the course of evolution

[ArkiStan]

Has modern civilization begun to alter the course of evolution now that there are so many new factors, totally unrelated to how fit a species is to survive, that seem to be affecting what was considered before "natural" genetic selection. In more cases than ever, the likelihood of being hunted/neglected is now largely determined by arbitrarilly established sociocultural values (whimsical fashion trends, oil spills, sudden sprawls of development, etc).

Is there a degeneration taking place, or is the concept of evolution (in its traditional academic meaning) simply going through a little random mutation of its own?

[Merlin]

I think so. We have gotten to the point where we adapt our enviornment to us rather than the other way around. Take the old evolution exapmle: To get the good food from the top of the tree the animals with the longer necks thrive. But humans....well we just build a ladder.

[welfareloser]

i think about this occasionally... for the most part, i think that things that took 10s of 1000s of years to evolve will take us at least 1000s to f*** up. but there are some things that we could potentially f*** up much faster. i dunno... we'll have to wait and see. i can imagine a future where ppl who would have died without medical intervention would not be allowed to reproduce.

[Jeffbx]

How about the elimination of a species? I'd bet that could have a pretty profound impact in the food chain & possibly the overall ecology of an area. But I suppose it's hard to know what the evolutionary impacts of that would be, especially in the short term.

Take the dodo bird for example - how would Mauritius & the other species there be different today if they weren't killed off? It's only been a few hundred years, but I bet there are some profound differences in the other inhabitants there by now.

[zippyjuan]

For one example, the stupid gene is allowed to flurish. People who would have been incapable of supporting themselves or would have killed or maimed themselves through dumb mistakes are allowed to survive thanks to improved safety laws. This allows them to survive and pass on the trait. A thousand years ago they would have probable perished before having offspring.

[Merlin]

Human evolution

Sugars and spice
Mar 9th 2006
From The Economist print edition

More evidence that people are still evolving


ALL species change the environment, but few have changed it to the extent that humanity has since farming was invented 10,000 years ago. In nature, however, such change goes both ways. Organisms are genetically adapted to their circumstances by evolution, and if the circumstances change, the genes should respond in their turn. Which is just what Benjamin Voight and his colleagues at the University of Chicago have found, in a piece of research published in PLoSBiology.

Dr Voight drew his raw data from the International HapMap Project. This project is designed to look at differences (known as haplotypes) between human genomes around the world. The team selected three groups for investigation: the Yoruba of Nigeria, East Asians (defined as Chinese and Japanese), and Europeans.

A lot of the differences between genomes are single nucleotide polymorphisms (SNPs), the technical name for stretches of otherwise-identical DNA that differ between individuals in a single genetic “letter”—that is, in one of the pairs of chemical bases in which the message of the genes is written. Most SNPs are there at random, making little difference to the way the genes operate. That is because the ones that do matter either disappear (because they are bad for survival), or become ubiquitous (because they are good for survival). But if a beneficial SNP has emerged recently, then it might be possible to catch it in the act of spreading. And that is exactly what Dr Voight and his team think they have done.

During sexual reproduction, matching chromosomes from mother and father exchange genetic material to create new chromosomes. Over the millennia, this leads to a thorough mixing of the genetic material. But Dr Voight reasoned that if a SNP is spreading rapidly through a population it will carry its neighbours with it, because there will be less time for the process of genetic exchange to separate it from those neighbours. The way to find recently evolved changes is therefore to look for them in long blocks of DNA that are more frequently identical in different individuals than they ought to be.

The team identified several hundred genes that had undergone recent selection in at least one of the populations being studied. Some were not surprising. Genes involved in the generation of sex cells, and in fertilisation, are known from other work to have strong selective pressures on them, and those pressures clearly continue in modern humans. Nor was it much of a shock to discover selection, in Europeans, for changes in four skin-pigmentation genes known to be involved in reducing melanin content.

Perhaps the most intriguing results were those connected with food metabolism. The gene for alcohol dehydrogenase is undergoing selection in Asia, as is that for processing sucrose (table sugar). Meanwhile, the genes for processing two other sorts of sugar, lactose (found in milk) and mannose (found in some fruit) are changing in Europeans and Yoruba respectively. Fatty-acid metabolism, too, is changing in all three populations. And Europeans are having the toxin-disposal systems in their livers modified.

Some brain genes are also changing, including two that control the size of brains, and two involved in susceptibility to Alzheimer's disease. And three genes that control bone growth have been modified in Europeans and East Asians, while the Yoruba have seen changes in genes that control hair growth.

What all this means in practical terms is not yet clear—though it could help to explain the incidence of certain diseases as incompletely assimilated responses to recent environmental changes. But it does, once and for all, knock out the idea that mankind, by tailoring his environment to his needs, has somehow stopped evolution in its tracks.

[ArkiStan]

if the circumstances change, the genes should respond in their turn....

(snip)

What all this means in practical terms is not yet clear—though it could help to explain the incidence of certain diseases as incompletely assimilated responses to recent environmental changes.

I'm not doubting the facts in the article. I think it's very interesting, but it seems like this author is suffering from a serious misconception about the very fundamental laws of evolution. Speaking strictly from a classical Darwinian point of view, there is no such thing as an entity actively "adapting/responding to its environment." There are only random mutations. Due to natural selection, only the entities that were fortunate enough to have mutated in a way that increased their likeliness for survival do so. Thus, in the end, when all the unfortunate are weeded out, it seems as though the survivors have "adapted" to their circumstances, but that is not the case.

If the author used the word "adapt" in a passive rather than active sense, then nevermind.

[wung]

I'm not doubting the facts in the article. I think it's very interesting, but it seems like this author is suffering from a serious misconception about the very fundamental laws of evolution. Speaking strictly from a classical Darwinian point of view, there is no such thing as an entity actively "adapting/responding to its environment." There are only random mutations. Due to natural selection, only the entities that were fortunate enough to have mutated in a way that increased their likeliness for survival do so. Thus, in the end, when all the unfortunate are weeded out, it seems as though the survivors have "adapted" to their circumstances, but that is not the case.

If the author used the word "adapt" in a passive rather than active sense, then nevermind.

a very good and clarifying point!!!

[Cubsfan]

Due to natural selection, only the entities that were fortunate enough to have mutated in a way that increased their likeliness for survival do so. Thus, in the end, when all the unfortunate are weeded out, it seems as though the survivors have "adapted" to their circumstances, but that is not the case.

If the author used the word "adapt" in a passive rather than active sense, then nevermind.
This is one reason why I think that human evolution is slowing/stopping. We're smart enough to cure things now. People live longer and don't die of things that they used to (small pox?), so we never will evolve to fight these types of diseases.

You could also look at it that we're taking control of our own evolution with things like prosthetic limbs, and even things that start to blur the line between human and computer, such as implants.

[Houdini]

I'm not doubting the facts in the article. I think it's very interesting, but it seems like this author is suffering from a serious misconception about the very fundamental laws of evolution. Speaking strictly from a classical Darwinian point of view, there is no such thing as an entity actively "adapting/responding to its environment." There are only random mutations. Due to natural selection, only the entities that were fortunate enough to have mutated in a way that increased their likeliness for survival do so. Thus, in the end, when all the unfortunate are weeded out, it seems as though the survivors have "adapted" to their circumstances, but that is not the case.

If the author used the word "adapt" in a passive rather than active sense, then nevermind.

:stupid: The mutations are generally random, as far as we can tell. However, certain outside factors can influence how random the changes are. Radiation exposure, chemical exposure, drug exposure, and who knows what else may change the genetics of a gamete. Classical Darwinism is a good model, but it may have some caveats that we haven't explored sufficiently.


This is one reason why I think that human evolution is slowing/stopping. We're smart enough to cure things now. People live longer and don't die of things that they used to (small pox?), so we never will evolve to fight these types of diseases.

You could also look at it that we're taking control of our own evolution with things like prosthetic limbs, and even things that start to blur the line between human and computer, such as implants.

I don't think it's stopping at all. Sure, we can cure some things now, and people are living longer due to better nutrition and medical care. Life expectancy has increased tremendously from 100 years ago. That's a huge leap in evolutionary terms.

Not everyone died of smallpox, so some people did fight that disease successfully. For some reason, a small percentage of people seem to be immune from HIV as well. Exploring how/why this occurs is pretty cool.

I think we'll continue to evolve indefinitely. People 5000 years from now will likely be much different from those today. I've thought about this a lot, and I wonder what it would be like to go back, say, 2000 years to see what people looked like (in life...not as skeletons or mummies) and how they responded to what diseases. While I'm there, I'd expect to become infected with some disease unknown to us now. :shrug:

[ArkiStan]

The mutations are generally random, as far as we can tell. However, certain outside factors can influence how random the changes are. Radiation exposure, chemical exposure, drug exposure, and who knows what else may change the genetics of a gamete. Classical Darwinism is a good model, but it may have some caveats that we haven't explored sufficiently.

I totally agree. Genetic mutation is definitely not like it was in the good ol' days. However, I think the basic fundamentals of classical darwinism is still in good enough standing that the author's possible misunderstanding was critical. It's probably the most common misconceptions about evolution.

[molecularfire]

:stupid: The mutations are generally random, as far as we can tell. However, certain outside factors can influence how random the changes are. Radiation exposure, chemical exposure, drug exposure, and who knows what else may change the genetics of a gamete. Classical Darwinism is a good model, but it may have some caveats that we haven't explored sufficiently.



I don't think it's stopping at all. Sure, we can cure some things now, and people are living longer due to better nutrition and medical care. Life expectancy has increased tremendously from 100 years ago. That's a huge leap in evolutionary terms.

Not everyone died of smallpox, so some people did fight that disease successfully. For some reason, a small percentage of people seem to be immune from HIV as well. Exploring how/why this occurs is pretty cool.

I think we'll continue to evolve indefinitely. People 5000 years from now will likely be much different from those today. I've thought about this a lot, and I wonder what it would be like to go back, say, 2000 years to see what people looked like (in life...not as skeletons or mummies) and how they responded to what diseases. While I'm there, I'd expect to become infected with some disease unknown to us now. :shrug:
Careful. 2000 year old STD strains are a b$#ch to treat.

[Houdini]

Careful. 2000 year old STD strains are a b$#ch to treat.

EEK.. Didn't think of that. Note to self - bring some vanco.

[molecularfire]

Actually... if you think about it penicillin would work better. Better spectrum, more efficacious and pretty much a 0% resistance rate.

[Houdini]

Actually... if you think about it penicillin would work better. Better spectrum, more efficacious and pretty much a 0% resistance rate.

True. Vanc would be overkill. I'll just bring along some penicillin. Cheaper too. Now where did I put that #$#@ flux capacitor????

[attgig]

I think so. We have gotten to the point where we adapt our enviornment to us rather than the other way around. Take the old evolution exapmle: To get the good food from the top of the tree the animals with the longer necks thrive. But humans....well we just build a ladder.

actually, we cut down the tree to build the ladder, and eat some canned, out of the labratory crap.

[zenbooty]

We will all be Zerg in the end. :D