Evolutionarily Stunted?

To the extent that humanity has interfered with the natural process, it has invalidated evolutionary theory as it applies to human beings.

If evolutionary theory implies that the "fittest" survive, I am sure that Nietzsche would argue that the advances in medicine and public hygiene, for example, have resulted in the opposite: the botched and bungled survive to the detriment of the species.

Thanks, I se you started another thread on this. We can engage Creationism there.

We don't need to evolve anymore though I wouldn't mind a bigger brain . Why I'm saying we don't need to evolve anymore is because whatever benefit evolution could bring upon homo sapiens sapiens it will have already been brought by science millions of years in advance.

I will reply with a better post later, but first of all, that statement was so shallow if I adhered to that I'd be immuned to drowning.

:lol:Ok that was shallow:brickwall:

Sorry:o, Bronchitis has made my brain go all fuzzy.

I have to disagree. We do not fully understand why there is evolution in the instants there is evidence for. And we need to know why in order to know how natural you'd call it. I mean, if I defined evolution as natural, I'd say it is so long as our evolving isn't defined by our consciousness, consciously.
The cancer is the technology we use to evolve in an indifferent matter. Healthcare is usually fine, it is needed to keep people alive. Ironically, we are trying to stop cancer with it.

Hey ya Vid, thanks for responding,



You think so? Maybe I've got it wrong, but the basic functionality of Natural Selection - as I understand it - proports that certain physical attributes [1] either help or hinder the chances that creature will live to pass on their genes. Take me, for example.

• I wear glasses (and my vision is extremely poor) and have done so for the last 35 years. In a pre-modification scenario (let's say, 1,000BC) I don't last very long; at age 10 I walk headlong off a cliff. I didn't live to pass on this attribute to any offspring.
  
• In a post-modification scenario (say, 2008!) I live a good long time and pass on poor eyesight to two healthy young men who also have it, and pass it along to their children.
  

This is my basis for asserting premise 1. We've modified ourselves to survive when natural selection (as the theory sits) says we shouldn't perhaps even be alive. By this modification, isn't this 'thwarting' the process? If not, I'd like to hear how you'd say it 'augments' <?>



Hmm.. nothing natural about evolution? If you subscribe to the evolutionary/natural selection process I'd think one would think it the epitomy of "natural-ness". If you don't subscribe to the theory, then we're probably talking apples and oranges, in terms of what the thread is addressing.



Fair enough.

I'm curious though, do you subscribe to evolution as a viable, likely explanation to how life has come to be on this planet?



Good stuff here, thanks. The first portion (quote above) goes to the heart of this thread's question. And I concur fully that evolution's effects aren't always rosey... nature misfires more times than it 'hits'. If the theory holds true, then the only 'celebration' - so to speak - is in the understanding.



Good point; it could very well be!



Actually, no. A mutation can cause cancer, but all mutations don't necessarily lead to cancer. Mutations occur all the time in all forms of life for various reasons.

Thanks for your response. I've enjoyed hearing your perspective; I never cease to be amazed at how much 'new info' can be gleaned just by talking these issues. :a-ok:

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[1] Changes that have arisen through either adaptation to the current environment, changes in the environment itself, genetic 'drift' or genetic mutation.

Holiday,Khethil,

I think you pick up on some very good points!

As to premise one, it sounds like you assume that natural selection is always a positive thing though that may not be the case. My assertion is it may not always be the case. Also, your example underlines the evolutionary benefits at 1000 BCE. But times are different now. Your indeed correct, you would not have the same advantages as you do now, in 2008. But you do. You have glasses. Your body does not need to naturally compensate for something (theoretically) that is corrected by technology. Perhaps you base your assertions off of the fact that we should still be in 1000 BCEper senot cause cancer, I said that evolution is a mutation in our genes. That mutation (platelet derived cell growth) is a cause of cancer. That all mutation don't necessarily lead to cancer is agreeable. But I do not imply an extreme argument like that, only a parallel in the concept.

... hmmmmmmmmm - seems to me that human culture is evolving at an insanely rapid rate (relative to the rate at which speciation occurs) ... and that's just the tip of the multi-level-evolution iceberg ... there's good ol' natural selection ... with the appearance of intelligence, there's now artificial selection ... there's inter-species co-evolution/selection ... in higher primates there's cultural evolution ... there's the evolution of an individual mammal's immune system that occurs within the lifetime of an individual, elements of which are passed on to the next generation through mother's milk (Lamarckian evolution is not dead!)

Lot's of tangents to go off on, but I believe the thrust of your questions are oriented toward the Darwinian speciation flavor of evolution (and the natural selection variant at that) ... some recent speculation in that area would tend to confirm your hypothesis ... for speciation to occur, small isolated populations are required over large timescales in order to give individual mutations a reasonable chance of taking hold ... however, this is distinctly not the contemporary human situation ... so there seems to be little room for human evolution in any direction purely due to the globalization of the human race.

As for reliance on advances in prosthesis technology (power tools, contact lenses, cell phones, computers, etc.) - the "gadgets" you mentioned ... sure, if a meteor strikes tomorrow there are going to be lots of folks dying of starvation because the only way they know how to obtain food is from a grocery store ... but does that mean we should all return to a hunter-gatherer lifestyle because it's a more adaptive strategy in the event of such a cataclysm?

Speaking of cataclysms - let's try a thought experiment ... generation after generation, human technology allows individuals to survive and reproduce who wouldn't have been able to in eons past ... stated another way, mutations that might have not been viable in the past are now filling up the gene pool to overflowing ... so then a meteor hits and drastically changes the environment ... is having an overflowing gene pool a good thing? - that is, if humankind is faced with an evolve-or-go-extinct situation due to such a cataclysm, does having a giganto number of directions in which to evolve increase the odds of the successful evolution of humankind?

Good post Paul,

Yea, I think you caught the thrust I'd intended. But you're right, there are many types/flavors of evolution - each one with its own cautions.

Random thoughts on Replies Here:

• I believe that Natural Selection is the primary avenue by which life has evolved on our planet. I don't have a Darwin t-shirt, nor am I president of the Natural Selection Fan Club. There's much evidence and there are many holes. Like all beliefs, I'll subscribe to the one that holds the most credibility with me until such time as its supplanted by something more credible.
  

• Natural Selection, if this is indeed the way this all happened, I see like a thunder storm. Its neither good nor bad in and of itself. Some will wonder at it, while others curse yet there it sits - doing its thing. The only admiration, per say, that I might hold for this (and other natural processes) is insight into understanding life itself. I'm sure this will be an ongoing process for all of us - for a great many years to come.
  

• The word 'Stunted' may have negative connotations, but if we *have* had an effect on natural selection in this manner, I don't really see that as a "bad" thing, only one with implications derived from the benefits we do currently enjoy (which, I'm suggesting here took a distinctly different path).
  

Thanks again for your insights, I hope this exchange has been as informative to others as it has been for me.


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Hiya Khethil!

First, I want to make sure you are aware of genetic drift. A bit on what scientists think about the importance of drift:

Random Genetic Drift

Genetic drift - Wikipedia, the free encyclopedia

A bit on what genetic drift is:
Genetic drift - Wikipedia, the free encyclopedia

I think of genetic drift as a near mathematical inevitability in genetics.
A decent analogy/ little experiment you can perform to demonstrate this is here - Basic concept of drift - wikipedia.
Another point:


So part of what we are and what characteristics we have is probably due to genetic drift, as well as natural selection. Also, even if we seem to thwart adaptive evolution in the short term, since we are made of cells governed by genes we can be pretty sure that we haven't completely thwarted all evolutionary processes. The reason I say "seem" is because even though many modern humans don't deal with the same selection pressures our ancestors did millions of years ago, there might be different selection pressures of some relevance that we now face, as well as the fact that some humans, in parts of Africa for example, do actually still deal with many of the selection pressures that were adaptively imporant in our evolutionary past. The reason I say "short term" is b/c things can change quickly. Think about the impact that earthquakes, hurricanes, volcanic eruptions, asteroid impacts, and nuclear war could potentially have on our species. We are but a blink of an eye in the face of life on this planet. No matter how easy things seems for us now, things could change quickly. Just look at the dinsosaurs, they dominated the Earth for FAR longer than humans have so far, and in general were amazingly well adapted for life on this planet, yet when faced with a couple of natural catastrophes such as major volcanic activity and an asteroid impact, they were largely eliminated from the face of the Earth.

So now that I've said all that, I'll return directly to the points in your OP.

In Premise 1, I personally think it would be more accurate to say that we seem to have stunted adaptive evolution in the short term; this is somewhat semantic, and I do get your point, but it's important to note that we have NOT stopped evolution in humans. Most evolutionary change that is even slightly significant usually takes place over extremely long periods of time, especially in species with life spans as long as ours. Just b/c we have come up with extensive medical care over the last couple 100 years doesn't, at this point anyway, necessarily mean that much in terms of processes that typically take hundreds of thousands, and millions of years to to do their work in a significant way.

I have little quarrel with Premise 2.


Here I would change "any evolutionary processes" to "any adaptive evolutionary change" and also go back to the point about how long major evolutionary change usually takes to happen. (since you mentiond periods of time within the past few hundred years) I assume that if things keep going the way they currently are for a long time, we will become increasingly reliant on our gadgets and systems; our way of life and environment. This is the way it is for most species. If they live in one environment with certain circumstances for a long time, then they become reliant on those circumstances, and find themselves unable to survive in the face of abrupt changes, should they occur. So when you ask if we are to become less able to withstand, if you mean less able to withstand in the face of environmental/ circumstantial change, then yes, the more control we become accustomed to in our environment, the less we will be able to withstand a sudden lack of control in this regard. We haven't "short circuited" the system IMO, b/c the system is still all there; we are still made up of cells governed by genes, and evolutionary processes still govern life. If our environment is to drastically change in the future, well, we'll just have to see how far our bodies and ingenuity take us. Just like 99% of the species that have ever lived on this planet, our future will likely be extinction. If anything, we might be MORE able to withstand change however, due to genetic engineering.

Are we missing out on any evolutionary change that we might have experienced should we have not developed medical care? Well, first consider that we may have all died by now if it wasn't for medical care, which would make the question moot. Next, consider that this is how evolution works. Major evolutionary change tends to cease as long as a species is well adapted to it's enviroment, and the enviroment doesn't change much. Look at many deep sea animals; their world has seen little change over hundreds of millions of years, and those that have been well adapted to their enviroment haven't changed in any significant ways for many millions of years. Things are essentially no different for humans.

So I would say that no, we have not "sapped our future".

Would it matter if we had though? Well, if you value the preservation of our species, and if we've made ourselves less robust and/or able to survive in the future, then yes, it would matter. But let's consider the alternative to doing what we can to help members of our species survive and overcome past selection pressures; to let the "weak" suffer and die. We would have less reproducing individuals and if we weren't lucky, the process could runaway and be more likely to completely kill us out. So I'd say it matters if it makes us less able to survive, but overall, I'd say that it probably doesn't. It does perhaps make the average individual less robust and physically capable, but it also helps to keep us alive as individuals and as a species, as well as to reduce suffering.

Khetil,

Evolution requires three things:

1. Variation of phenotypes within a population.
2. The passing of genetic traits from generation to generation.
3. Time.

As far as I can tell, the human race has not managed to eliminate any of these factors.

Evolution lives.

I can make two observations on this matter:

1. Evolution has not been halted. What has happened is that our changed living environment has changed the fitness landscape which determines the traits that are most likely to be selected. It is just to be hoped that a genetic predisposition towards eating hamburgers is not one of those traits.

2. While evolution is still merrily doing its thing, it slow-moving processes are being rapidly overtaken by changes in technology which evolves at a rate which is about 100.000 times greater.
So evolution is still working, but it may be rendered irrelevant. You can still sail across the Atlantic ocean, but taking the plane may be a better idea.

I agree with the above. We only have so much control. Evolution is a function of 1) generation of new DNA sequences through mutation / recombination / etc, 2) nonselected changes in gene frequency, 3) effects of finite population size and population movement, and 4) natural selection that exerts positive or negative reproductive pressure on certain genotypes in the context of certain conditions in the world.

Modern science and medicine can theoretically mitigate all of these, but it's spitting in the ocean on a grand scale population level, and there are very few variables that we truly control in the end. And who cares if we've evolved differently by virtue of our inventions, part of species adaptation is behavioral, NOT genetic, and medicine (like any other tool use) is part of our behavioral and cultural adaptation to the world we face.

Just waiting for another trigger.

Good replies folks,

Yea, I'm well aware that there are quite a few other factors in our entire evolutionary process than just natural selection. This is simply the most pertinent with regards to our potential effects.

And yes, I think I'd agree on the whole. I especially like the answer that calls to mind the sheer quantity of time much of our genome changes require. The past few hundred years of using our "crutches and toys" isn't likely to make much of a dent.

Thanks again - good stuff

Khethil, I see where you're going with this but would like to throw in this consideration:

Darwin's theory of natural selection did presume fitness for survival as a criteria for reproductive success, however a moment's thought shows this to be a contingent factor. The most fundamental consideration always was and always will be the maximising of offspring: the family tree with the most branches wins. Until recently, fitness for survival was a necessary factor for maximising offspring. What we see now, in the human species at least, is that fitness for survival is largely irrelevent of biological characteristics for reasons you have already pointed out.

But the organism with the most offspring still wins. There is a biological aspect to this: genomes that predispose one against procreation will tend to produce less offspring. Either the individual does not reproduce, or generally it reproduces only once or twice. Beyond this the conditions for reproduction are largely social and irrelevent to biological characeristics effecting survival (or more that survival is biology-independent beyond those characteristics that reduce procreation).

This is not to say evolution stops. We are, for instance, getting taller as a species but now the true factors effecting evolution are refined: sexual selection must always rule. That one's sexual partner has a pulse, in a way, can be considered a characteristic conducive to mating. But there are others. One could examine which characteristics are most sexually attractive (and we do - for instance, facial symmetry) and see over the generations whether the species is converging on these characteristics.

And of course there is the more arbitrary social element. Certain individuals prosper in certain social environments. Here in the UK we have child benefits for the unemployed. This offers a huge incentive to those who cannot or will not work to keep reproducing - you can actually make a good living from producing more babies in the UK, and indeed people do. This, more than medicine and technology, really screws with natural selection since those who procreate the most will differ under different governments in different countries.

Evolution that is fitness-independent will necessarily be slow (edit: see above post on genetic drift - sorry, didn't see page 2), but as long as there exist fixed characteristics for success at reproduction it should continue. However this contends with the more erratic dependence of reproductive success on arbitrary social factors.

Another issue is the success of other species which now depends less on the fitness for survival relative to a given species' natural environment and more on policy decisions of our species. The species that are most adaptable to our own environment will abide; those that aren't will become extinct. This is evolution, but there's nothing natural about it.

These are some thoughts I've had about this issue.

Anyone agree that the primary thrust of natural selection's influence on humans is in the process of moving from the physical to the mental? I say this because it seems we as a race are progressively getting a stronger and stronger at manipulating our physical worlds to such a degree that we can either "inhibit" or "speed up" the evolutionary process as it has been historically understood (I guess it just depends on how you look at it--personally I think our technology has simply caused evolution to speed up exponentially). --ie, we use glasses when a genetic mutation would have had to develop to fix faulty vision, or clothes instead of hair, etc.

So we can alter evolution to the extent that our technology allows. Physically speaking, we are replacing natural selection and random genetic drift with technological evolution.

Since we're assuming the validity of contemporary evolutionary theory, let's go back to the days of the ape-men. Let's presume there was a "eureka!" moment in which they first achieved self-consciousness. Ever since that moment, we have re-defined a new evolutionary path--the natural selection of mental states. Ever since the 'idea' came into being, there was added a new dimension to the self-preservation impulse that drives organisms. Not only would the ape now have to preserve his anatomical self, but also the expression of himself. The impulse in the organism holding this 'idea,' this 'expression,' to preserve itself extends to the expression as well.

As a child of the postmodern information age, I am exposed to more information everyday than anyone in the 18th or 19th century could have hoped for in a year, maybe a lifetime. As a result -- I can't imagine how much my own mental states differ from someone of the past, much less someone in the days BC. Therefore, the evolution of mentality makes great sense to me. Expression is prone to the same evolutionary scrutiny as anatomy--and we are building towards a greater understanding of this in itself (computers).

Insofar as we have been able to 'stave off' natural selection's dominance over our physical development, so do I believe we will do for mental evolution. Modern computers are a tiny peek into that window--and who knows what the next century will bring.

biased gene conversion and evolution...taking some of the certainty away from the the Neo Darwinian Natural Selection Fundies

Natural selection is not the only process that drives evolution


ScienceDirect - Trends in Genetics : Adaptation or biased gene conversion? Extending the null hypothesis of molecular evolution

---------- Post added at 07:38 PM ---------- Previous post was at 06:13 PM ----------

Hi Paul. does not Neo Darwinian Natural Selection apply to the phenotype rather than the genotype?

anyway, here's a couple of interesting articles
http://www.isnature.org/Files/West-Eberhard_Adaptive_Innovation.pdf


The oldest domesticated fishes, and the consequences of an epigenetic dichotomy in fish culture. - Free Online Library

I think an important point that is being overlooked here is that material culture is natural, and really should be taken as part of the environmental niche in which we fit.

No one thinks twice at seeing otters break clams on rocks or chimpanzees using sticks to fish for termites. This sort of tool use is behavior that benefits the animal, and even though the actual use of the tools seems to be intergenrationally transmitted through teaching, the inate ability to comprehend the usefulness of the tool is probably selected for.

Our technology is our envirnoment, and just as stated in an earlier post that if technology failed on a massive scale people would die because they didn't know basic survuval skills, how is that different from any other ecological niche crashing and a species or a majority of a species die off? When thinking of humanity it is wrong to use a traditional defenition of nature and natural. Our material culture is our nature and it is natural for us to use it. It has become an extention of nature, as it is traditionally defined.