Have we stopped ourselves evolving?

[Bob A Job]

I posed this question a while back on answerbank, but got bombarded by religous nuts going on about god (pehaps because at the time there was not a science topics).

 

Have we stopped evolving?

We have no natural predators, we cure the sick, and have developed ways of dealing with weather & natural disastors. Provided we dont blow ourselves up will we stay like this indefinately?

Because we cure the sick are we polluiting our bloodline with disease and weakness (Puts on moral bulletproof vest) are we de-evolving?

 

Discuss.

[NetSquirrel]

With our current technology, human evolution is only occurring at a tiny fraction of its "normal speed".  There is still genetic mutation, of course, and genes that are extremely disadvatageous (i.e. allow little chance of survival) are quickly removed from our gene pool simply because people born with those genes can't be saved.

In the future, however, it will certainly be possible for couples to genetically "customise" their baby by choosing only the desired genes from the mother and father, or even create a "super human" by combining the best genes from a wide range of people.  It may even become commonplace to do so.  After all, while genetic tampering is frowned upon today, once the technique is perfected there will be literally no disadvantage in using this method to conceive a child.  The child could be more intelligent, more athletic and have superior senses and skills to anyone alive today.  If this were to happen, human evolution would take a giant step forward.  No undesirable gene need be kept in the gene pool - there would be no children born blind or disabled, no more cystic fibrosis, sickle cell anaemia, or any other genetic diseases. 

On the other hand, there would be many people whose religion or beliefs forbid the genetic enhancement of humans.  And, while the rest of the world evolved, this group of people would remain in evolutionary stasis.  In a sense, then, only a percentage of humanity will benefit from the evolution to come, while the rest will merely be observers.

[Skids]

I too shall don the moral bulletproof vest.
The Nazis were into genetic evolution. And for a while they were doing quite well at it. The only problem was the methods with which they chose to remove the 'undesirable' genes.

[stevie21]

As mentioned, the average height of people is constantly increasing so I think that this shows that we are still evolving.
Now, with technology to do all sorts of menial tasks for us, we'll evolve into huge noggins with no legs or arms.

OK, that last part was just a joke.

[magicdice]

we're still evolving, it can't just stop.

[newtron]

According to the theory of punctuated equilibrium, evolution is not necessarily a constant gradual process.  Once a species has found a niche in its environment where it could survive easily, there is really no need to evolve.  Generally big steps in evolution happen as a result of some sort of change in environment.  But as NetSqirrel pointed out, this big step in evolution may also be caused by the species consciously changing itself.

[jake-the-peg]

I suspect we may be evolving in ways we don't expect - tolerence to pollution for example.

There is a widely reported story (Don't know how true it is) that Westerners posess a gene absent in Easterners that makes them more tolerant to alcohol. Alcohol was widely drunk instead of water in the West because the water was not safe to drink.

Pretty difficult to second guess something like that

[MargeB]

"Evolve" does not mean 'get better' in any absolute sense, but in as much as a species is better adapted to a
niche. We live in a new niche, higher tec, but vastly more populated. You don't evolve to "survive" as
such, but to ensure the survival of your young (and to have some"). It's relative to some extent. If the bar is
pushed higher, it just means that either sex will go in search of better and better counterparts.

MOST importantly in this debate, is the 'gearing' of change. The gearing worked ok in the past, genetic
mutation was about right for the environment (it could select from a group that was changing fast
enough'. We still have a ton of traits hanging over from hunter gatherer times, with modern culture and
technology kind of slammed on this base. No wonder we keep getting ugly consequences. Given this, the
only way forward is where we accept this fact and work against it, not by ignoring it. None of us was
made for this age.

[MargeB]

We are more intelligent than all other apes, but this is not because evolution trends towards 'better' or
'cleverer'. For humans, it was probably just an accident (eg we became bipedal, so freed up our hands for
tools, so had to develop a bigger brain, or else could do more sign language, so had to develop a bigger
brain): rather than de Chardin's 'Spirit of Man' forcing animals to higher and higher things. Basically, we
changed from other apes, and simultaneously/consequently found a niche (hunter gatherer) that they did
not occupy. We could well not have evolved like this at all.
Despite all this, are we getting cleverer? I really think so. Once you produce great technology and the
demands to serve it, the sexual selection on higher intelligence becomes even greater. This is a kind of
'runaway' sexual selection, since clearly few women on earth nowadays really need a man to be around to
help out with the young to the extent that it really happened in our evolutionary past.
Excellent question.

[dimmy]

i think it's a bit harsh to call people with a religious belief nuts! it's no more a crazy than any other persons belief.

anyway that aside, dont you think you've made a fairly good point as to why we havent evolved? kind of shot yourself in the foot there.

[wyldkhatdd]

Hmm...reading ur responses I am wondering...If we have infact evolved, how so?

[magicdice]

wyldkhatdd we started off as a single cell, and all this kinda happened from there

[Kingaroo]

bob a job, what a great question! You are right, we have found technical work-arounds for many of the natural "predators" on humans. That means practically everybody gets a chance to reproduce and pass on their specific set of genes. That, combined with an insanely high birth rate in recent centuries (There are more people alive now than the total of everyone who has EVER lived!) means we have a huge, huge selection of genes in our species.

When the next big "selection pressure" hits (nuclear winter? melting the polar ice caps?), there will be a very diverse population with very rich genetic resources. Some kind of human descendents will live on to keep the cockroaches company.

For an interesting novel about the future of human evolution, read GALAPAGOS by Kurt Vonnegut. it sets the stage for the evolution of a nearly unrecognizable future human -- very plausible in a wacky vonnegutian way.

[Bob A Job]

dimmy - dont mean to offend and religous non-nuts, just inspire free thinking and a good old debate.

 

GOOD POINTS ALL OF YOU!!

food for thought - By the modern worlds reliance on money for survival, and jobs for money, and inteligence for high paid jobs. Are we evolving to be hyper inteligent and tech-friendly (take a look at 5 year olds on computers nowdays).

 

Yes we are taller and smarter, but id this evolution?

Arnt we just bigger and better because of better nutrition during adolesance?

Is our real evolution now just within our own gene pool and not against other species?

Thanks everyone.....

[MargeB]

I explained that...
If we are taller and smarter to fit and adapt to a niche....then it is evolution. Selection will be made FOR those who are more suitably adapted to ensure their gene survival.
RE a couple of other posts:
We don't pass on our specific genes (that's why evolution can occur: from some of our genes, and some of our partner, we pass on a mish mosh of genes). Besides, within the human species, you only need to go down a very small number of generations to find the specificity of your genes diluted....your partner may as well have had sex with anyone.
Human gene pool very diverse? Not at all. Humans have one of the tightest, least diverse gene pools of any animal. Population growth would not necessarily have led to a more diverse pool at all.
Mitochondrial DNA analysis of a wide population sample has revealed that at one point in the not to distant past, the human population must have cramped down to 20,000, which is tiny, and is presumed to account for our now extremely high genetic similarity.
It's easy for one to 'get' evolution, when in fact one's understanding is wayyyy of the mark. It's quite a complex business. Read 'The Selfish Gene' by Richard Dawkins, and you'll find out an awful lot!

[Flurfl]

Evolution is created by two things: people growing old enough to have children and people actually having them.

Anything that reduces the chances of this happening is selected against over enough time. On the other hand anything that increases the chances of this are selected for.

People getting taller has more to do with nutrition and more recently antibiotics. Even a cold or flu in childhood will actually stop your growth for a certain amount of time while your body fights it. I can't see any obvious selection pressure for tallness (people might fancy taller people but short people have children too, although do taller people have more children?).

An evolutionary process that is self evidentially occuring is that the world as a whole is becoming more dark-skinned. While western (read predominately white) countries birth rates are dropping  and becoming negative in many places. Many third world countries still have high birth rates, as we used to before medical treatment reduced the mortality rates of babies, children and young adults. While such treatment is now more widely (but not universally) available there is a certain "lag" period between less people dying and people having less children to compensate for the high death rate. As this occurs then the world's population will stabilise, by then there will be proportionally more  people in those countires than there are now. 

[Flurfl]

Another more dubious (and possibly unsupportable) evoultionary process in humans concerns your "religious nutters". Any community which has a celibate clergy would be at risk of breeding out religious belief, or at least it may become less fervent. If fervent religious belivers become priests or nuns and aren't able to have children then any genetic component and some nurture component to that strong religious belief is lost within that community.

Another possible example is puberty in girls. It has historically fallen in the western world since the 19th Century from around 17 to about 12 now. Again Nutrition and health care are most probably involved. But there may also be an evolutionary element. If you consider two things: one - that before this time children under the age of 16 could be married  and after this time it became increasing less possible (through laws and social mores)  and two - that early teenage pregnancies are dangerous for the mother and the baby. Then you can see that women who got preganant later (when the rest of their body had caught up to their womb) were selected for (ie they and their children wouldn't die in child birth) while those who got preganant earlier were selected against. Death rates due to these early pregancies  would have dropped as they married later and women that could of been had preganant in their teenage years were now delayed until they they married at an older age. So the fact that women in general can pregnant before the rest of their body is ready for it is no longer a selection factor.

Of course there exceptions to such things but when you talking about evolution you have to talk generalisations and percentages not particular cases.

[MargeB]

Well...you also got to stay old and fit enough to rear your young. This is because you walk.
Eh????????????????
you walk.......therefore restricted pelvis size......therefore restricted birth canal in female humans.....therefore restricted brain size in newborn.....therefore huge amount of time rearing young to adulthood (12 years). Meaning you gotta be around to support them.

Tall is great and is well worth selecting for. Humans beat the carp out of each other all the time and have to attack and survive attacks from large ugly dangerous animals, I'll take a tall un over a midget any day in that fight.

I love the religion argument but find it hard to find anything much written on this. One things for sure! Catholicism is an awesome adaptive strategy! Teach your kids and their kids that if they use methods to stop having kids (contraception) then they'll go to a bad burny place! Awwwesome. 9-children families here we come! Now THAT is spreading your genes.

[wyldkhatdd]

Um, yeah, thanks magicdice, but i meant recently...like in the past 500 years or so.

[delapeyre64]

I agree in part to the de-evolving side, as in nature the weak are weeded out really soon so don�t get a chance to procreate and further weaken the gene pool.
We are a product of nature and at our disposal is the inelegance to further our evolution faster than nature could ever do. We will also learn to colonise terra-form and adapt nature to suit us,
We are on the way to becoming the Gods of our ignorant past beliefs.