Have humans stopped evolving?

[none123]

I am wondering if we as a species have stopped evolving due to advances in modern medicine. It seems someone 200+ plus years ago that wouldn't have lived long enough to pass on their genes, can now readily do so. Used to have to be strong enough or smart enough to be able to hunt and provide for your family, and free of genetic or other diseases. But now any moron can procreate, most diseases can at least be treated to let them live long enough, that now it isn't a survival of the fittest. In fact, it seems some religions encourage their members to have large families (catholics, mormons, etc) so the unintelligent seem to pass on there genetic material faster than the intelligent. So maybe even devolving.  What are your thoughts?

[pinkocommie]

I am by no means an expert, but from everything I've read people largely believed that human evolution had slowed or stopped until we started studying the human genome (and even more recently, the Neanderthal genome and how it relates and intertwines with the human genome), only to find that it is entirely possible that we are riding the beneficial wave of a population explosion which leads to more variations and more chances for those variations to be selected for and driven toward fixation.  There are lots of theories out there, but the most recent information I've read tends to lean toward humanity rapidly evolving as opposed to not evolving or evolving very slowly at this time, especially when compared to the rate of pre-stone age human evolution.

At any rate, I'm guessing squid or the other brilliant people here can answer this question far more clearly and accurately than me, but here are some links that might be of use in the meantime -

http://www.dailygalaxy.com/my_weblog/2009/10/the-past-5000-years-mark-a-new-epoch-in-human-evolution-the-weekend-feature.html
http://en.wikipedia.org/wiki/Human_evolution#Recent_and_current_human_evolution
http://www.sciencedaily.com/releases/2010/01/100111102538.htm

[Tank]

The simple answer is no, humans have not stopped evolving. The selection pressures have changed which means what comes out of the evolutionary process will be shaped by different things.

[joeactor]

The simple answer is no, humans have not stopped evolving. The selection pressures have changed which means what comes out of the evolutionary process will be shaped by different things.

Agreed.

It's easy to confuse evolution with some sort of advancement.

After all, with my eyesight, I'd have probably been some lion's dinner by now... not to mention diseases and other pressures that no longer exist.

That's the wonder of evolution.  It's based on the environment that the creature is in, not on any plan or goal...

... but I will say that we may be weakening as a species if the technology is ever removed from the equation...

[Tank]

I have three grown up kids. The least academic is the one expecting a baby and will probably have another. The most academic will probably not reproduce, he is way too selfish. The other is in between regarding academic achievement and I'd say it's 70/30 she will reproduce.

[Dretlin]

I am wondering if we as a species have stopped evolving due to advances in modern medicine. It seems someone 200+ plus years ago that wouldn't have lived long enough to pass on their genes, can now readily do so. Used to have to be strong enough or smart enough to be able to hunt and provide for your family, and free of genetic or other diseases. But now any moron can procreate, most diseases can at least be treated to let them live long enough, that now it isn't a survival of the fittest. In fact, it seems some religions encourage their members to have large families (catholics, mormons, etc) so the unintelligent seem to pass on there genetic material faster than the intelligent. So maybe even devolving.  What are your thoughts?

A former biology teacher told me our appendix, is getting smaller overtime. Do not quote me on that, I am merely dragging up a weak memory. Could be true, could not be. I would need to research it and question an expert on the subject.

[Kylyssa]

I have three grown up kids. The least academic is the one expecting a baby and will probably have another. The most academic will probably not reproduce, he is way too selfish. The other is in between regarding academic achievement and I'd say it's 70/30 she will reproduce.

I find it odd, that many people believe that to not reproduce is selfish.  World population is growing and thousands of people die in misery each day.  Many selfish people reproduce far beyond replacement level.

[Martin TK]

There may be less physical evolution than mental evolution today than in the past; however, there is certainly going to be physical changes in mankind as the need to adapt to changing surroundings continue.  The idea of survival of the fittest being into play, might be changing, and so the adaptations of evolving faster, stronger, etc may be something of the past due to the advances of medicine, diet, etc.  The problem with "seeing" evolution is the amount of time for one small change to adapt to the environment.  Evolution isn't likely to come from one generation to the next, not physically anyway.  I do not think that nature can simply stop evolving, unless the species is destined to become extinct.

[Tank]

I have three grown up kids. The least academic is the one expecting a baby and will probably have another. The most academic will probably not reproduce, he is way too selfish. The other is in between regarding academic achievement and I'd say it's 70/30 she will reproduce.

I find it odd, that many people believe that to not reproduce is selfish.  World population is growing and thousands of people die in misery each day.  Many selfish people reproduce far beyond replacement level.

I'm just making an observation about my son, I can't see him changing a nappy  

[Martin TK]

I have three grown up kids. The least academic is the one expecting a baby and will probably have another. The most academic will probably not reproduce, he is way too selfish. The other is in between regarding academic achievement and I'd say it's 70/30 she will reproduce.

I find it odd, that many people believe that to not reproduce is selfish.  World population is growing and thousands of people die in misery each day.  Many selfish people reproduce far beyond replacement level.

I'm just making an observation about my son, I can't see him changing a nappy  

I don't see anything wrong with people electing NOT to have children, however, it is proven that people who achieve higher academic levels do tend toward fewer children, or no children at all.  IF I had waited until I finished my doctorate, I'd probably have opted not to have children, thankfully, I had mine very early in my marriage and still had time to pursue my academic love.  Just my humble opinion.

[Tank]

I don't see anything wrong with people electing NOT to have children, however, it is proven that people who achieve higher academic levels do tend toward fewer children, or no children at all.  IF I had waited until I finished my doctorate, I'd probably have opted not to have children, thankfully, I had mine very early in my marriage and still had time to pursue my academic love.  Just my humble opinion.

Why people don't have children is the combination of selection pressures, the result is selection, the result of that will be evolution, where that will lead we won't see, as we'll all be dead.

[Squid]

Yes, we are still evolving and this has been shown empirically by examining human genetics.  A study published in PLoS Biology showed recent selection on the human genome.  The only way that evolution stops is if certain criteria are met, one of those being no mutation - I don't see this being stopped anytime soon even with our most advanced technology right now.  The criteria so that no evolution takes place:

* The population must be infinitely large (or at least large enough to overcome any contribution by drift).

* Mating must be completely random.

* There must be no selection taking place.

* There must be no mutations.

* There must be no gene flow.

[SSY]

Well, it's certainly true that IQ and fertility (at least, realised fertility) are negatively correlated, which seems a shame to me. Other selection pressures like partner selection and the like will have an effect on the overall abundance of certain genes in the population, so in that sense evolution is going to continue, but we probably wont be evolving third arms. I consider artificial genetic engineering to be much more likely as the future agent of change.

I also agree with Kylyssa regarding having children and selfishness btw.

[Tanker]

Evolution is a totay neutral process. Not all changes are positive to the recipient. Better medicine just means we probably evolve a less effective immune systems. Evolution never stops for any reason but extiction.

[Sophus]

Our heads are shrinking! Seriously... the human cranium is getting slightly smaller which may mean we're packing more brain power in less space. Also I've been told, though I don't know how reliable the source, that the armor made to fit the largest warriors from around 500 years ago is can now only be suited for rather small men today.
I always hear that crocodiles or great white sharks have "stopped" evolving.