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Are we subjected to Natural Selection?

antagonizer

antagonizer

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May 12, 2014
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Hello, I'm not to this site and I'm not sure if I'm posting at the right section or if there has been a topic of debate on this subject.

I have been wondering for a while: do you think humans are still subject to natural selection? Organisms are, over time, faced with changes in their environments. Considering the fact that humans have more control over the environment. For example, growing crops, make cures/medicines for diseases, etc. With this in mind, are we still subjected to natural selection?
 
Two schools of thought exist concerning the timetables that evolution occurs. 1) Darwinian - evolution occurs gradually over long periods of time. 2) Cataclysmic, such a advocated by Stephan Gould - evolution of a population is stagnate for long periods of time until a cataclysmic event occurs, rapidly changing the environment and suddenly the definition of fitness changes; think of floods or sudden temperate changes and how that would affect the environment.

The truth is that both schools of thought have merit.

The fact that we currently control our environment will have serious impact upon our species after a cataclysmic event occurs that takes this control away from us.
 
They haven't found the missing link between humanity's closest progenitor and us. I don't totally buy that humans became this advanced on their own, not until I see better evidence. We're subjected to natural selection now of course, but I don't think that's how we got here.
 
Fossils are the exception not the rule irt the geologic record. Environmental conditions must be just so for fossil preservation to occur. It is actually not surprising that so-called missing links have evaded discovery.
 
I think we are subject to the forces that drive natural selection, but are so well established we do not change from it. What would define the missing link to you foreinger? There are many fossils that at least share some traits with modern humans. Could not these qualify?
 
Kittycat5 said:
I think we are subject to the forces that drive natural selection, but are so well established we do not change from it. What would define the missing link to you foreinger? There are many fossils that at least share some traits with modern humans. Could not these qualify?
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I like how you place the perspective kitty.
I would only add that human existence has only occupied a very short time period compared to the time periods that Darwinian evolution would take place. Plus we sit precariously between the time of cataclysmic events that could accelerate the mechanisms of natural selection.

Imagine the world drowning due to the polar caps melting completely. Suddenly flipper babies would be the fittest form of humanity in terms of survival and reproduction.
 
I think a better question is why wouldn't humans be subject to the same biological processes that effect every other living organism on the planet? Just like most other multicellular life, we have pretty good but not perfect proofreading on DNA replication. The human genome is constantly changing with every new generation of people as a result. You can show genetic divergence among insular communities who avoid intermarrying with others (either through choice or isolation), as well.

Given that there are some individuals who seem to have drawn golden tickets in the genetic lottery and others that die before they leave the womb, I would say we are subject to natural selection just like anyone else. For instance, the "evolution" of white/dark skin. Humans in hotter, sunnier climates who had high melanin content in their skin to shield from UV damage were less likely to get skin cancer/chronic sunburns and hence had a slight advantage, whereas humans in less sunny climates could use resources otherwise used to make melanin for other purposes.
 
When it comes to human evolution (in the biological sense) I do think there is more to play than natural selection, sexual selection and so on..

Money / power (that has nothing to do with the biology of the individual / group) is a contributing factor to the likelihood of survival for that particular bloodline.. Medicine and the funds for it come to mind..

But generally yes.. Natural selection is still king of the evolutionary path.
 
rickolasnice said:
When it comes to human evolution (in the biological sense) I do think there is more to play than natural selection, sexual selection and so on..

Money / power (that has nothing to do with the biology of the individual / group) is a contributing factor to the likelihood of survival for that particular bloodline.. Medicine and the funds for it come to mind..

But generally yes.. Natural selection is still king of the evolutionary path.
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Actually money and power influence evolution less than you'd think. Most affluent families have relatively few children per generation. Population increases occur mostly in third world countries. The USA for example would have a declining population if it was not for immigration.
 
It should be noted that humanity is a very new species, and our entire history is very brief evolutionarily, and our post-agricultural history is utterly insignificant on evolutionary terms. Natural selection continues to operate on us, but not on a time scale that is usually visible, let alone salient.

ebola
 
ParappaTheRapper said:
If you were to say that one person, outlives another, through natural selection by physically outperforming;
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On a grand scale physical performance, as you call it, is not something that is passed down genetically. That is a very common misconception and it ain't how it works. If you cut your hand off with a Swiss Army knife, your offspring will not be born handless. We're talking about generations and generations of very slight changes that go unnoticed for more generations. Why do you have a tailbone? The tailbone aka coccyx has not much purpose, other than when it breaks, causes extreme pain and discomfort. Could it be that the apes which were our ancestors had tails? Oh the humanity!
 
Someone seems to be really awesome at every sport and has is intelligent enough to use technology to control the environment.
This said person then dies. His knowledge gone and physical gene traits eradicated from the gene pool. No more passing on but even though someone or a collection of people know how to over ride natural selection things still happen. Which ultimately is natural selection. We live quite freely now and pretty much at the top of the food chain but diseases can kill.

As long as organisms live us and everything else will always be subject to natural selection. I found this a few weeks ago anyway.

http://www.bbc.co.uk/news/science-environment-27023992

It's a hard one to explain...
 
I thought i'd seen a telly program where they compared oxygen processing in normal people with people who live at very high altitude and there were measurable genetic changes - this is natural selection isn't it?

And also as regards neo-darwinian vs lamarck, in 'epigenetics' aren't there little phosphate switches they've discovered on the back of the genome which modulate the action of the dna, and that this switching can be inherited? (i'm sure i saw something like that on a telly program)

There's also the (i think) related new epigenetic understanding of the action of 'junk dna' which could maybe allow other, more lamarckian affects to come into play? (correct me please i only vaguely remember it :)
 
ebola? said:
It should be noted that humanity is a very new species, and our entire history is very brief evolutionarily, and our post-agricultural history is utterly insignificant on evolutionary terms. Natural selection continues to operate on us, but not on a time scale that is usually visible, let alone salient.

ebola
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This.

And let's not forget about sexual selection. It's very much still alive and well.
 
Foreigner said:
They haven't found the missing link between humanity's closest progenitor and us. I don't totally buy that humans became this advanced on their own, not until I see better evidence. We're subjected to natural selection now of course, but I don't think that's how we got here.
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This is absurd. We know of about a dozen hominids that utilised technology etc. The Neanderthal was arguably more socially advanced than us in many ways, we just happened to out-compete them.
 
We are actually part neanderthal.. We have evolved alongside them, as them and out competed them all at the same time..

(Unless you're African)
 
The entire "missing link" idea is obsolete, and also dependent on a specific misconstrual of Darwinian evolution: missing links depend on evolution characterized as linear successions of organisms, moving from low to high complexity. Instead, the phylogenetic tree branches over time, any given 'generation' of organisms being cousins. And yes, the temporal period between the common ancestor between humans and chimpanzees is filled with now-extinct intermediate species.

ebola
 
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