Is evolution going backwards?

In the past, Before civilization started to form, there was many species which were extincted due to prinicipal 'survival of the fittest'.according to this: http://www.ncbi.nlm.nih.gov/entrez/...
{Shortened display form of URL, to restore page width to normal. - Adminnemooseus}it is estimated that in the human genome in each birth there is 175 netural mutations.
and 3 mutations are deleterious, and fewer are beneficial.
since, that the 'survival of the fittest' is no longer taking an effect. and since most of the mutations are deleterious,
putting the two togethar in a 100,000 years from now the number of the 'negative' mutations will be simply enormous..
and diseases rate will be higher, medical proffesionals will need to deal with much more medical conditions..there for, the question is what does the future holds for homo-sapiens?This message has been edited by Adminnemooseus, 01-05-2005 21:00 AM

Thread moved here from the Proposed New Topics forum.

How do you figure? Most of the world doesn't get enough to eat, or have adequate housing. For instance, the life expectancy of a person living in most of Africa is under 55 years. Sounds like negative selection is very much in play for the human population.And that doesn't even get into sexual selection, which you can't get rid of. You know, unless all human beings learn to reproduce asexually.Natural selection is very much still at work on the human species. Even in this country.

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How do you figure? Most of the world doesn't get enough to eat, or have adequate housing. For instance, the life expectancy of a person living in most of Africa is under 55 years. Sounds like negative selection is very much in play for the human population.

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But theres no selection going on, unless the selection is for being rich, or in large part, European. The fit and the unfit, in all meaningful senses, are dying in the third world right next to each other. This is also in no way natural given the massive wealth being extorted out of Africa by the West and the debt industry. This is not any form of natural selection but instead human selection, in that this is really a form of economic warfare. Modern poverty is not a natural problem but an artificial one, and thus does not constitute natural selection.

Evolution does not move forward or backward. It can only continue. Random mutations happen and if these random mutations lead to that organism no longer being valid ( no longer able to exploit or survive in it’s environment), well though luck for that organism. But the amount of change per generation is, as pointed out by someone else so slight as to be insignificant compared to the socio-environmental effectors on our health wealth and happiness.As to ‘fit’ and ‘unfit’, in regard to natural selection, I would like Contracycle to define what he means by these terms, as natural selection is always happening. After all we are more ‘advanced’ than monkeys for example, but dose that mean that there should be no monkeys left? After all we are ‘fitter’? No they are an equally valid solution to surviving their environment as we are to ours. However If we have to compete for the same space, things are likely to go badly for the monkeysAs for Humans then there are people more suited to surviving the human jungle than others. This isn’t down to who has money and who doesn’t, but more to do with how the individual deals with the dangers and opportunities that the human jungle offers. After all even the richest man can die lonely and broken with no family where as the poorest man can live a long and happy life with a loving supportive family. People kill themselves because they can not cope with the stress of modern human life. These people are not able to successfully exploit their environment to survive and are thus not ‘fit’. Believe me natural selection is alive and well in today’s world.And as modern medicine improves the boundary of a valid ‘fit’ human increases. Not to many years a go Prof Stephen Hawkins would have died early or been locked away in an asylum. No one would have considered him ‘fit’ but today due to medicine and changed attitudes to certain disabilities he is in ‘comparatively good health and one of the most acclaimed minds of our species. There are many people who can thank their survival to modern technology, where as previously these people could have been classified as ‘unfit’.As I said natural selection is still alive and well. You just have to know where to look.

Welcome to the fray.First off I have some problems with your numbers.You say And then Now the last time I looked 175 neutral mutations was greater than 3 mutations by a factor of, oh, somewhere around 58.3.But the article also gives some different background to those numbers: That’s a total of 175 mutations within the whole diploid genome per generation and the total sites would be 175/2.5x10^-8 or 7x10⁹. That means a lot of sites that are not affected (understatement), without even going into which sites have more mutations than other sites (it is not an even average process - some sites are much more "active" in mutating than others, which also means that already existing mutations there are more likely to be further mutated and alter the effect of the original mutation).

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Next, aside from the issue of whether 1 site in 7,000,000,000 per generation is high or low as a rate of mutation, if the individual survives to reproduce they are de facto neutral mutations for {him\her} - they have not prevented {him\her} from reaching reproduction age or from reproducing.The article also states: From an evolutionary point of view it makes sense to have mutational experimentation to be more prevalent in the more disposable sex (loss of a few males will not reduce overall reproduction as much as loss of a few females would). On a serious note that would mean that deleterious effects should show up in the male population to a much higher degree than in the female population, but: (Note the definition of epistasis that applies here: An interaction between nonallelic genes, especially an interaction in which one gene suppresses the expression of another.)Thus it would appear that some deleterious mutations are neutered by suppression of their expression by other (watchdog type?) genes. The mutation is {turned off\disabled} as far as {cell behavior\reproduction} is concerned. I suspect there are an awful lot of those in what are called the junk gene sequences.And we don’t know from the article what their use of the term deleterious means — is it lethal? Is it sickly? Or is it just a socially unacceptable feature, like oh, yellow hair? We will assume that deleterious means that it negatively affects the net reproduction of the individual with the gene, as anything else is irrelevant as far as evolution is concerned (evolution doesn’t care if you are genetically more prone to getting Alzheimer’s at 84 years of age, for example).

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The next question is whether those "deleterious" mutations accumulate in the genome or if there is a mechanism that "flushes" them out.Every mutation, whether beneficial, neutral or harmful must survive and reproduce, and in the case of genes (as opposed to individuals) the reproduction includes a chance issue: the mutations are only on one side of the DNA so half of the {sperm\egg} will have the mutation and half will not.Lets take an example, a specific gene site A is mutated into B -- If possession of one diploid B is lethal the individual dies without reproducing, otherwise it is neutral for the survival of the individual in the single diploid concentration.If possession of a double B is lethal then we have a different situation. For it to be passed on the individual must be able to reproduce and pass the mutation to the next generation — it has to be neutral to the survival of the gene as well as the individual. Now we have a population generation that has a lot of {A-A} types and some {A-B} types and as long as there is no deleterious effect on the individual surviving and reproducing and passing on the {B} genes then the mutation is neutral. In the next generation we can have some {B-B} types that then die before reproducing to pass on the gene: the deleterious effect is realized in those individuals. Will the {B} mutation spread in the general population?All things being equal (they aren’t) then:all {A-a} to {A-a} matings will produce viable offspring in all the four possible combinations (AA, Aa, aA and aa)all {A-a} to {A-B} matings will produce viable offspring in all the four possible combinations (AA, AB, aA and aB), half of which carry the mutation forward another generationall {A-B} to {A-B} matings will produce viable offspring in 3 of the four possible combinations (AA, AB, BA and BB), two of which carry the mutation forward another generation.The next generation would then be likely to have where
N_AaAa is the number of {A-a} to {A-a} matings
N_AaAB is the number of {A-a} to {A-B} matings
N_ABAB is the number of {A-B} to {A-B} matingsNow from this you can run a number of scenarios with variations on numbers of matings, and you will find that there will always be {A-a} individuals and there will always be {A-B} individuals, and that usually the {A-a} individuals will far outnumber the {A-B} individuals. (Even if N_AaAa = N_AaAB = N_ABAB then {A-a} results have a 7 to 4 advantage over {A-B} results)This holds if the mutation is not lethal to the individual but prevents reproduction instead (such as having two copies makes the individual sterile).

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The persistence of a mutation in an individual or a {set of individuals} does not mean that it is pervasive in the whole population: not everyone has it.If there is something that increases the ratio of {A-B} to {A-a} individuals then the situation changes. This is what happens with sickle-cell anemia: people with the {A-B} combination are resistant to malaria, while those with {A-a} die of malaria and those with {B-B} die from sickle-cell. Take away the malaria (move out of disease prone areas or provide medical treatment) and the population proportion of {A-a} people will increase. This is observed. The proportion of people with {A-B} will not zero out, but will decrease to an equilibrium level. If sickle-cell is medically cured then the numbers of {A-B} and {B-B} people will increase, but the mutation will also have been neutered.Note: beneficial mutations are subject to the same numbers problem, and thus will not become prevalent in the total population unless they provide a clear survival\reproductive benefit that gives the modified gene a {multiple} advantage over the old gene.Thus my conclusion is that any mutation that prevents the survival or the reproduction of the individual is harmful and is removed from the gene pool by natural selection, and any mutation that does not do this is neutral, neutered or beneficial. That to me says that natural selection is alive and well and working in today’s world for humans just as much as it is for any and every other species.Enjoy.This message has been edited by RAZD, 01-06-2005 10:29 AM

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

Do you honestly think there's no selection going on in cases where large numbers of people are dying, in situations where environmental selection pressures are strongest? That there isn't selection for disease resistance, thriftiness with food metabolism? There may not be an anti-genocide mutation coming around the corner anytime soon, but it seems preposterous to think that world-wide deaths are completely independent of fitness in "all meaningful senses".

"Survival of the fittest" just refers to whichever genes are currently successful at getting passed on. Unless you think that currentlya) everyone has a perfectly equal chance of reproducing, or thatb) the chance of reproducing is 100% completely independent of genetic concerns,Then there's no reason to assume that there is no "survival of the fittest".Which one (a or b) are you arguing for?This message has been edited by Zhimbo, 01-06-2005 11:46 AM

Could you perhaps substantiate that claim? Because a stressed population with completely undifferentiated mortality would be a completely novel situation in biology; and I have a hard time accepting that to be the case on just your say-so. See, I can think of a number of selective forces right off the bat:There's selection for body size, or for using scant caloric intake to the most effective degree possible. Because people are starving.There's selection for disease resistance, because people are dying from diseases.I think that you're conflating "fitness" as a biological term with "fitness" in its common parlance. This is an error. Biologically speaking, it doesn't matter how well you eat and how much time you spend in the gym; you'll never be as "fit" as the 300-pound woman in the trailer park, feeding Doritos to her nine children. It's entirely natural; conspecific competition is an entirely natural selective force. Please note that I don't mean "natural" as in "proper", I mean natural as in "not artifical." This is the same sort of competitive resource allocation that occurs in almost every species.And there's simply no escaping natural sexual selection.

Nicely put, and on a related, more pragmatic note, it's pretty well-established that the industrial nations have considerably reduced population growth, due to the avaliability of birth control. So biologically speaking wealth is generally maladaptive.

but as the increase in wealth and tech improves the health and longevity of people in the west we need to reduce our population production to maintain a balance. In less developed societies that do not benefit from the west's tech and wealth tend to die sooner and in larger numbers thus the people there tend to, as far as we understand it over produce. The simple fact is due to the attrition on their numbers they need to produce many offspring just to stand still. What wealth and the technological advantages it brings means that each individual stands a far better chance of surviving to reproduce than those in less developed areas. Guess you say quality over quantity.This message has been edited by ohnhai, 01-06-2005 12:38 AM

Ok, but that's a meaningless distinction in biology. The fitness or "quality" of an individual is based on the quantity of their reproductive success.I mean I guess I kind of lost sight of your point. Maybe what you're saying is that, in the West, we somehow concentrate our genetic "quality" into fewer individuals than they do in Africa, but in addition to the disturbing overtones of that statement, as far as I'm aware, pretty much all the beneficial human mutations that are currently spreading through the world's population are coming out of Africa. For instance, HbC.

Ok the quality over quantity argument was a bad choice and does. if read in a certain light, lead you to disturbing conclusions (and ones which I find abhorrent) So I retract that phrase.I was simply trying to make the point that a drop in population growth must not be seen as being the mal-productive, as this is natures way of balancing out the population to a ‘sustainable level’. After all if we in the ‘developed world’ reproduced at the rate of those in ‘un-developed’ areas then we would have a serious problem on our hands. (Not that we don’t already). Where wealth comes into it is that despite the slow down in growth, each new child has a vastly better chance of reaching maturity and reproducing, than his/her counterpart in the ‘third world’.I guess what I was trying to say was where wealth wins as a strategy is because it created a ‘quality’ of life that is far better at bringing each child to maturity than a strategy that relies mainly on ‘quantity’ of life. In this regard I would much rather prefer the ‘Quality’ route for my self and children rather then the ‘Quantity’ route. However as each strategy does work they must bee seen as equally valid.

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Do you honestly think there's no selection going on in cases where large numbers of people are dying, in situations where environmental selection pressures are strongest?

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Population crashes generally do not distinguish in this regard. I remember reading a study of fox predation on rabbits in which the catch rate for foxes steadily claimed as the rabbit population dropped, until of course both fell off a cliff. They succeeded themselves to death, and under such circumstances there is little or no feedback between the actions of the individual fox and the food scarcity with which they are now confronted. Animals lucky enough to have been on the edge of fox territory would have been more likely to survive than those in the centre, but thats purely random and takes no account of any individuals capacities.What I meant by "no meaningful natural selection" is that we see deaths on a massive scale that do not emanate from natural sources. The impact on the individuals fitness from, say, a better metabolism, is lost if that fitness only makes them the last to die rather than the most likely to survive. Group membership is a much much greater determinant of "fitness" than anything genetic or chemical. Famine is strongly correlated with warfare - even if in a particular famine a particular individual survived and passed their superior metabolism on to their descendants I can't see that this would make any meaninful difference to the probability of those children surviving the next conflict-triggered famine.Surely for a fitness adaptation to become expressed in the population as a whole those more-fit individuals must in some manifest way benefit from their fitness such that their adapted genes become more widely distributed. I can see no reason for thinking that an improved metabolism is going to have a sufficient impact to improve the chances of the next generations survival if the source of the die-off is other human action.I don't refute the mechanisms of NS are still operational, but I don't think they are impactful enough to affect our survivability any more. I don't dispute and improved metabolism is an improved metabolism, I just don't think it matters. For large parts of the world, I think a blind paraplegic and a fully healthy person have pretty much the same odds of passing their genes to the next generation.This message has been edited by contracycle, 01-07-2005 09:00 AM

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Could you perhaps substantiate that claim? Because a stressed population with completely undifferentiated mortality would be a completely novel situation in biology; and I have a hard time accepting that to be the case on just your say-so.

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Hiroshima and Nagasaki. Or perhaps, what differentiation would you expect to have seen in Birkenau or Auschwitz.What makes an individual fit to survive in the modern world is wealth. All other survival criteria are subordinate to wealth, because wealth is a representation of the total impact we make upon our surroundings.

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I think that you're conflating "fitness" as a biological term with "fitness" in its common parlance. This is an error. Biologically speaking, it doesn't matter how well you eat and how much time you spend in the gym; you'll never be as "fit" as the 300-pound woman in the trailer park, feeding Doritos to her nine children.

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No I'm not. My point is this, what makes her fit? The fact that she has lots of kids, and even that these kids are likely to survive and procreate, does not imply superior fitness. All it implies is a merely sufficient adaptation to the prevailing environment to survive and procreate. But in her environment, an almost entirely human one, what determines her merely sufficient fitness is her membership of a wealthy society. If that suddenly ended, so would her fitness and that of her progeny. It can be inherited, but only socially.The rich live and the poor die. Ever since that began, ever since class divided societies first appeared, the individual fitness of the specific person has IMO become steadily less and less relevant to whether their genes make it to the next generation.Some estimates of Aztec human sacrifice run to as much as a quarter of a million people per year. I'm aware that these figures are contested and that 20,000 is more often mentioned. Still, this is a huge number for a bronze age society. Its a massive mortality rate, without any relevance to any natural selection factor. What determines fitness to procreate in this context is membership of the group doing the sacrificing rather than membership of the groups being sacrificed. IMO, human action has superceded NS to such a degree that it's effects on us are now trivial to non-existent. What matters far far more than anything else is social organisation, IMO.