The origins of humanity/ evolution (with spoilers for the movie PROMETHEUS)

The problem I have with that is the timescale. The first life on Earth is dated 3-4 billion years ago- an unimaginable span of time. I can't accept that these humanoids have survived unchanged (much less hung around) for countless epocs all just to mess about with Earth and its ape civilisation. Earth is a speck- and any species that ancient would be lords of the galaxy if not omnipotent.

If humans were an accidental byproduct of their experiments- then it would be impossible for us to have the same gene sequence. Random mutations and selction pressures change organisms in a trillion different ways over billions of years. As has been said by biologists, if you were to re-set evolution from day 1, even if conditions were identical, we would have an entirely different eco-system and completely different range of species. We may not even get vertebrate life on a second run (bone has only evolved once on Earth).
As I say, I haven't seen the film, but am I right in thinking that the basic premise is that one or more human aliens dissolved themselves in the sea of an unnamed planet, presumed to be Earth, and this resulted in the development of humans on that planet some unidentified time later? The two possibilities seem to be either this was the first DNA on the planet, which kickstarted life and eventually produced humans; or the planet already had life and this new DNA exploited that, perhaps by hybridizing with primates, to produce humans.

If so, then as you say there is no way that evolutionary theory could account for it. But I have suggested a few SF-type ways in which it might be done. My favourite, which seems to have no logical holes in an SF context, is a time-travelling alien who creates a closed-time loop. Life got started because someone went back to start it. It's like the guy who went back in time, accidentally killed the young Will Shakespeare and had to write the plays himself. It needs a deterministic Universe, but I have no problem with that.
 
Your first point is correct, but the film seems to miss the point that (a) every human who has ever lived has had a unique genome; (b) so to define an entity as human from its genome is simply applying a statistical probability.

Your second point applies equally to Earthly human races, so it doesn't seem contradictory to me.

Of course. What I meant was the creatures are very clearly humanoid, (which gives the film a whole anthromorphic feel that has never sat well with me in SF generally). Yet, they are also very clearly a seperate species to homo-sapiens, with physiological differences that are greater than, say, the difference between a homo-sapien and a homo-erectus. So the way a little computer screen chirpily announces 'DNA 100% Match!' in hokey SF style struck me as a little silly.
 
As I say, I haven't seen the film, but am I right in thinking that the basic premise is that one or more human aliens dissolved themselves in the sea of an unnamed planet, presumed to be Earth, and this resulted in the development of humans on that planet some unidentified time later? The two possibilities seem to be either this was the first DNA on the planet, which kickstarted life and eventually produced humans; or the planet already had life and this new DNA exploited that, perhaps by hybridizing with primates, to produce humans.

Correct. But it isn't made clear which of the two scenarios is supposed to be playing out. I'd be more comfortable with the latter.

If so, then as you say there is no way that evolutionary theory could account for it. But I have suggested a few SF-type ways in which it might be done. My favourite, which seems to have no logical holes in an SF context, is a time-travelling alien who creates a closed-time loop. Life got started because someone went back to start it. It's like the guy who went back in time, accidentally killed the young Will Shakespeare and had to write the plays himself. It needs a deterministic Universe, but I have no problem with that.

That makes more sense than the film does! But in this movie (sequels are implied) there is no hint of any time-travel element.
 
lucas, clear out your PMs please. :)
 
The problem I have with that is the timescale. The first life on Earth is dated 3-4 billion years ago- an unimaginable span of time. I can't accept that these humanoids have survived unchanged (much less hung around) for countless epocs all just to mess about with Earth and its ape civilisation. Earth is a speck- and any species that ancient would be lords of the galaxy if not omnipotent.

If humans were an accidental byproduct of their experiments- then it would be impossible for us to have the same gene sequence. Random mutations and selction pressures change organisms in a trillion different ways over billions of years. As has been said by biologists, if you were to re-set evolution from day 1, even if conditions were identical, we would have an entirely different eco-system and completely different range of species. We may not even get vertebrate life on a second run (bone has only evolved once on Earth).

Fair point.....I guess it is possible if they are time travellers, as I think it has been suggested, have some form of hibernation cycle, or are themselves a tool of a higher being.....but, of course, these are all massive assumptions to try and justify the plot hole......unless Scott has then answer ready for part-2...... I'll look forward to an answer then! :lease::D
 
I thought natural selection, selects. Resulting in specialization but reducing genetic diverisity....
No. It produces a huge number of forms, demonstrating a vast range of degrees of specialisation. Its whole driving force is an increase in genetic diversity.
 
No. It produces a huge number of forms, demonstrating a vast range of degrees of specialisation. Its whole driving force is an increase in genetic diversity.

I thought it selects. As in it does not create the original genetic variation from which it is selecting creating specialisation. That natural selection on it's own does not add new genetic information, abilities that are not present. The variation has to either be there originaly, occur via mutation, etc... That natural selection on it's own is not a full explaination. That hisorically there may have been periods of mass mutation creating a wide range of life.
 
I thought it selects. As in it does not create the original genetic variation from which it is selecting creating specialisation. That natural selection on it's own does not add new genetic information, abilities that are not present. The variation has to either be there originaly, occur via mutation, etc... That natural selection on it's own is not a full explaination. That hisorically there may have been periods of mass mutation creating a wide range of life.

Natural selection isn't some 'tangible force' that acts on organisms- its just a descriptive term for the survival of succesful lifeforms over unsuccesful ones. Mutation is what alters the organism (or rather the species) during reproduction. Mutation always occurs whenever DNA is replicated because it is never copied exactly (thats why DNA can be used to identify an individual person). If the mutation is of any benefit to the organism in it's given environment, it will be passed to the next generation. If it is detrimental, the organism is less likely to survive to pass on its genes- so it doesnt get passed on. Natural selection.

Variation depends not just on the mutations themselves but on the selection pressures bearing on the creature. There are near infinite selection pressures and a near infinite amount of possible mutations- so obviously there is scope for a staggering variation of possible life forms given the right amount of geological time.
 
I thought it selects. As in it does not create the original genetic variation from which it is selecting creating specialisation. That natural selection on it's own does not add new genetic information, abilities that are not present. The variation has to either be there originaly, occur via mutation, etc... That natural selection on it's own is not a full explaination. That hisorically there may have been periods of mass mutation creating a wide range of life.
No, you're quite right. Perhaps my first answer was a little too glib. lucasasking has explained it well, but I'll add my two-penn'orth.

Natural selection will tend to create specialisation if left alone. What I mean is, if an animal finds itself in an environment which is unchanging and undemanding over many thousands of years, then it's possible that any mutation will tend to be harmful and not selected, except perhaps those which make the animal even better adapted to that environment. This will increase specialisation and reduce genetic diversity. Good examples are the giant panda and the koala, which by any criterion are evolutionary failures. Any change in their environment finds them unable to adapt.

But the point is, such environments are very rare, and natural selection has proven supremely powerful in creating organisms which can exploit the changes. Take say the cheetah, which has specialised in running down fast prey. What we have there is not a static environment, but a constantly changing one, where the prey get ever faster, forcing the cheetah to improve its own skills. This is called an arms race. But the cheetah doesn't have to run after prey: it does it because it can, but it will quite happily take anything which comes its way. So if for some reason fast prey suddenly vanished, it's quite possible the cheetah will survive.

On the other side, natural selection also produces generalists; organisms which can adapt their behaviour to a wide variety of habitats without necessarily becoming new species. In mammals, humans have become the generalists supreme.

Now look at genetic diversity. Diversity arises from mutations, which natural selection works on. Any species is a mix of mutations, most of which are beneficial in some respects, but possibly harmful in others. Many others are neither harmful nor beneficial at any given time, and they tend to hang on in the genetic makeup. But given a change in circumstances, it may be that a previously neutral or even harmful mutation suddenly becomes beneficial, and allow its owner to continue to flourish. A classic example are peppered moths, which were mostly white until the industrial revolution turned many of their resting places black with soot. Suddenly, literally almost overnight, black moths started to appear and become the majority in the population. Then, after the clean up of the 20th century, the white ones picked up again.

Genetic diversity is a measure of the number of variations of any given gene which are present across a species at any time. The more there are, the better that species will adapt to change. The fewer, the less able it is to do so. Pandas and koalas are not very diverse.

That's what I meant by saying natural selection creates diversity. Perhaps I should have said that it encourages it, giving it more to work on. Hence, the more diverse an organism is, the better it will survive.
 
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Alien was first class SF (mind you, Alan Dean Foster is a first class SF writer).

Alan Dean Foster didn't write the screenplay for Alien, he merely adapted the screenplay for the novelization that came after the movie.
 
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I haven't seen the film or know much about it, but I do know a little about this sort of thing, I think panspermia is a plausible idea, however I think it is highly highly unlikely and to an extent only pushes the problem back to how did the aliens first evolve. If life did begin in this fashion it would be through the deposition of organic matter (such as amino acids, nucleotides that make up DNA, etc..) rather than whole sections of DNA, this DNA would be of no use without the machinery that "reads" the DNA and then makes what is needed from it.

The most widely believed theories for the origins of life are an RNA world, in which molecules very very similar to DNA first formed which could catalyse further reactions and essentially replicate themselves (the non philosophical definition of life is pretty much the ability for something to replicate itself), or the iron sulphide world in which it is believed that simple cycling chemical reactions became self sustaining (and no longer needed the environment to drive them, eg deep sea vents were are thought to have provided a possible source for the "building blocks" of life") and these chemical reactions led to the production of nucleic acids which make up DNA/RNA. Experiments that replicate the conditions that would have been present about 3 billion years ago have shown that the vast majority of chemicals essential for the beginning of life could of all occurred naturally, and there is evidence for both theories.

More info on them can be found here:
RNA world hypothesis - Wikipedia, the free encyclopedia
Iron

If anyone is interested, I might be able to point you in the direction of some papers on such ideas (although they aren't as simple reading as wikipedia :rolleyes:), also I would recommend this book:Life Ascending: The Ten Great Inventions of Evolution: Amazon.co.uk: Nick Lane: Books
The first chapter is a good (aimed at the man on the street) discussion of such theories, and the rest of the book is certainly very interesting for anyone with an interest in evolution/biology.

:smashin:
 
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Mutation is what alters the organism (or rather the species) during reproduction. Mutation always occurs whenever DNA is replicated because it is never copied exactly (thats why DNA can be used to identify an individual person). If the mutation is of any benefit to the organism in it's given environment, it will be passed to the next generation. If it is detrimental, the organism is less likely to survive to pass on its genes- so it doesnt get passed on. Natural selection.

Now look at genetic diversity. Diversity arises from mutations, which natural selection works on.

But while natural selection that reduces genetic diversity via specialization is proven and occurring now.

What evidence is there that positive genetic mutation is occurring now. That new beneficial traits and abilities due to new genetic information via mutation are occurring as a slow natural process of evolution.

I was under the impression that historically there may have been periods of sudden mass mutation, but that the evidence is historic in fossils. That there is a lack of evidence of positive mutation evolution of new increased genetic information, new traits and abilities, occurring now as a slow continual evolutionary process. Am I mistaken? Is there proof of it occurring now?

I was under the impression that mutation now seems to be harmful, genetic damage, faults. Not beneficial.

A classic example are peppered moths, which were mostly white until the industrial revolution turned many of their resting places black with soot. Suddenly, literally almost overnight, black moths started to appear and become the majority in the population. Then, after the clean up of the 20th century, the white ones picked up again.

It is a example of increased genetic diversity? Did the black moths appear out of nowhere the result of new genetic information via mutation?
Or does it simply prove changes in frequency of different types in the moth population. So at best pointing towards natural selection reduced genetic diversity.

Also is not Kettlewell's peppered moths example and experimental proof known to be very flawed as far as verifying it as very advantageous and the level of data on moth populations, and the supporting photographic proof known to be fabrication to exagerate the findings and reinforce the conclusions.
 
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But while natural selection that reduces genetic diversity via specialization is proven and occurring now.

What evidence is there that positive genetic mutation is occurring now. That new beneficial traits and abilities due to new genetic information via mutation are occurring as a slow natural process of evolution.
Mutations in DNA are observed and easy to spot. There is no such thing as a 'beneficial' or 'harmful' mutation except in the context in which it works. They are not a 'slow natural process of evolution'. A random mutation may have one of three effects:
  • It reduces its owner's ability to survive long enough to reproduce. In that case, it will probably be lost;
  • It enhances that ability. If so, it will spread because its owner will in general have more offspring than average;
  • It has no effect. Then it will sit in the genome unless and until it either becomes useful or is lost.
I was under the impression that historically there may have been periods of sudden mass mutation, but that the evidence is historic in fossils. That there is a lack of evidence of positive mutation evolution of new increased genetic information, new traits and abilities, occurring now as a slow continual evolutionary process. Am I mistaken? Is there proof of it occurring now?
No, that impression is quite mistaken. There may have been periods of increased mutation, but it is known that they occur spontaneously at a known average rate, and that rate seems to have been pretty constant throughout history. There do seem however to have been periods of increased evolutionary change (the Punctuated Equilibrium theory), but that is put down to increased environmental pressures, not mutation rates.
I was under the impression that mutation now seems to be harmful, genetic damage, faults. Not beneficial.
No. Absolutely not.
It is a example of increased genetic diversity? Did the black moths appear out of nowhere the result of new genetic information via mutation?
Or does it simply prove changes in frequency of different types in the moth population. So at best pointing towards natural selection reduced genetic diversity.
Looked at simply, there is a gene within the moth which determines its colour. In some individuals it's for white; in others for black. It probably arose originally because although their natural habitat favoured white, there were enough dark locations to allow a proportion of dark ones to persist. But as soon as the environment shifted to favour black, offspring of that colour were more likely to survive to adulthood, and hence become more common. But the white was not eliminated, any more than black was originally, so as things shifted yet again, the white colour re-established itself. TBH, I'm not sure where we are now with them. I suspect there are still more black moths around than there were before the 19th Century.

As for genetic diversity, that has remained unchanged throughout: it's a measure of the number of variations of a given gene there are, not the proportions of each. Again looking at it very simply, for this gene it's always been two.

All this can be treated quite rigorously with mathematics, and it turns out that it's quite difficult to eliminate a gene entirely, although it obviously does occur quite a lot. Natural selection does not eliminate diversity; it encourages it. But a species with low diversity will be subject to the perils of inability to adapt and of in-breeding, and may eliminate itself.
Also is not Kettlewell's peppered moths example and experimental proof known to be very flawed as far as verifying it as very advantageous, and the supporting photographic proof known to be fabrication to exagerate the findings and reinforce the conclusions.
Not to my knowledge. In any case, the moth is only one example of many similar ones, all of which demonstrate the ability of natural selection to wreak changes in populations over very small periods of time.
 
What evidence is there that positive genetic mutation is occurring now. That new beneficial traits and abilities due to new genetic information via mutation are occurring as a slow natural process of evolution.

I was under the impression that historically there may have been periods of sudden mass mutation, but that the evidence is historic in fossils. That there is a lack of evidence of positive mutation evolution of new increased genetic information, new traits and abilities, occurring now as a slow continual evolutionary process. Am I mistaken? Is there proof of it occurring now?

I was under the impression that mutation now seems to be harmful, genetic damage, faults. Not beneficial.

I might have interpreted what you say here wrong, but genetic mutations are still occurring at the same rate (this rate will vary between species based on the efficiency of their DNA repair and replication mechanisms) and also based on the presence of mutagens in the environment (ionising radiation etc) at the actual process of mutation there is no bias between whether a mutation is deleterious, advantageous or has no effect, it is only the interaction of that mutation with the current environment that determines that.

Large expansions in diversity that can be seen in the fossil record are the result of big changes in environment mainly, rather than a change to the type of mutation that occurs, such as a change to the atmosphere.

I think this is a good example of recent evolution that is due to a "positive" mutation: Natural Selection Favors a Newly Derived timeless Allele in Drosophila melanogaster Basically a single base change in the gene timeless in the fruit fly changes the protein ability to interact with others (genes are the code for making proteins, for anyone that doesn't know). TIMELESS is involved in judging how much light is present and therefore how long the days are. The mutation changing the protein reduces the amount of light the fly judges there to be, which basically results in the flies having an advantage at higher latitudes where day length and temperature and are seasonal. This "mutant" timeless makes it appear that there is less light than there is and causes the fly to go into a state of hibernation known as "diapause" earlier, which increases their ability to survive the winter.

The mutation originated in Southern Italy and has spread North, with the highest frequencies of the "mutant" found at higher latitudes.

Hope this makes sense, if not i'll try and explain more :thumbsup:
 
I think DPinBucks sums it up well, however I would disagree that natural selection doesn't eliminate diversity, although it certainly does increase diversity, it does eliminate it as well. Just think of all the millions of now extinct organisms that are simply extinct due to to being out competed or being ill adapted to an environment, these are both examples of natural selection. These represent a vast vast amount of all the genetic diversity that has ever existed on earth and yet this has all been eliminated by natural selection :)
 
Mutations in DNA are observed and easy to spot. There is no such thing as a 'beneficial' or 'harmful' mutation except in the context in which it works. They are not a 'slow natural process of evolution'. A random mutation may have one of three effects:
It reduces its owner's ability to survive long enough to reproduce. In that case, it will probably be lost;
It enhances that ability. If so, it will spread because its owner will in general have more offspring than average;
It has no effect. Then it will sit in the genome unless and until it either becomes useful or is lost.

I thought harmful mutations were the norm. We have lots of hereditary genetic disabilities and genetic disabilities caused by random mutation. Are there many or any identified hereditary beneficial mutations.

Are there any identified recent major beneficial genetic mutations of the kind that would be historically present in species gross changes, like sea creature evolves into land creature evolves in to flying creature, etc... Massive gross changes in form. Are these expected to be slow progressive changes small changes accumulating one on the other over time or sudden severe mutations.

I think this is a good example of recent evolution that is due to a "positive" mutation: Natural Selection Favors a Newly Derived timeless Allele in Drosophila melanogaster Basically a single base change in the gene timeless in the fruit fly changes the protein ability to interact with others (genes are the code for making proteins, for anyone that doesn't know). TIMELESS is involved in judging how much light is present and therefore how long the days are. The mutation changing the protein reduces the amount of light the fly judges there to be, which basically results in the flies having an advantage at higher latitudes where day length and temperature and are seasonal. This "mutant" timeless makes it appear that there is less light than there is and causes the fly to go into a state of hibernation known as "diapause" earlier, which increases their ability to survive the winter.

The mutation originated in Southern Italy and has spread North, with the highest frequencies of the "mutant" found at higher latitudes.

Thanks evidence of currently occurring positive genetic mutation resulting in evolution by natural selection was what I was under the impression was lacking. Are there lots of other examples of evolution in action due to beneficial mutation, as opposed to just natural selection specialization reduced genetic diversity.
 
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I think DPinBucks sums it up well, however I would disagree that natural selection doesn't eliminate diversity, although it certainly does increase diversity, it does eliminate it as well. Just think of all the millions of now extinct organisms that are simply extinct due to to being out competed or being ill adapted to an environment, these are both examples of natural selection. These represent a vast vast amount of all the genetic diversity that has ever existed on earth and yet this has all been eliminated by natural selection :)
OK, I'll buy that.

Actually, when I talked about genetic diversity, I meant within a species, ie average number of alleles per locus. You're including all those which have been eliminated, including entire species.

I think it's best to say that natural selection dynamically integrates genetic diversity and the environment to provide maximum replication in a given situation. The greater the diversity, the more it has to work on.
 
I thought harmful mutations were the norm. We have lots of hereditary genetic disabilities and genetic disabilities caused by random mutation. Are there many or any identified hereditary beneficial mutations.
I could name thousands, but I'll stick to one: the eye.

And there's the sickle cell gene, which benefits black people in hot climates, but leaves them vulnerable to anaemia. That's a good example of genetic balance.

Mutations are random. They are only harmful or beneficial in context. It's true that there are more harmful than beneficial mutations (actually, most seem to be neutral), but there are enough of the latter to keep natural selection going. And it's not black and white, anyway. It's a huge range of shades of grey. In general, a mutation either reduces or enhances an individual's chances of having offspring: it rarely eliminates it entirely and never makes it 100% certain. That's how it works: it's by statistical probabilities working out over a vast number of individuals.
Are there any identified recent major beneficial genetic mutations of the kind that would be historically present in species gross changes, like sea creature evolves into land creature evolves in to flying creature, etc... Massive gross changes in form. Are these expected to be slow progressive changes small changes accumulating one on the other over time or sudden severe mutations.
Yes. The most striking are domestic animals, which are now recognised to be separate species, especially dogs. Now I know you're going to argue that that that's not natural selection; it's selective breeding. But if you think about it, all that implies is that the environment has been created by humans: it's still natural selection which has produced the dog genome.

In the more 'natural' world, such developments are rarely seen, because although natural selection can work amazingly fast, it's rare for the environment to change drastically whilst still allowing its inhabitants to breed.
Thanks evidence of currently occurring positive genetic mutation resulting in evolution by natural selection was what I was under the impression was lacking. Are there lots of other examples of evolution in action due to beneficial mutation, as opposed to just natural selection specialization reduced genetic diversity.
I think the peppered moth is as good an example as any of what you're asking for.
 
I could name thousands, but I'll stick to one: the eye.

I was asking for evidence of genetic mutation creating new beneficial traits, in action as a ongoing process, rather than historic, fossils. I am pretty sure people I read about in history had eyes. That the evolution of eyes is not something we have witnessed happening as a ongoing process. While mutations causing genetic defects and disabilities are things we have seen happen, in action.

And there's the sickle cell gene, which benefits black people in hot climates, but leaves them vulnerable to anaemia. That's a good example of genetic balance.

I thought those with a single gene for sickle cell have a mutation in one gene that causes them to have defective blood cells, that the improved resistance to malaria was due to the pathogen being destroyed along with the persons own defective cells, that it is coincidentally beneficial side effect of a genetic fault.

Since those with two copies of the gene for sickle cell suffer a genetic disease that is devastating, I also find it hard to view as a genetic balance, rather than a genetic defect.

Mutations are random. They are only harmful or beneficial in context. It's true that there are more harmful than beneficial mutations (actually, most seem to be neutral), but there are enough of the latter to keep natural selection going.

Examples of the latter being seen in action are what I have been asking about. Because natural selection is proven it has been witnessed in action. But examples of positive genetic mutations, the increase in genetic variation new traits, needed for natural selection to select from, seem thin on the ground. As in proof it is a ongoing process rather than historic supported by fossil evidence. That is what I have been asking about.

The most striking are domestic animals, which are now recognised to be separate species, especially dogs. Now I know you're going to argue that that that's not natural selection; it's selective breeding. But if you think about it, all that implies is that the environment has been created by humans: it's still natural selection which has produced the dog genome.

I am not doubting natural selection has been seen and can be seen in action. It is the positive genetic mutations that are needed for natural selection to select from that I am asking about, as far as being seen in action as a currently occuring process.

Are you saying different breeds of dog have evolved new genetic information due to mutation and become divergent species. I guess if the various breeds of dogs were only fossils they would probably be viewed as different species of animal.

But I thought the breeds of dog were just evidence of selection, that the animals genome was capable of significant variation, just like with people lots of different shapes and sizes, that selective breeding could result in distinctive features, like difference in human ethnic groups or isolated population or groups who do not marry outsiders.

With the exception of small dogs being a product of a identified single gene genetic mutation, like people who have a genetic trait leading to being midgets or dwarfs. But not what I would view as a beneficial mutation.

That is I thought a dog is a dog and we have not managed to selectively breed a change that produces new traits, like the sea creature evolving into the land creature, or the land creature evolving into a flying creature, that all we have ever got from selective breeding dogs is dogs. Because we have been missing the ingredient of the beneficial genetic mutations creating new traits form which to select.

In the more 'natural' world, such developments are rarely seen, because although natural selection can work amazingly fast, it's rare for the environment to change drastically whilst still allowing its inhabitants to breed.I think the peppered moth is as good an example as any of what you're asking for.

The peppered moth is evidence supporting natural selection. It is not evidence of positive genetic mutation unless you are saying black is a new trait
 
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I was asking for evidence of genetic mutation creating new beneficial traits, in action as a ongoing process, rather than historic, fossils. I am pretty sure people I read about in history had eyes. That the evolution of eyes is not something we have witnessed happening as a ongoing process. While mutations causing genetic defects and disabilities are things we have seen happen, in action.
No they aren't. What makes you say so? A disability is not a mutation nor a genetic defect. It is simply an unfortunate expression of already existing genes. If you don't believe me, ask my HI grandson. His condition was not caused by a mutation: it was an unfortunate combination of the genes of my daughter and son-in-law.
I thought those with a single gene for sickle cell have a mutation in one gene that causes them to have defective blood cells, that the improved resistance to malaria was due to the pathogen being destroyed along with the persons own defective cells, that it is coincidentally beneficial side effect of a genetic fault.
Yes, exactly, except that 'fault' is an emotive word not applicable in this context. It is a gene which already pre-exists in people of a given racial type.
Since those with two copies of the gene for sickle cell suffer a genetic disease that is devastating, I also find it hard to view as a genetic balance, rather than a genetic defect.
The balance is that the sickle gene conveys benefits in one set of circumstances and harm in another. People who carry it are weighing the chances of anaemic complications against the imnproved toleration of living in a tropical climate
Examples of the latter being seen in action are what I have been asking about. Because natural selection is proven it has been witnessed in action. But examples of positive genetic mutations, the increase in genetic variation new traits, needed for natural selection to select from, seem thin on the ground. That is what I have been asking about.

I am not doubting natural selection it is the positive genetic mutations that are needed for natural selection to select from that I am asking about.

Are you saying different breeds of dog have evolved new genetic information due to mutation and become divergent species. I guess if the various breeds of dogs were only fossils they would probably be viewed as different species of animal.

But I thought the breeds of dog were just evidence of selection, that the animals genome was capable of significant variation, just like with people lots of different shapes and sizes, that selective breeding could result in distinctive features, like difference in human ethnic groups or isolated population or groups who do not marry outsiders.

With the exception of small dogs being a product of a identified single gene genetic mutation, like people who have a genetic trait leading to being midgets or dwarfs. But not what I would view as a beneficial mutation.

That is I thought a dog is a dog and we have not managed to selectively breed a change that produces new traits, like the sea creature evolving into the land creature, or the land creature evolving into a flying creature, that all we have ever got from selective breeding dogs is dogs. Because we have been missing the ingredient of the beneficial genetic mutations creating new traits form which to select.

The peppered moth is evidence supporting natural selection. It is not evidence of positive genetic mutation unless you are saying black is a new trait
Why do you keep banging on about 'positive' or 'beneficial' mutations?

I and others keep trying to tell you that there is no such thing. There are only mutations. A gene fails to replicate properly, creating a new gene, a mutation, which manifests (expresses) itself in the body pattern of its host. If that pattern allows its host to reproduce more successfully than those who carry the original configuration, then it will tend to increase in the population. If not, it won't. But it may only increase or decrease that tendency by a little bit. In that case, it will be absorbed into the genome of the species, and may eventually die out, or, if circumstances change, quickly become dominant.

In peppered moths, the black gene was always there, and black individuals were produced fairly frequently. In normal circumstances, though, they would be eaten by predators and therefore not reproduce. But enough survived to ensure the black gene was not eliminated. Black was not a new trait: it was primeval. It was just that circumstances did not allow black individuals to reproduce as much as the white until the dark satanic mills turned the tree trunks black. Then it was the whites which went onto the defensive.
 
This is a very good pub discussion.

@Dovercat There are other examples of what you are looking for, the majority however are difficult to identify, mainly as in order for a mutation to become established in a population can take a long time so as you can imagine a beneficial allele (a variant of a gene eg one with a mutation) in you right now may enhance your fertility, therefore instead of having 2 children you have 4. This is not something that would be immediately stand out as a "positive" mutation (as someone having four children is not that strange), however, if this took place 150,000 years ago the allele would most likely spread to a very high frequency and would therefore be much more obvious to scientists now a days, where as if it had occurred now it would take along time for this to be seen. So although these mutations that will have a positive effect are occurring it would be very difficult to see them now. Do you see what i'm trying to say? To overcome this difficulty it is best to focus on organisms with very rapid generations eg bacteria, in fact most cases of bacterial antibiotic resistance are the result of new "positive" mutations that then allow that bacterium to survive and replicate.

In terms of sickle cell you are right that it is due to a decreased susceptibility to malaria, although this is a "defect" in the terms OUR environment it is also positive in Africa in which Malaria is rife, so our classification of whether a mutation is positive or negative is based on context. Something that is of high benefit now and therefore would be judged by us to be positive may in a few thousand years be very damaging. For a example if you have a look at the thrifty genotype (Thrifty gene hypothesis - Wikipedia, the free encyclopedia) this is a theory that a number of alleles that allowed us to make the most of limited food availability thousands of years ago are now responsible for such dietary related conditions as diabetes.

@DPinBucks Yeah you're right, differences between species are much more drastic than within, but there is still an effect within species, i think it is perhaps important here to point out that other processes play very significant roles in reducing diversity such as at a population level eg bottle necks, for example the lack of genetic diversity seen in Asians and Europeans is believed to be due to the populations being established by a small group of humans that left Africa, therefore only their diversity is present in the people that are derived from them. I heard from an academic (I can't find it written so it may be wrong) that there is more genetic diversity in some East African villages than there is in the whole of Europe.
 
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@DPinBucks Yeah you're right, differences between species are much more drastic than within, but there is still an effect within species, i think it is perhaps important here to point out that other processes play very significant roles in reducing diversity such as at a population level eg bottle necks, for example the lack of genetic diversity seen in Asians and Europeans is believed to be due to the populations being established by a small group of humans that left Africa, therefore only their diversity is present in the people that are derived from them. I heard from an academic (I can't find it written so it may be wrong) that there is more genetic diversity in some East African villages than there is in the whole of Europe.
I don't think I mentioned the differences between species. All my discussion has been about intra-species diversity.

You are right about bottlenecks, and human ones in particular. The idea that we underwent a huge one about 70,000 years ago is still rather controversial. However, there have been studies which show that diversity diminishes the further the group is from Africa, and this is taken to indicate a series of bottlenecks during human expansion. It can account for the various human racial types around the world.

I wouldn't go so far as to say that some African villages show more diversity than the whole of Europe. I suspect the populations of such villages are not large enough to support such diversity, but I guess it's possible.

It would be interesting to see if studies show that human diversity overall has diminished over the past 100 years. I would think that in 100 years time it will be very much less than now.
 
No they aren't. What makes you say so?

I am not a scientist, I am a layman. So my understanding is no doubt flawed and very incomplete.

A disability is not a mutation nor a genetic defect. It is simply an unfortunate expression of already existing genes.

I thought not all genetic disabilities and diseases are caused by the parents passing on the gene. That some are random. So I assumed the product of random mutation or genetic damage. We also we have detonated nuclear bombs on civilian targets and have had nuclear power station accidents in populated areas, resulting in increased radiation. I am not a scientist so from a layman prospective that is some times said to have caused a increase in genetic damage and genetic mutation. We had still births, birth defects, genetic disabilities and genetic diseases and cancers. Outside science fiction and comic book fantasy, I do not think we got fertile mutants with beneficial new traits and new abilities that could create new species with radically new traits and abilities.

an unfortunate combination of the genes
It is a gene which already pre-exists

But is that not the same with the various breeds of dogs, expressions of combinations of already existing genes. Not new information, new traits, new abilities.

Why do you keep banging on about 'positive' or 'beneficial' mutations?

Because I am under the impression that evolution can not just rely on natural selection. That it needs added complexity, new traits and abilities being added from which it can select. That simple organisms evolve into complex organisms, with the complex organisms having traits and abilities not present in the progenitor simpler organism. That there has to be a means of adding that complexity, those beneficial traits and abilities, for those things to be available to be selected by natural selection.

I and others keep trying to tell you that there is no such thing. There are only mutations. A gene fails to replicate properly, creating a new gene, a mutation, which manifests (expresses) itself in the body pattern of its host. If that pattern allows its host to reproduce more successfully than those who carry the original configuration, then it will tend to increase in the population. If not, it won't. But it may only increase or decrease that tendency by a little bit. In that case, it will be absorbed into the genome of the species, and may eventually die out, or, if circumstances change, quickly become dominant.

It is examples of the new mutation, new strength, becoming dominate that have been seen as ongoing process, that I have been asking for. The evidence evolution the creation of new strengths, is in action now as a occurring process, rather than just evidence of natural selection from existing traits.

So far the examples seem to all be genetic defects. That coincidentally are beneficial in some circumstances. Like having one sickle cell gene causing defective blood cells along with good blood cells. Or examples of just selecting from existing traits like various breeds of dog, some of whom seem inferior or in some way could be viewed as deformed versions of the original species, etc...

The example by adbrand of Natural Selection Favors a Newly Derived timeless Allele in Drosophila melanogaster
was more convincing as a new strength arising and then undergoing natural selection. But it too could be seen as a genetic defect of a existing trait, that is coincidentally advantageous in some circumstance. As the creature is perceiving less light than their actually is giving it an advantage in higher altitudes as it goes into hibernation earlier.

In peppered moths, the black gene was always there, and black individuals were produced fairly frequently.

That is my point it is poof of natural selection. But I am under the impression that natural selection is only part of what is needed for evolution. If evolution is used to explain the evolution from simple organisms to more complex organisms and of widely divergent species with radical different traits and abilities like wings, feet and hands, gills and fins, etc... The creation of the added complexity, either via pre-existing in the genetic code present some how at the start like in the science fiction film or by being added to the genetic code by some process like genetic mutation, being needed to complete the explanation of evolution, natural selection alone just of already existing traits not being a full explanation.


Apparently in fossils there is evidence of increase in complexity of organisms and the addition of new traits and abilities, including radical new traits and abilities, What I have been asking is what evidence is there that it is occurring now as a ongoing process.

We know natural selection of existing traits is a currently occuring ongoing process, what about creation of new beneficial traits new strengths and new abilities from which natural selection can select.
 
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