Has natural selection been aborted?

Philosophy Forums Science, Technology, and Math
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Has natural selection been aborted?

I would say that natural selection, i.e. evolution, has taken a dramatic turn since the birth of human consciousness. Natural selection produced the human species and the human species has derailed natural selection. World wide the species that survive, including the human species, depends upon human created meaning and no longer upon natural selection.

We have become meaning creating creatures and have developed a high tech society that overwhelms the process of natural selection. The selection of what species will survive in the future no longer depends upon the process of natural selection but depends upon the process of human meaning creation.

Who am I? Of what value is my life? The child, when asking these questions, is saying that s/he wants to be recognized as an object of value. S/he wants to know how well s/he measures up as a hero.

Freud saw that the underlying foundation for these feelings and ambitions was the “utter self-centeredness and self-preoccupation, each person’s feeling that he is the one in creation, that his life represents all life” he tallied all this up and labeled it narcissism. Nietzsche saw this healthy expression as one of the “Will to Power” and glory.

[b]This represents the “inevitable drive to cosmic heroism by the animal who had become man.”

Culture provides the vehicle for heroic action directed toward strengthening self-esteem. The task of the ego is to navigate through the culture in such a way as to diminish anxiety, and the ego does this by learning “to chose actions that are satisfying and bring praise rather than blame…Therefore, if the function of self-esteem is to give the ego a steady buffer against anxiety, wherever and whenever it might be imagined, one crucial function of culture is to make continued self-esteem possible.

Culture’s task is “to provide the individual with the conviction that he is an object of primary value in a world of meaningful action.”[/b]

The cultural hero system whether religious, primitive, or scientific is “still a mythical hero-system in which people serve in order to earn a feeling of primary value, of cosmic specialness, of ultimate usefulness to creation, of unshakable meaning. They earn this feeling by carving out a place in nature, by building an edifice that reflects human value: a temple, a cathedral, a totem pole, a skyscraper, a family that spans three generations.”

[b]How does the American culture perform its task?

I claim that the maximization of production and consumption is the principal means for the satisfaction of self-esteem for its citizens. It is through the active participation as a member of a community that strives constantly to maximize the production and consumption of goods that the American citizen best satisfies his or her drive for “cosmic action”.

We are all captives of our cultural systems. Whether the cultural system dictates the stoning of one’s sister for destroying family honor or a system that finds cosmic heroism through a process that maximizes the rate at which we consume our planet.

Our culture is constructed from the meaning that we create. The future of our species and of all life is dependent upon our comprehension of our self and how we use that comprehension in developing a better meaning structure than we have done so far.[/b]

Quotes from The Birth and Death of Meaning Ernest Becker

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How would creating meanings change natural selection in any way? Organisms that survive and reproduce pass their genes from generation to generation. The genes of organisms that don’t reproduce die when the organism dies. How does this apply any less to humans than any other organism?

Now humans have changed and continue to change the environment. Human cultural environment is part of that. What is adaptive now is different than what was adaptive before humans modified things. But environmental change is part of the structure of natural selection. When change occurs it is the changed environment to which the organism is challenged to adapt.

If creating meaning helps individuals survive and reproduce, then it is adaptive and will be passed on to successive generations. Alternatively, creating meaning could either be maladaptive in which we can expect it to be extinguished, or an irrelevant byproduct of some other adaptive trait. In any case, natural selection continues unabated and unaborted.

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What is different now is technology. Technology is one of the meanings that we have created. Technology has given extraordinary power to ordinary people. With this power we determine what species live or die and with this power humans live longer and without death that would normally happen with less technology. It is quite possible that we will destroy our species and perhaps all life on this planet because we are not sophisticated enough to manage this great power that we have created.

What required millions of years humans can now destroy or achieve in years. Natural selection has no time in which to exercise control.

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Possibly, but only in the human species. Of course, we need to acknowledge that our awareness of natural selection has only been viewed through a narrow window. We can draw more accurate conclusions in 20,000 years or so, provided we haven’t anhiliated ourselves.

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Nope. Disease resistance is still evolving, as long as some people have more offspring than others natural selection takes place. Growing HIV resistance in Africa for example. Evolution in humans (modern) isn’t even slow, certain genetic variants have only recently swept through large populations.

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Think of natural selection as a law of nature that applies universally wherever there are living organisms. Organisms evolve differently in the Sahara Desert than they do on the Galapagos islands. But natural selection is operating in both environments. Likewise, natural selection operates in environments where there is no technology and in environments modified by technology. Technology changes the demands that the environment places on organisms. It doesn’t eliminate demands for adaptation. In modern technological society, individuals with certain traits, e.g. physical attractiveness, still have a better chance of having their genes represented in the next generation then individuals lacking those traits. Superior genetic fitness still result in increased representation in the next generation. Humans have the ability to effect massive extinction of species and in fact such an extinction is currently under way. This is having devastating global effect on biodiversity. But we would have to destroy every organism on the planet to stop natural selection. Fortunately, even our nuclear bombs probably lack that much destructive power.

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What required millions of years humans can now destroy or achieve in years. Natural selection has no time in which to exercise control.

We create our world of meaning and part of what we create is technology. Technology drives our world at an accelerating pace, far faster than natural selection has an opportunity to act out its selection process.

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EVEN TODAY NATURAL SELECTION IS MOLDING HUMAN POPULATIONS
Nauru is a remote Pacific atoll with a population of 5,000 Micronesians. Formerly, the Nauruans led energetic lives – fishing, subsistence farming – and they were slim and healthy. Then came colonization and phosphate mining; with these came wealth, imported caloriepacked food, sedentary lives, obesity, and, unhappily for this tropical paradise, diabetes. The incidence of diabetes mellitus shot up to 60%, an astounding statistic by world standards. On one of the wealthiest of the Pacific islands, the inhabitants have the shortest life spans! The same scenario is being played out in other parts of the world where life styles have changed drastically; for example, some Polynesians, American Indians, and Australian aborigines are similarly afflicted. Furthermore, an epi-demic of diabetes mellitus is anticipated as the “benefits” of civilization are brought to India and China.

Two questions must be answered: (1) Why is the incidence of diabetes mellitus only 8% among American junkfood-eating couch potatoes? Probable answer: [b]natural selection has already modified the American genotype by eliminating those who are supersensitive to diabetes mellitus under conditions of rich diets and sedentary lives. /b Why are modern populations still living under Spartan conditions so sensitive to diabetes in the first place? Possible answer: the so-called “thrifty genotype” hypothesis. In this view, the genotype that is sensitive to diabetes also confers survival advantages in societes where food supplies are meager and unpredictable. This genotype provides for a hair-trigger release of insulin for the rapid conversion of rare food gluts into body fat deposits that will sustain the individual during the next famine. Unfortunately, when rich food is continuously available, people with this “hairtrigger” genotype succumb to diabetes.

(Diamond, Jared M.; “Diabetes Running Wild,” Nature, 357:362, 1992.)

From Science Frontiers #82, JUL-AUG 1992. © 1992-2000 William R. Corliss

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27 February 2002
Natural Selection Pivotal In Molecular Evolution
by Kate Melville

Researchers from the University of Chicago have demonstrated that natural selection plays a much larger role in molecular evolution than anyone suspected. Their report, published in the February 28 issue of Nature, shows that about 25 percent of genes are evolving rapidly in response to competitive pressures. A second paper in the same issue confirms this discovery.

Although these papers focus on fruit flies, a previous report from the Chicago authors found a similar role for positive and negative selection on the human genome. Data from the previous study (Genetics, July 2001) allowed them to estimate the number of fixed “good” mutations, which distinguish humans from monkeys, and the number of residual “bad” mutations, genetic flaws that have piled up in the genome and are slowly being eliminated.

These papers directly conflict with the “neutral theory,” which has dominated genetic research since the 1960s. According to the neutral theory, many small genetic changes randomly occur, but the vast majority simply don’t matter. Fewer than one percent make enough of a difference that they are either embraced or expunged by natural selection.

“For several decades, the neutral theory has dominated thinking about evolution, but we haven’t had the technology to test it,” said Chung-I Wu, Ph.D., professor and chairman of ecology and evolution the University of Chicago and director of the study. “Now we are finding that, contrary to this accepted theory, Darwinian forces play a dominant role.”

To measure the importance of selection at the genetic level, Wu and his former graduate students Justin Fay, Ph.D., and Gerald Wyckoff, Ph.D., tallied the minute variations within each of 45 genes among flies of one species (Drosophila melanogaster) and contrasted them with the same genes from a different species (Drosophila simulans).

They found that competitive pressures were shaping about one out of four genes. Thirty-four of the 45 genes, or about 75 percent, showed no sign of natural selection. But, 11 genes, or about 25 percent showed evidence of ongoing rapid evolution. These genes contribute disproportionately to the total number of changes, says Wu.

Most of these genes, note the authors, are involved in processes such as disease resistance or sexual reproduction, areas where there is “continually room for improvement.”

By studying variation within human genes and comparing them with genes from old-world monkeys, Wu’s team has found that the survival of the fittest is just as active in humans. By comparing variation within the human genome and divergence from our ape ancestors, the researchers determined that about 35 percent of the accumulated changes were “good.”

“The proportion is shockingly high,” said Wu, “for someone like myself who grew up in the neutralist era.” It means one advantageous substitution has entered the human genome every two centuries since humans separated from monkeys 30 million years ago.

"Humans are getting better," Wu added, “but nobody is perfect.” Thirty to 40 percent of amino acid changes in human populations, the researchers report, are in fact slightly deleterious. They estimate that the average human carries about 500 harmful mutations, which are destined to be removed from the population by natural selection, but “transiently pile up before their exit.”

The assembly of fruit flies, the Nature paper shows, is no less shoddy.

These papers do not mean the end of the neutral theory, cautions Wu. But evolutionary geneticists familiar with the work expect these to be the first of a long string of papers that will rigorously test the theory and determine how much of existing genetic variation matters in the competition for survival.

The neutral theory, proposed by geneticist Motoo Kimura in 1968, was initially controversial but slowly gained near-gospel status. Before the advent of modern genetics, people studied evolution by looking at observable differences – such as variation in the shape of a bird’s beak – with a clear fitness value. In the 60s, researchers realized that underneath the few obvious differences between related species there were millions of DNA variations, far too many for natural selection to sort out.

So Kimura developed a mathematical framework to explain how evolution worked at the genetic level. He argued that the great bulk of DNA changes were neutral, biologically insignificant consequences of random mutation, and seldom if ever driven by natural selection.

“It was a simple, elegant, beautiful theory,” said Wu, “a nice, clean hypothesis that enabled us to make and test predictions based on statistical probabilities. But we are now reminded that biology is by nature very messy, a historical process that generates variety and accumulates multiple tiny aberrations to cope with changing environments.”

“These papers tell us how imperfect our genomes really are,” said Wu. “At the same time, they tell us how much improvement we have constantly been making, all by means of natural selection.”

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Human brains enjoy ongoing evolution
15:06 09 September 2005 by Mason Inman

The human brain may still be evolving, new research suggests. New variants of two genes that control brain development have swept through much of the human population during the last several thousand years, biologists have found.

The evolution of a large, complex brain has been the defining feature of the human lineage - although human brain size has not changed over the past 200,000 years. But it is not apparent whether the new genetic adaptations discovered in human brains have any effect on brain size, or intelligence.

What is more, not everyone possesses the new gene variants, potentially inflaming an already controversial debate about whether brains of different groups of people function differently.

“Whatever advantage these genes give, some groups have it and some don’t. This has to be the worst nightmare for people who believe strongly there are no differences in brain function between groups,” says anthropologist John Hawks of the University of Wisconsin in Madison, US.

Brain size
There are two new genetic studies that suggest the brain may still be evolving. Geneticist Bruce Lahn of the University of Chicago in Illinois, US, and colleagues analysed the sequences of two genes active in the brain - Microcephalin and ASPM. Both regulate brain size - people carrying a non-functioning mutant copy of these genes suffer microcephaly, where they have a normally structured brain that is much smaller than usual.

First, the researchers sequenced the Microcephalin gene found in 89 ethnically diverse people. The team found dozens of variants (or alleles) of the gene, but one particular set stood out. These alleles all carry a specific mutation that changes the protein the gene codes for.

This distinctive mutation is now in the brains of about 70% of humans, and half of this group carry completely identical versions of the gene. The data suggests the mutation arose recently and spread quickly through the human species due to a selection pressure, rather than accumulating random changes through neutral genetic drift.

Analysing variation in the gene suggests the new Microcephalin variant arose between 60,000 and 14,000 years ago, with 37,000 years ago being the team’s best estimate. The new mutation is also much more common among people from Europe, the Middle East, and the Americas than those from sub-Saharan Africa.

“Compelling evidence”
The team also sequenced the ASPM gene from the same original sample and again, among dozens of variants, found a defining mutation that alters the protein the gene codes for. Estimates are that the new variant of ASPM first appeared in humans somewhere between 14,000 and 500 years ago, with the best guess that it first arose 5800 years ago. It is already present in about a quarter of people alive today, and is more common in Europe and the Middle East than the rest of the world.

“The evidence for selection is compelling,” says population geneticist Rasmus Nielsen of the University of Copenhagen in Denmark. Yet it remains unclear yet how these genes work in healthy people. Many researchers doubt there is any mechanism by which nature could be selecting for greater intelligence today, because they believe culture has effectively blocked the action that natural selection might have on our brains.

Lahn and his colleagues are now testing whether the new gene variants provide any cognitive advantage. Natural selection could have favoured bigger brains, faster thinking, different personalities, or lower susceptibility to neurological diseases, Lahn says. Or the effects might be counter-intuitive. “It could be advantageous to be dumber,” Lahn says. “I highly doubt it, but it’s possible.”

Journal reference: Science (vol 309, p 1717 and p 1720)

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there is no need to separate human conscious action and natural selection. humans are still a part of nature, and from the perspective of other species of life, humanity is merely one more selection-pressure on their environment, forcing them to adapt to our presence or perish.

yes, our influence upon other species is quite a bit greater than many other environmental influences they must adapt to, but it is a different of quantity, not a fundamental difference-- only those species which can adapt themselves to the changes in their environment that humanity has created will survive, and will “deserve” to survive as defined by evolution itself. humanity is not an “unnatural” lifeform on earth or a “bad” selection-pressure; there is no good or bad when it comes to evolution. that which adapts, survives… that which does not, perishes.

of course, regarding humanity TO ITSELF, yes indeed we no longer are influenced very much by natural selection internally, within the species… there are just not very many environmental pressures which limit successful reproduction only to the most genetically “fit” individuals-- everyone mates, and in many cases, the less-fit mate successfully far more than the more-fit. one consequence of this is the progressive weakening of our gene pool, as well as uneven population dispersions. these are not all bad; certainly most people need some sort of corrective lenses to see accurately now, since we no longer rely on natural unaided vision to survive, but thats not really a problem, since we invented glasses and contacts and laser surgery… the fact that humanity CAN surpass selection pressures by purposefully altering its environment is not “unnatural” or “detrimental”, because for the same reason that the environment was altered sufficiently to produce the loss of selection, man can adapt himself and his environment to this new gap that he has created.

yet, in the long run, it remains to be seen how humanity will survive with his new-found conscious ability at environment manipulation. man still has not yet come to realise just the awesome power he has in his hands: everything evolves, and evolves according to its environment’s influences upon it; man, however, can control and direct his environment’s impact upon himself; THUS, man can literally DIRECT HIS OWN EVOLUTION. this is something we rarely realise, and the implications of which are lost on us. however, when you stop and really, truly think about it, its nothing short of amazing, divine, god-like: man creates himself. he is not a product of his “environment” in the sense of all other life: he is a produce OF HIMSELF.

someday we might be able to harness this as we should, and will ourselves into our future with confidence, intelligence, wisdom, awareness and foresight. but until we grow up enough to realise that we CAN do this, we will probably just continue to wander around aimlessly, purposelessly, without meaning or direction, suffering from the unintended and unforseen side-effects of our conscious control of earth’s environment.

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Technology may just make natural selection take different routes than it would otherwise have taken.

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I would liken the effect humans have had on the environment to the effect that plants first had on the environment. They pumped the atmosphere full of a new chemical(oxygen) that radically altered the environment and allowed different survival strategies. They cut off or made obsolete entire lines of variation that might have thrived without the rise of oxygen-producing plants. Oxygen was a volatile, dangerous chemical prone to destroying DNA and messing up chemical reactions, but the organisms that managed to adapt to oxygen were rewarded with a dangerous, volatile chemical to burn for energy.

I think the effect that humans have had is somewhat like that. It turns selection pressures on their heads, but ultimately it is not a game-ender for natural selection, it is a game-changer.

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That is an interesting view. However, I think that technology changes our environment too fast for any form of natural selection to take place, with the possible exception of the world of insects.

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No natural selection cannot be aborted like that. If we gained techs to produce our offspring by arbitrary cloning alone and then restricted the environment to such a degree that it was fairly selectively neutral then yes. As it is I still like women with long legs, big ass and large breasts. If that isn’t natural, it is at least selection. :slight_smile:

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The distinction between human and natural has no meaning in evolution. If lions go extinct because they can’t survive a world dominated by human culture, that’s still natural selection. In “survival of the fittest”, fittest is just defined as “that which survives.” It’s circular logic, but that’s why it’s absolute. Whether the environment is shaped by humans acting out of what we call meaning is irrelevant. So long as there’s such things as birth, death, reproduction and environment, there’s going to be natural selection.