May Be The Underlying Cause For Male Infertility

 

ScienceDaily (Dec. 13, 2007) — Researchers at the University of Southern California (USC) suggest epigenetics, or the way DNA is processed and expressed, may be the underlying cause for male infertility.

. . .

n the United States, about 4 million married couples of child-bearing age are infertile and in approximately 40 percent of the cases, the infertile partner is the man

. . .

Attention is now focused on epigenetic changes. Epigenetic change, which is defined as in addition to changes in genetic sequence, includes any process that alters gene activity without changing the DNA sequence. Some of these epigenetic changes are inherited from one generation to the next.

. . .

sperm DNA from men with low sperm counts or abnormal sperm had high levels of methylation, which is one of the ways the body regulates gene expression.

Epigenetics May Be The Underlying Cause For Male Infertility

[Pyrotex]

No, i think people have a particular and very fluid, and changeable idea of 'fit'

 

And try not to condescend to me.

 

No matter what happens "natural selection' and "fit" can be adapted to any situation. There is no way anyone can disprove any of this because it ebbs and flows like putty. It is logically fallacious.

Didn't mean to be condesscending. My posting style is just kinda loose and chatty. Sounds less aggressive that way, I think.

 

Darwin himself defined "fit" and "fitness" in [Origin of Species]. This is not somethiing that is fluid and changeable. Fitness is whatever attributes increases the probability of reproducing and passing on genes to the following generations. Very simple and straightforward. That's how Darwin defined it, not me. And if you think about it, that's the ONLY way that evolution CAN work.

 

Merry Christmas

[Michaelangelica]

Prof Paul Ehrlich rides again

Thursday 20 December 2007

 

Listen Now - 20122007 | Download Audio - 20122007

Paul Ehrlich Part Two

 

The second half of Paul Ehrlich's coruscating address to the Ecological Society of Australia meeting in Perth. Why does Australia lead the world in ecological science? What does he think of George Bush and John Howard? Why does President Bush ask how "our oil got under THEIR sand?" Read Transcript

Thursday 13 December 2007

 

Listen Now - 13122007 | Download Audio - 13122007

Prof Paul Ehrlich rides again

 

His book The Population Bomb exploded in 1968, making him one of the pioneers of environmental concern. Paul Ehrlich, Professor of Biology at Stanford University (California), is an ecologist who comes to Australia to study our birds and butterflies. But he still talks explosively on green questions, as he did in Perth at the Ecological Society of Australia conference. He had a 'conversation' with 600 delegates, strolling, without notes, on stage. His message is undiminished by his age - 75 years and still outspoken. Read Transcript

 

 

It was again - and I'll be really controversial, we saw in a very nice talk by the science minister a couple of minutes ago one of the results of what I like to call Darwin's mistake.

What was Darwin's mistake?

I am possibly the world's greatest fan of Darwin but he didn't do absolutely everything right, and one of his biggest mistakes was to name his classic book, which I have now read three times, On the Origin of Species, which should have been On the Differentiation of Populations. By putting the emphasis on species, first of all he supplied employment for a lot of otherwise unemployable people who work as taxonomists and argue forever over what is a species.

This would be the equivalent of people in geology saying: if you want to understand erogeny you have to be able to define a mountain, and so the issue is, what is really a mountain...and you can think about that for a while.

 

But worse than that, it's pushed all of our attention, the public's attention particularly, and we have an example here of conservation of biodiversity onto conserving species, you don't want the species to go extinct.

 

Well do a little thought experiment, let's imagine somehow miraculously we could preserve every species on the planet by waving a magic wand as a single viable population forever. There would be no further loss of species diversity and of course we'd all soon be dead because we can't get along on just one viable population of each species like rice, wheat and so on but all the other things.

 

If you think about it you can see it's preposterous. What we have to have is a vast diversity of populations everywhere to supply the eco system services upon which our society absolutely depends.

 

And yet when did you last hear anybody standing up, besides me and a very few other colleagues maybe, getting up and saying we've got to preserve populations.

You know in the United States today we are in trouble for pollinators, it's not because Apis mellifera no longer exists on the planet, it's just that there's so many fewer of them than there used to be and most of the native pollinators that could have substituted for them are now extinct because of habitat loss.

 

So we have this incredible problem of the loss of biological diversity particularly at the population level, much more serious that loss of diversity at the species level, that basically goes ignored.

 

In Conversation - 13 December 2007 - Prof Paul Ehrlich rides again

In Conversation

[Michaelangelica]

Darwin himself defined "fit" and "fitness" in [Origin of Species]. This is not somethiing that is fluid and changeable. Fitness is whatever attributes increases the probability of reproducing and passing on genes to the following generations. Very simple and straightforward. That's how Darwin defined it, not me. And if you think about it, that's the ONLY way that evolution CAN work.

You can accept or reject these particular evolutionary explanations as you like. But the underlying message is worth taking home: Much of what now passes for "natural selection" isn't exactly natural. It's social.

As such, it deserves no presumptive respect as a validator or promulgator of objective fitness.

Nor does the discovery of a genetic basis for this or that trait prove it's more than a social construct. In the era of cultural selection, many genes are a social construct. Which makes them no less real.

The evolution of evolution. - By William Saletan - Slate Magazine

[freeztar]

Hey M, I'm curious why you quoted Pyro before posting the article quote. Was it meant to be a refutation of what Pyro posted?

[Pyrotex]

Hey M, I'm curious why you quoted Pyro before posting the article quote. Was it meant to be a refutation of what Pyro posted?

oh, please, god, don't let him refute me!

Please!!!

PLEEEZE!!!! :doh:

[Michaelangelica]

oh, please, god, don't let him refute me!

Please!!!

PLEEEZE!!!! :shade:

Yes of course. (!)

My role here is to make the lives of moderators miserable :shrug:

 

I don't like the "post-hoc" logic of natural selection.

 

I suspect there is much more to evolution than we know. We seem to have a closed mind on the subject, partly as a result of silly Darwinian criticism.

 

I see new science all the time suggesting (but not quite getting there) that Darwin was only part-right.

 

When I see bits of science that do that (above) I post them here to annoy everybody and confuse the creationists.(Who have no idea where I am coming from)

:hyper:

Unfortunately I am not intelligent enough to make a clear,concise and coherent argument for something that I only vaguely feel is not wrong, but not quite right.

[freeztar]

Yes of course. (!)

My role here is to make the lives of moderators miserable :shrug:

 

And we'll reciprocate with pleasure. :hyper:

(not really, but it sounded good :shade: )

 

I don't like the "post-hoc" logic of natural selection.

What are you referring to specifically?

I suspect there is much more to evolution than we know. We seem to have a closed mind on the subject, partly as a result of silly Darwinian criticism.

Who is we? "Silly Darwinian criticism" sounds like a closed mind to me.

 

I see new science all the time suggesting (but not quite getting there) that Darwin was only part-right.

Like?

 

When I see bits of science that do that (above) I post them here to annoy everybody and confuse the creationists.(Who have no idea where I am coming from)

:)

 

The article you last posted was in favor of Darwin, which seems off, given your last statement.

 

Unfortunately I am not intelligent enough to make a clear,concise and coherent argument for something that I only vaguely feel is not wrong, but not quite right.

 

I think you are intelligent enough Mich. :)

Knowledge seems to be a history of ladders. We'll hold 'er for you mate. ;)