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There are many great evolutionary geneticists who would challenge the idea that "natural selection" is the driving force of evolution. Kimura is the obvious example, but increasingly I find myself agreeing with the viewpoints of Masatoshi Nei who argues that it is really mutation. Depending on demographic factors, strength of selection, changing environment....there is a tradeoff on every trait between selection and genetic drift. One thing is for certain, both of these forces only act on the variation that exists and do not themselves produce any variation. In the short term, they may have more immediate impact on evolution, but over the long term, it is ultimately mutation that creates the variation. As a whole, I think the idea of trying to attribute one a dominant role to one of the four forces of evolution is silly to the extreme and ultimately has less to do with science and more to do with egos or attempts to undermine the science. Its a common tactic in creationist circles to try and use the neutral theory to undermine Darwin and on the other hand, there are too many Darwin fan-boys who have pushed the selectionist mindset to the extreme at the expense of admitting that other forces play an important role.

Edited by chadn737
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I'm always at a loss to understand why some people think we could ever do something that wasn't natural. We're part of nature

 

How many of your friends have died from a broken leg because they couldn't get food and run from predators? None? That's odd.

How many of your children have been eaten by wolfs? None? ! ? WOW! Same here! What a coincidence! That's very common for deer and other wild animals.

How are your teeth at opening nuts?

I wonder if people really understand how hard it is to live in the wild. And how easy we have it.

I say we may be evolving but not as fast as any animal in the wild due to natural selection.

 

I have said from the beginning that I think the driving force for evolution is survival of the fittest through natural selection. In the human race we (modern medicine) make sure everyone lives as long as possible (or at least well past child bearing years). I don't think survival of the fittest has much impact on us anymore. It's survival of everyone.

 

Several of you have said I have underestimated the other factors involved here such as gene drift and mutations. I hear you but I don't understand how gene drift and mutations can give evolution DIRECTION. In my previous example gene drift and mutations may cause people to have longer and shorter fingers but which would be more fit? More likely to be passed on in the gene pool? I can only see natural selection as the mechanism that gives evolution direction. Even when we talk about blood pressure, genetic defects, sickle cell anemia etc. etc. We still need the less fit to be less likely to survive. Maybe they are less likely but for an animal with medical issues it has a much bigger impact on them.

I think a dozen people have told me I have underestimated the impact of gene drift and mutations but no one has attempted to explain why gene drift and mutations could ever affect us more than wild animals that must struggle and fight every day to survive. They can't call 911. Can't get checkups and preventative medicine. Don't have billions of dollars spent to prevent cancer and other diseases? My big question is how could gene drift and mutations give evolution direction. I only see these factors providing variation. But variation is not evolution toward a new species. You only end up with some people with long fingers and some with short (or whatever trait).

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I'm always at a loss to understand why some people think we could ever do something that wasn't natural. We're part of nature.

How many of your friends have died from a broken leg because they couldn't get food and run from predators? None? That's odd.

How many of your children have been eaten by wolfs? None? ! ? WOW! Same here! What a coincidence! That's very common for deer and other wild animals.

How are your teeth at opening nuts?

I wonder if people really understand how hard it is to live in the wild. And how easy we have it....

 

I think Phi's point -and I agree with it- is that 'how easy we have it' as you put it is the result of human evolution. We did the evolving right along with the rest of nature. Our course is different but so is that of all flora & fauna. While our teeth may not gnaw through nuts, neither do those of most carnivores. Our teeth are however well suited to eating both seeds and meat. Neither are we unique in such social activities as caring for our offspring or our sick and injured or mourning our dead. Do you think a pack of wolves would not protect their young from a bear? Lick the wounds of injured members of their pack and bring them food? Not linger around the body of a pack member that died? And how easy will we and the rest have it were a massive meteor to strike? Do you think humans would not be able to use the same evolved adaptability to survive a return to the wilds?

Evolution only has direction in the sense that humans perceive time differently than other life forms and how we pass on information.

Edited by Acme
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Do you think a pack of wolves would not protect their young from a bear? Lick the wounds of injured members of their pack and bring them food? Not linger around the body of a pack member that died?

 

 

Each of those are very good points.

My point is that humans are far more likely to survive these hardships and therefore natural selection has less of an effect on us.

I will also repeat that evolution is still affecting us, just not to the degree as animals in the wild.

 

 

 

 

And how easy will we and the rest have it were a massive meteor to strike? Do you think humans would not be able to use the same evolved adaptability to survive a return to the wilds?

 

True. It would take a super creature to survive a meteor strike. It would probably wipe out civilization and we would have to survive in the wild.

That is unless there was a creature that could divert the meteor. Such as .... humans? Who needs survival of the fittest when you are as advanced as humans. We'll survive anything. .... well not anything but a heck of a lot more that the animals that live in the wild.

 

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Each of those are very good points.

My point is that humans are far more likely to survive these hardships and therefore natural selection has less of an effect on us.

I will also repeat that evolution is still affecting us, just not to the degree as animals in the wild.

But we aren't more likely to survive other dangers that 'wild' creatures don't suffer. Heart disease, diabetes, or such matters. Determining a 'degree' for the effects of evolution is a hindsight activity and one that is -so far as we can determine- a uniquely human endeavor.

 

True. It would take a super creature to survive a meteor strike. It would probably wipe out civilization and we would have to survive in the wild.

That is unless there was a creature that could divert the meteor. Such as .... humans? Who needs survival of the fittest when you are as advanced as humans. We'll survive anything. .... well not anything but a heck of a lot more that the animals that live in the wild.

But we evolved from creatures that survived a meteor strike in the wild. And the evidence indicates they weren't 'super' creatures but small mammals hiding in holes. While we may like to think we're better equipped to survive than 'animals that live in the wild', that is just an artifact of our evolved abilities of self-awareness and self-reflection. Duck & cover!! :lol: Edited by Acme
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But we aren't more likely to survive other dangers that 'wild' creatures don't suffer. Heart disease, diabetes, or such matters.

 

I disagree. Modern medicine and science has made great strides in these areas. Of course there are still problems that could kill us but we are far better off than we were before science and medicine.

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I disagree. Modern medicine and science has made great strides in these areas. Of course there are still problems that could kill us but we are far better off than we were before science and medicine.

I wouldn't argue that we haven't made progress, but again that is just a human concept and human concepts are just the results of evolution of our brains. Moreover it's not a concept shared by many folk who are always wishing and demanding we return to the 'good old days' as well as preaching about how science and medicine are the work of the devil. So again, we suffer dangers animals don't just as they suffer dangers that we don't. We & they continue to evolve but knowing what has gone to pass is no reliable predictor of what will come to pass. And even though you & I can relax in our homes and carry on such discussions as this, we will be long dead and [possibly] be the subject of later discussion of evolution in hindsight. Eat drink & be merry, for tomorrow we evolve. :) Edited by Acme
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How many of your friends have died from a broken leg because they couldn't get food and run from predators? None? That's odd.

How many of your children have been eaten by wolfs? None? ! ? WOW! Same here! What a coincidence! That's very common for deer and other wild animals.

How are your teeth at opening nuts?

 

What about people killed by cars, guns, electricity and other modern technology. Also, people still die of starvation, diseases and accidents. The selection pressures may have changed but they haven't gone away.

 

 

I say we may be evolving but not as fast as any animal in the wild due to natural selection.

 

You have produced no evidence to support this. Some evidence has been provided by others and it appears to contradict this belief.

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Evolution is change in allele frequency, so it seems logical that the factor that causes the change is the driving force i.e. mutation.

 

The problem is that our human brains do not understand the timescales of macroevolution. The timescale of evolution is dictated by long periods of punctuated equilibrium, which I'm sure to the observe seems to be static state. However biologists need to understand that the entire universe is under influence by the physical principle of entropy, and thus will always be progressive and never static.

 

Also evolution's major driving force was natural selection and the strive for fitness, however just because these concepts don't fit in our human concept of time doesn't mean it doesn't exist. Humans still select mates based on selective preference, which usually means a general strive for fitness.

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Also evolution's major driving force was natural selection and the strive for fitness, however just because these concepts don't fit in our human concept of time doesn't mean it doesn't exist. Humans still select mates based on selective preference, which usually means a general strive for fitness.

 

These are generalizations that have the potential to regress the ongoing discussion(s). As have been pointed out, natural selection is on important force in evolution, but depending on population structure and other factors, others may be dominant. Furthermore, you seem to be conflating various meanings of fitness. There is no striving for fitness, as obviously natural selection is the result of varying fitness associated with various genotypes (in the population genetic meaning, not in terms of physical fitness)

 

Especially the last sentence highlights the importance to be more precise when using these terms. Take elaborate and highly visible plumage in birds for example. In situations where predation is very strong, it may prove to be under negative selection (i.e. associated with low fitness). However sexual selection can offset this decrease in fitness,resulting in a net fitness increase.

Edited by CharonY
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There are two ways to stop evolving: Humanity's sole means of evolution is reduced to replacing every individual with an exact clone every generation, or we go extinct.

 

Anything else is inevitably going to result in a changing allele frequency in the population whether by selection or drift and evolution will thus occur.

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Furthermore, you seem to be conflating various meanings of fitness. There is no striving for fitness, as obviously natural selection is the result of varying fitness associated with various genotypes (in the population genetic meaning, not in terms of physical fitness)

I don't think anyone is misunderstanding fitness as it applies to evolution. We know we are talking about genetics not physical fitness that can improve with exercise.

 

 

There are two ways to stop evolving: Humanity's sole means of evolution is reduced to replacing every individual with an exact clone every generation, or we go extinct.

 

no one is saying humans have stopped evolving but I believe wild animals for which survival is a daily battle, are evolving at a faster rate than humans.

 

For evolution to take place there must first be variations in the gene pool. These variations may be due to gene drift or mutations. Due to mutations we may have people with longer fingers than other people. These variations are not yet evolution toward a new species.

Then there must be some guidance for evolution such as survival of the fittest. So you need both a variation of genes (maybe due to mutations) AND survival of the fittest to give direction to evolution. Maybe people with short fingers would be more likely to die and less likely to pass their genes off to the next generation. I think survival of the fittest is no longer directing our evolution. We are surely still getting mutations and gene drift but that is not offering evolution in any particular direction. Some people disagree with me but I still haven't heard any theories of what could be guiding our evolution if not survival of the fittest. I think everyone and their brother has told me we are still evolving. Okay, but my question is what is guiding that evolution? And to what direction (what traits)?

 

As stated many times I think we do have survival of the fittest but not to the degree of wild animals. Wild animals often have 12 offspring and only 2 end up living to bear young. This results in zero population growth. Insects may have hundreds of offspring with the vast majority dieing quickly.

 

Illnesses and genetic disorders may also cause us to evolve. But not to the degree as wild animals. To disagree with that statement is to say that modern medicine has not made any advancements at all since the beginning of civilization. Wild animals have disease but zero technologies to help them deal with these sicknesses. As a matter of fact I think the lack of survival of the fittest is causing what might be called negative evolution. By that I mean some disorders that would be fatal in the wild will still allow a human to live well past child bearing age. For example many humans have blindness, deafness, or there are countless genetic diseases and disorders that prevent people from running or even walking. If an animal were to be blind, deaf or unable to run due to muscular dystrophy or any other disorder or disease they would certainly die before having offspring. But deaf and blind humans live as long as the rest of us. For that reason I can see more people with genes for blindness, deafness and countless other genetic problems that we can deal with. We are also making great strides in almost all diseases. I even believe we will cure cancer long before we evolve into a new species.

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no one is saying humans have stopped evolving but I believe wild animals for which survival is a daily battle, are evolving at a faster rate than humans.

 

Your assumption is questionable for various reasons already discussed at length.

 

For evolution to take place there must first be variations in the gene pool. These variations may be due to gene drift or mutations. Due to mutations we may have people with longer fingers than other people. These variations are not yet evolution toward a new species.

 

This statement contains a number of errors: 1 Genetic drift does not result in alleles. I'd suggest re-acquainting yourself with what genetic drift is http://evolution.berkeley.edu/evosite/evo101/IIIDGeneticdrift.shtml 2: Evolution is a continuous process. Intraspecific and interspecific variation don't neatly seperate.

 

Then there must be some guidance for evolution such as survival of the fittest.

 

As has been repeated a number of times throughout this thread, there doesn't. Drift occurs in the absence of selection, or any other driving force. See previous link.

 

 

I think survival of the fittest is no longer directing our evolution. We are surely still getting mutations and gene drift but that is not offering evolution in any particular direction. Some people disagree with me but I still haven't heard any theories of what could be guiding our evolution if not survival of the fittest. I think everyone and their brother has told me we are still evolving. Okay, but my question is what is guiding that evolution? And to what direction (what traits)?

 

As previously posted, evidence such as that from the Framingham heart study directly contradict this statement.

 

 

As stated many times I think we do have survival of the fittest but not to the degree of wild animals. Wild animals often have 12 offspring and only 2 end up living to bear young. This results in zero population growth. Insects may have hundreds of offspring with the vast majority dieing quickly.

 

Fecundity =/= Selection.

 

Also, previous links have shown you that strong selection pressure often slows evolutionary rates by limiting genetic diversity. The (unsubstantiated) argument that humans are undergoing less selection pressure than an as yet unnamed "wild" species does not lead to the conclusion that the "wild" species is evolving faster. In fact the opposite is quite possible.

 

 

Illnesses and genetic disorders may also cause us to evolve. But not to the degree as wild animals. To disagree with that statement is to say that modern medicine has not made any advancements at all since the beginning of civilization.

 

That's a complete non-sequitur. See above.

 

As a matter of fact I think the lack of survival of the fittest is causing what might be called negative evolution.

 

There is no such thing as "negative" or de-evolution, as it implies purpose or direction in the evolutionary process. The idea has long been debunked. http://en.wikipedia.org/wiki/Devolution_%28biology%29

 

By that I mean some disorders that would be fatal in the wild will still allow a human to live well past child bearing age. For example many humans have blindness, deafness, or there are countless genetic diseases and disorders that prevent people from running or even walking. If an animal were to be blind, deaf or unable to run due to muscular dystrophy or any other disorder or disease they would certainly die before having offspring. But deaf and blind humans live as long as the rest of us. For that reason I can see more people with genes for blindness, deafness and countless other genetic problems that we can deal with.

 

The fundamental flaw in this argument is that the so called "deleterious" alleles are not out-competing so called "advantageous" or neutral alleles. A relaxation of selection pressure (if it even exists) allows for the accumulation of a higher diversity of alleles. As has also been pointed out, this is the fuel which fires the evolutionary process. A more genetically diverse population has greater evolutionary potential in a changing environment. The accumulation of a greater diversity of neutral, or mildly deleterious mutations in a population increases its potential to adapt. Hence rather the opposite of reducing its evolutionary rate.

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Thanks Arete. You have provided lots of information. Framingham heart study does show evolution is still taking place for humans. When I realize 80% of the deer and other wild animals do not make it to the age to bear young I see survival of the fittest being a strong force directing evolution toward traits that are better suited for survival. I still don't understand how we could be evolving as fast as the other animals that fight for survival each day but I will drop the topic.

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Arete trust me we know what fitness is, and none of what you have managed to say here has added to the quality of the discussion. Rather, it seems to me, and I'm sure others involved in this discussion, that your critiques are mainly for your own personal egocentric satisfaction.

 

We are not idots, you have successfully re-iterated most of what we have said with no additive value, except with a few feeble remarks on our thought process.

 

 

I would also like to add that ALL biological systems are pushing towards greater fitness, as long as we are procreating our species biologically. To assume that the human species has come to a halt evolutionary is a common human error, because our brains cannot process the timescales in which major evolutionary spurts take forth in. We must also respect the fact that most of macro-evolution is dominant by periods of punctuated equilibrium.

 

Also this is very ignorant and typical of a biologist to think that these laws are dictated by human "discretion" or organismal "discretion". These processes (as with all biological processes) are dictated by physical laws of nature and there is no law in physics that describes that a biologist or a biological organism has to be content with these principles.

Edited by AndresKiani
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Arete trust me we know what fitness is

 

Which I never defined in this thread.

 

that your critiques are mainly for your own personal egocentric satisfaction.

 

They aren't but I guess you're entitled to your opinion.

 

We are not idots

 

My irony meter just broke.

 

except with a few feeble remarks on our thought process.

 

Which I never commented on.

 

I would also like to add that ALL biological systems are pushing towards greater fitness

 

Demonstrably false. Drift can cause the fixation of deleterious alleles in a population leading to reduced fitness -

 

http://www.nature.com/hdy/journal/v110/n3/abs/hdy201286a.html

http://www.genetics.org/content/198/4/1587.short

http://onlinelibrary.wiley.com/doi/10.1111/j.1558-5646.2011.01311.x/abstract;jsessionid=4858B37A1780144F265243325AF57DC3.f03t04?deniedAccessCustomisedMessage=&userIsAuthenticated=false

 

Also this is very ignorant and typical of a biologist to think that these laws are dictated by human "discretion" or organismal "discretion".

 

Which is a strawman as I never said anything of the sort. Nor have I ever heard any biologist of note claim that evolution is dictated by anyone or anything's "discretion". This seems to be something you made up.

 

 

and there is no law in physics that describes that a biologist or a biological organism has to be content with these principles.

 

This doesn't actually make sense to me - care to elaborate?

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my question is this.

if we have saturated all ecosystems, then do we lose the benefit such things brought us in the past.

we are clearly still evolving as our teeth, skull, and other things have changed. however, this may not be relational to what the topic refers to as it is a large timescale involved.

another question i have is whether or not such evolution will be sucessful in the future.

we may very well topple from evolution's finest creation.

aren't we over specialized already?

any more could wipe us clean off the earth if the environment evolves new niches.

what if we run out of oil?

our advantage through selection has undoubtedly made us smarter unfortunately it is easily put to rest without resources.

if we extend to a new niche like space, then it will force evolution yet again just as a new niche does.

sorry guys, this is the extent of my knowledge of evolution.

arete?

am i understanding this correctly?

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Again you're adding no value to this discussion you're simply scrutinizing other's comments.

 

I applaud you though for your persistent

 

 

 

 

Which I never defined in this thread.

 

 

"Furthermore, you seem to be conflating various meanings of fitness. There is no striving for fitness, as obviously natural selection is the result of varying fitness associated with various genotypes (in the population genetic meaning, not in terms of physical fitness)"

Nice contradiction. :)

 

 

 

 

Fitness has a general interpretation, thus your antics to scrutinize other's comments is ill placed, simply due to the fact that neither of us have used the term out of context. Based upon my knowledge fitness is defined best by survivability of an organism. Neither one of us has used this term out of context, therefore your huffing and puffing is not needed in our discussion. Ofcourse if you feel the need to protect your ego, by all means go right ahead.


 

Yes we are well aware that drift can cause fluctuations in allele frequency as well as desertion of certain alleles. Yes, thank you for the Bio 101, and again as with most of your comments, no value in this conversation what so ever.

 

Though this does not describe general directionality of organic evolution in at it's broadness, as if this happened to be the case biology would have never sprouted. Genetic drift is generally a poor argument to the fact that better fitness is the general driving force of biological systems. This being said evolution will not cease, again this goes back to my previous comment.. These laws that dictate biological systems are in turn dictated by physical laws, and so it is the failure of the biologist such as yourself to think otherwise.

 

I would also like to add that throughout the history of biology, genetic drift both random and non random, recurring mutations, migration, natural selection, and other factors have all led to the general trend of organic evolution.

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. I even believe we will cure cancer long before we evolve into a new species.

And there lies the root of the vast misunderstanding and technical ignorance you have been displaying throughout the thread: you think evolution is about the evolution of new species.

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I don't think anyone defined evolution for the purpose of this thread which might put you guys on the same track...

After all, if all we can do is argue, lets at least argue about the same thing.

Perhaps such technical ignorance is a reflection of a master's pride.

We learn from those we see.

I have lemonade because i know how to make it.

You have a lemon no doubt...

Does this make me more evolved or just superior? :blink:

Edited by davidivad
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AndresKiani, you have quoted me and not Arete with regards to fitness. And even then I have not provided a proper definition of fitness, just pointed out that your assumption for something like striving for general increase in fitness does not hold. But it does not appear that you understood where the issue lies. The reason why I and others commented on your sweeping posts is because they reflect general misunderstanding of evolutionary processes.

 

Yes we are well aware that drift can cause fluctuations in allele frequency as well as desertion of certain alleles. Yes, thank you for the Bio 101, and again as with most of your comments, no value in this conversation what so ever.

You entirely missed the point. If genetic drift results in fixation, how can, for that population, natural selection be the main driver? If you want an example of something that is free of content and not contributing to the discussion try this for size:

 

These laws that dictate biological systems are in turn dictated by physical laws, and so it is the failure of the biologist such as yourself to think otherwise.

 

As it is silly on so many levels. Obviously everything is based on physical laws, except that there is nothing that determines natural selection as the sole or even primary force in all populations as a general rule.

 

Also, are you actually aware what fitness means in a genetic context? Because

 

Based upon my knowledge fitness is defined best by survivability of an organism.

That does not quite cut it. Fitness can be defined in various ways but is generally a measure of the contribution to the next generation of a given gene pool. If an organism just survives it does not mean that there is any contribution. Rather, your definition fits the concept of physical fitness much better (especially your earlier quip with regards to sexual selection could be interpreted that way), hence my earlier comment.

 

 

Genetic drift is generally a poor argument to the fact that better fitness is the general driving force of biological systems.

 

This is what we call a circular argument. You have clearly demonstrated that you do not, in fact have a good grasp on the concepts and when an expert such as Arete point things out it is a good time to read up on them, rather trying to handwave arguments away by stringing key words together.

 

I ask again, do you understand the contribution of non-selective events to evolution? Also somewhat related you should check out the concept of stabilizing selection. In that context, it would be beneficial to read up on the concept of fitness landscapes (originally introduced in the 30s or so). Here, we model the effects of mutations on fitness in a three dimensional graph. If we imagine hills as local maxima of fitness. Depending on how ragged the landscape is, populations can get stuck at these local maxima that may not present the global adaptive peak. Now, fitness is not static either, thus the landscape can change and so what is seen as an increase from any point of the landscape.

Thus, the image selection (which, again is in many populations not the main force), towards the maximum is rather incomplete (and does not fit existing data well).

 

I am pretty sure that Arete can provide a more detailed and applied description, though I am not sure whether it is worth the time (leading camel to the water and all that).

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Andres, neither CharonY or Arete need me to defend them personally, and their technical positions are unassailable. I'll just say two things:

1. One of the neg reps came from me and I was disappointed I felt the need to award it, for I love your enthusiasm.

2. Stop being such a dick.

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