Have humans weakened natural selection's potency?

[A Tripolation]

Sorry if this question has been asked. I did a search for it and nothing came up.

 

Anyways, what I mean is that what with the advent of medicine and technology, we keep people alive that wouldn't have lived (or reproduced) a few decades ago, let alone a few centuries ago.

 

I have a very limited understanding of biology, so I was wondering if we were "controlling" natural selection to an extent. People with genes that are "unfit" for survival usually survive in the developed countries. Some even have children and pass on their bad genes.

 

Is this sort of thing happening, or do I have a misunderstanding of the fundamentals of natural selection?

 

Also, taking the concept of evolution to the extreme, will humans progressively get smarter or gain more physical advantages? Is there a "terminal velocity", as it were, for evolution? A life form that is perfect in every way for its evironment?

[Mokele]

Genes are neither bad nor good - there is no such thing as an inherently unfit gene unless it's purely lethal. Environment determines fitness. A shaggy coat on a dog is fit in Alaska, unfit in Alabama. By inventing cures and treatments, we've changed the selective landscape, rendering previously 'unfit' genes 'fit'.

[iNow]

In fact, one could argue that natural selection itself has given us medicine and technology. While I think it allows for less capable humans to survive, the change itself was brought about by selection, essentially shifting the selection pressure toward other traits or characteristics. Also, try to remember that there is no goal or intention with selection, and that the environment rules, so there is no "terminal velocity." As Mokele said, a trait which works in one environment is detrimental in another.

 

Perfection is a path, not a destination.

[dr.syntax]

In my opinion, our gene pool is being degraded. Many unwholesome genes are entering the gene pool and getting passed on. Your understanding of the fundementals of natural selection are correct in my opinion. No amount of rationalization is going to change that. Natural selection simply does not care about any of us people or any other organism. One of those facts of life in this indifferent Universe. That does not mean that I don`t care or am indfferent to the suffering of others. I do care and help others when I feel like it. ...Dr.Syntax

Edited September 9, 2009 by dr.syntax
clarification

[foodchain]

In my opinion, our gene pool is being degraded. Many unwholesome genes are entering the gene pool and getting passed on. Your understanding of the fundementals of natural selection are correct in my opinion. No amount of rationalization is going to change that. Natural selection simply does not care about any of us people or any other organism. One of those facts of life in this indifferent Universe. That does not mean that I don`t care or am indfferent to the suffering of others. I do care and help others when I feel like it. ...Dr.Syntax

 

Have you ever questioned if our social nature from an evolutionary standpoint has developed possibly that desire to be nice or help people? I am not sure but I think being a murderer today reduces fitness to some extent:confused: Natural selection can account for a lot of things, I mean is drunk driving and accidents related to it natural selection? What about language, is that something that came about via selection, or anything that humans do or are capable of? What will our "specie" happen to look like in eons? If we make a lawful society that only cares for nice people, wont be be indifferently selecting against the rest? What is fair really?

 

Going past all of the above philosophy you can use along with biological stuff, I just overall think its mildly error prone to attribute anything to natural selection except for the scientific(biological) reality it produce.

[dr.syntax]

I agree with much of what you said. Caring for and helping each other has real benefits for our species and others. Wolves,lions,bison,prairie dogs,certain birds,beavers,baboons and so many others form co-operative behaviors that help in the survival of thier species. But unlike those species, our technology now allows for the survival of those with severely debilitating traits that under the usual conditions of natural selection would never reproduce. ...ds

[iNow]

I know. Like juvenile diabetes. I, for one, am rather thankful for medicine, and find your words hateful and myopic.

 

 

Now, can you guys please STFU and stop posting to this thread unless you have something relevant to contribute to the questions presented in the OP? Thanks.

[Sisyphus]

Yeah, and the ability to walk on land and in the air meant that individuals could survive who were poorer and poorer at extracting oxygen from seawater, until we lost the ability completely! Degradation!

 

Seriously, though, there's no such thing as "de-evolution" or whatever. The environment has changed, that's all. That's not a "rationalization," that's understanding the definition of natural selection.

[A Tripolation]

Oh, I see what you and Mokele are saying, iNow.

I just guess Im thinking more of "unfit" as in the event of an apocalyptic situation or other things where anything less that perfect health would make you end up dead.

 

But I was also thinking in terms of "perfection" as creatures that are practically unstoppable. Take the Aliens in the "Alien" movies for example. Even with firearms, humans would be no match for them, intellectually of physically. A creature such as that seems to be almost a penultimate version of life right? Perfectly Evolved?

[insane_alien]

no, just a better predator than us.

 

there is not such thing as 'perfectly evolved'

 

there is no perfect, there is no ultimate goal

[Sisyphus]

Oh, I see what you and Mokele are saying, iNow.

I just guess Im thinking more of "unfit" as in the event of an apocalyptic situation or other things where anything less that perfect health would make you end up dead.

 

But that would be a huge change in the environment. That's like saying, if the oceans dry up, whales wouldn't stand a chance!

 

But I was also thinking in terms of "perfection" as creatures that are practically unstoppable. Take the Aliens in the "Alien" movies for example. Even with firearms, humans would be no match for them, intellectually of physically. A creature such as that seems to be almost a penultimate version of life right? Perfectly Evolved?

 

No. There is no more or less evolved. If there is any "measure" of success, it's the ability to survive, reproduce, and pass on your genes (in whatever environment you happen to live, bearing in mind that you yourself are a part of your environment), not the ability to beat me up on a spaceship. Although in certain specific situations (like being trapped on a spaceship with the aliens from Alien), the latter would probably help with the former.

[A Tripolation]

Hmm...I certainly see what you all are saying. Ability to survive in your environment determines how well evolved you are. Makes sense.

 

But, like with my Alien example, if they were to appear on Earth, they would be "more well-evolved" as they would flourish in this environment (all of Earth) by wiping us out and making this their home, right?

The playing field would be level, and the surviving species would be the better evolved, right (which I'm almost certain would be the Aliens)? There would be no co-habitation or anything like that, so an altruistic relationship is ruled out.

 

Thoughts? I'm probably still way off and I apologize for it.

[iNow]

Instead of thinking about them as "better evolved," it may help to think about them as "better adapted." That is really the key. Some will be able to exploit the environment better than others due to their adaptations.

 

As for co-habitation, that really depends on the animal. If they are aggressive and kill competitors, that would make it difficult for others to survive. If they used all of the resources like food and water, and left none for other animals, that too would make it difficult to survive. If they brought some sort of illness or disease, that would make it difficult to survive.

 

The idea is that you survive if you are properly adapted to your environment (whether that be the land, the air, the predators, the diseases, etc.), and are able to procreate and push genes into the future that share your advantageous adaptations (so they, too, can thrive in that environment).

[Sisyphus]

That would make the aliens an invasive species, creating a major change on Earth (basically a third environment different from the ones either species had been evolving in). I don't know what the terminology would be, but I don't think you'd call the aliens "superior." Unless an introduced bacterium that wipes out a human population is also "superior" to the humans it wipes out. I guess in a way it would be, as the bacterium survived and the humans did not.

[JillSwift]

I'd just like to add: Our ability as a species to modify our environment and our selves to suit ourselves is itself an adaptation.

 

It is what allows our species to move from environment to environment without having evolved into the new environment. (And the few evolved/phenotype adaptations are very minor, such as the melanin content in the skin.)

 

So, in essence, the reason genes stick around that would have otherwise been selected out is because we have adapted to be able to adapt in ways other than the genetic/phenotype level.

 

Way cool.

[A Tripolation]

Ok, well does anyone know what the proper term would be? I think "superior" is a good term Sisyphus. The Aliens are prectically "superior" in every way.

 

In a way, if the Bacteria is able to "overpower" our immune systems and all of our medicine (which also entails overpowering our greatest medicinal minds, our greatest technologies, and medicines), then yes, I think it should be considered "superior" as well.

 

And to JillSwift, that is an AWESOME point. Humans have adapted an ability to rapidly adapt.

[Sisyphus]

"Superior in every way?" But what's the criteria for that, and how are those criteria justified? This is the point. There are no inherent objective criteria for "superiority." What you're talking about are qualities that you subjectively value.

[JillSwift]

Ok, well does anyone know what the proper term would be? I think "superior" is a good term Sisyphus. The Aliens are prectically "superior" in every way.

Ripley kicked thier butts. Twice! Then died, came back, and kicked thier butts again!!!

 

Evolution is not about superiority. It's about adaptation - and adaptation is nothing more than natural selection at work. Several species can fit the same environmental niche, each having adapted to it differently. Take spider monkeys and sloths. Both are exceptional tree-climbers. Can either said to be superior in their niche? Only as a value judgement. Objectively, each species simply has a different method for handling mobility in branches.

 

In a way, if the Bacteria is able to "overpower" our immune systems and all of our medicine (which also entails overpowering our greatest medicinal minds, our greatest technologies, and medicines), then yes, I think it should be considered "superior" as well.

Again, that's subjective criteria. Your hypothetical bacteria would simply have adapted to a new environment. Were it doing us harm in the process (not a given, BTW) then we simply have a changed environment in which our species might adapt to, or might fail to adapt to.

 

And to JillSwift, that is an AWESOME point. Humans have adapted an ability to rapidly adapt.

Thankies

[A Tripolation]

"Superior in every way?" But what's the criteria for that, and how are those criteria justified? This is the point. There are no inherent objective criteria for "superiority." What you're talking about are qualities that you subjectively value.

 

I'm thinking more along the lines of direct combat...or even guerilla tactics. The "Aliens" are superior in that they are stronger than us, faster than us, their blood is acid, and they could rip us to shreds in a matter of seconds.

 

But now, I see that humans would have many "superior" adaptations over aliens, such as our hands and tools and weapons that the aliens do not have, and could not even control.

 

But I would think that being stronger and smarter than your competitors would be a universally valued trait. Aside from the microbial world, could you give me an example of where being stronger and smarter ISN'T an advantage?

---

Merged post follows:

Consecutive posts merged

Ripley kicked thier butts. Twice! Then died, came back, and kicked thier butts again!!!

 

To that I say, Action Movie

[CharonY]

But I would think that being stronger and smarter than your competitors would be a universally valued trait.

 

Nope. The only measure of fitness is the amount of offspring you create that in turn are able to create offspring. Also you will have to consider that direct competitors are usually those that try to fill the same ecological niche and not those that hunt each other. If an organism utilizes the niche more efficiently by and creates more offspring they are fitter, regardless whether they are stronger or smarter. Cockroaches are a prototypical example. They are hardly the smartest critters on earth and clearly do not overpower much, but if they beat the heck out of a lot of animals in filling (urban) ecological niches.

[Sisyphus]

And just talking about humans, big brains are very expensive. They're energy hogs, and they take decades to fully develop. Human beings are still dependent on their parents long after most other animals would have been grown and having offspring of their own. Everything has a cost, and things like intelligence and strength are only net advantages up to the point where they contribute to having more surviving offspring sooner more than they hinder it.

[mattydee]

Another thing to consider is that these hypothetical aliens wouldn't have "paid their dues" on earth, meaning that they would have evolved in a completely different environment than us.

 

So something like a common cold or even a bacteria living in a symbiotic relationship with humans could wipe them out completely, assuming the parasite takes to this new host and said host has evolved an immune system that was meant to deal with an entirely different set of parasites and so is defenseless in this case.

 

This is the "War of the Worlds" defense

[Cap'n Refsmmat]

The trouble with the idea that we've "weakened" natural selection is that it assumes natural selection weeds out disease and weakness and does nothing else. What we as a species have done is reached the point where disease and weakness does not stop us -- you might say we've evolved an immune system so clever that it uses complex machinery and medications extracted from its environment to support the body.

 

Why should what our intelligence accomplishes be regarded differently than what the rest of our body does?

[Mr Skeptic]

I have a very limited understanding of biology, so I was wondering if we were "controlling" natural selection to an extent.

 

Yes, we've changed the environment we live in. The rules are different. You could say the selection is partly "artificial selection" now. I guess artificial selection is kinda like sexual selection, it isn't necessarily based on adaptation to the environment itself, rather to individuals in the environment.

 

People with genes that are "unfit" for survival usually survive in the developed countries. Some even have children and pass on their bad genes.

 

Oh, more than that, our wealthy and smart people are having less children than others. People were worried that this would cause trouble but it doesn't seem to have. As for "unfit" genes, they may soon become an endangered species due to the advent of genetic profiling (cheap genetic profiling coming to a store near you any year now).

 

Is this sort of thing happening, or do I have a misunderstanding of the fundamentals of natural selection?

 

Also, taking the concept of evolution to the extreme, will humans progressively get smarter or gain more physical advantages? Is there a "terminal velocity", as it were, for evolution? A life form that is perfect in every way for its evironment?

 

Yes. We can outrun cheetahs, out-fly birds, out-reach giraffes, out-dig moles, out-smart primates, out-shoot archer fish, out-build termites and beavers, out-farm leafcutter ants... OK so we cheat. But while evolution tends to improve species, at its slow pondering pace, it can also go backwards or in circles, since it follows immediate adaptation to a given environment. Technology, on the other hand, can anticipate problems (sometimes), progresses only forward (or I would like to think so), and in any case is far more rapid. My prediction is that, unless something drastic happens, our genetics will soon have more to do with technology than evolution.

[Baby Astronaut]

Instead of thinking about them as "better evolved," it may help to think about them as "better adapted."

 

I'm thinking more along the lines of direct combat...or even guerilla tactics. The "Aliens" are superior in that they are stronger than us, faster than us, their blood is acid, and they could rip us to shreds in a matter of seconds.

Instead of better adapted, could it be more accurate to say they're better equipped? As it'd have little dependence on environment then, and more in (relative) fighting or invasive abilities.