Humans not evolving any more?

[Abaddon]

another problem is that seen as we breed so little;once or twice a lifetime, compare to animals which is usually every season. We will not see more successful humans breeding more as we dont choose to anyway.

-as for babys born in space- yes they would be deformed by earth standards.. but if they could have kids, if taken back to earth, they would be normal again.

 

[stormbind]

The adaptations that astronauts undergo while living in space are not transmittable to their offspring

Not directly, but those astronauts who cope better in space might breed more readily in that environment - and thus the genes which empowered some astronauts to cope better would be present in future generations of spacemen. I think that is where Bozo was coming from.

However, I still think astronauts would endeavour to create an Earth-like environment

 

[stormbind]

On the issue of family size, I think one of my wealthier recent ancestors had something like twenty children!

They don't make families like that anymore.

 

[Bozo Erectus]

You're mistaken. The adaptations that astronauts undergo while living in space are not transmittable to their offspring; that is simply not how evolution works. What you're suggesting is akin to those of nineteenth century biologists who hypothesized that, for example, giraffes came to have long necks since their ancestors constantly had to stretch to reach higher trees. What likely happened is that the giraffes with shorter necks were at a disadvantage in finding enough food, and bred less (since they died more often) than their taller-necked relatives.

The exact same mechanism is the only way that humans could adapt (in the genetic sense) to living in space. Those who have a slight advantage in coping with a zero gravity environment would die less frequently, and thus breed more often. Note that I'm not suggesting that this will happen, only that this is the only way it could happen (barring genetic modifications). Your idea that their children would be endowed with better traits to cope with the environment simply because their parents were placed in a harsh environment is plainly and simply wrong.

Ronald, no you misunderstood what Im saying. I dont believe that it would immediately be passed on genetically. This is what Im saying: people who spend extended periods in space experience physiological change. Astronauts begin losing muscle and bone density right away. Their cardiovascular system changes. When they return to Earth, they need to readapt to Earth gravity. These are facts, not opinion or speculation. So if these changes happen to an Earth human who spends just a few months in space, the effects of weightlessness on a human who was concieved, born and raised in space in zero gee would be even more profound. That zero gee human, even though he's the first generation born and raised in zero gee, would never be able to come to Earth. This is all basic stuff and its well known and understood, do a little google research on it, you'll see what Im talking about.

 

[stormbind]

Bozo, that is not genetic evolution - DNA is unchanged, even in the children cited. It is more a demonstration for how poorly evolved we are for life in zero-gravity. What might be possible is that only some children would survive, and then their genetic strengths might be influential.

 

[Bozo Erectus]

Its weird people are having difficulty understanding this Let me put it this way Storm: If from the day you born, you were strapped into a wheelchair, and never allowed to walk, and then one day when youre 20, somebody came along, freed you from the chair and stood you up, your legs would snap in two like matchsticks. You would never be able to walk. Anyone born and raised in space would be in the same exact situation, except it wouldnt be limited to just their legs, it would be their entire bodies which wouldnt be able to handle gravity. People born and raised in zero gee would have to remain in zero gee. How long before these physical changes became part of their DNA? I dont know, but it wouldnt take millions of years, especially not with genetic engineering around.

 

[cgannon64]

Bozo, I don't think the traits would be passed on genetically. I cannot see any trait arising that makes one more adapted to space and more likely to reproduce, especially since few people would be dying because they are 'less adapted'.

Nevertheless, it would be interesting because the humans who were born and raised in space, or in any other low-gravity enviroment, would never really be able to visit any high-gravity enviroment. Arthur C. Clarke talked about this once, I think. Humans wouldn't evolve into seperate species, per se, but we would split off into groups, some of whom would be incapable of visiting other groups in their native enviroment.

A fascinating scenario, but I don't think one that really involves evolution.

My opinion regarding this whole debate is that evolution lost, and humanity won.

 

[Bozo Erectus]

You're mistaken. The adaptations that astronauts undergo while living in space are not transmittable to their offspring; that is simply not how evolution works.

Bozo, that is not genetic evolution - DNA is unchanged, even in the children cited.

A fascinating scenario, but I don't think one that really involves evolution.

Guys, this is EXACTLY what evolution is How do you think speciation happens in the first place? You isolate breeding populations. Everybody forget about the Galapagos Islands, Darwin? One population on Earth, one in space, one on Mars, one on the Moon. Each world would be like an island in the Galapagos.

 

[a space oddity]

I believe evolution goes in leaps and jumps, and mostly so when big events occur. Humans will evolve when a major disaster will kill all those not 'fit' for the situation that exists after, we are less aloof of nature than we think.

 

[Abaddon]

yes, we have the seperation of genepools. But what evolution would need to occur before the different pools could not interbreed. Only then has speciation occured.

However the environment effects you has no effect on your genes. Yes there could be beneficial mutations occuring in space, but you cant imagine how many generations and the size of population this would require.

Also, genetic engineering- unless the gene exhists already, theres nothing we can do we cannot "make" a gene, merely extract it form one organism and add it to another. An i doubt there are many genes in nature that would be useful for us to use.

 

[Bluemofia]

The Human race is still evolving, as people on average are 3 inches taller than they were in the 1700s. Height is being favored.

@Bozo: But if the Z-G people were to reproduce, their decendants will be fine, as the actual DNA will be like a normal 1-G persons. Only if they have the underdeveloped limb muscle DNA they would evolve, as they will spend less energy at developing muscles that they don't need.

 

[cgannon64]

Guys, this is EXACTLY what evolution is How do you think speciation happens in the first place? You isolate breeding populations. Everybody forget about the Galapagos Islands, Darwin? One population on Earth, one in space, one on Mars, one on the Moon. Each world would be like an island in the Galapagos.

Yes, evolution happens through isolated populations - but it also happens because of genetic factors that increase the chance of breeding.

I am saying that, in modern society, we have pretty much eliminated our reliance on genes with regard to breeding. A number of diseases that would have been bred out of the gene pool remain because we have such a low death rate.

You could seperate our populations as much as you want, but unless one of them loses modern medical technology, I don't see how they will evolve.

 

[cgannon64]

The Human race is still evolving, as people on average are 3 inches taller than they were in the 1700s. Height is being favored.

Actually I've heard this is because we have a better awareness of nutrients and better diets than people in the 18th century and earlier.

 

[Abaddon]

and all the growth hormones in meat

 

[Babbler]

Homo sapiens will continue to evolve. Biological evolution just means that change in the frequency the genes of species. I am sure that the gene pools of humanity will change; maybe natural selection will stop being an important factor and genetic drift, sexual selection and artificial selection will become more important.

 

[SonicX]

Ofcourse humans are still evolving and due to changed habits, evolution is going faster than ever before I believe.
We've grown like 10 to 20 centimeters on average the last 2 centuries due to better food, but that will ofcourse impact our genes who need to cope with that extra height and body weight.
We need to think a lot more than we did before due to science, while we need our insticts less and less, and I can't help but believe that will make humans smarter and less impulsive in scientifical or educationally high societies.

There are two clear cases that prove the ongoing evolution of the human race.
1. After the plague in Europe, about 12 % of the Europeans have gained a gene called Delta-32, which makes the body invulnerable to the plague and also to HIV (a plague-like virus). This gene is only found in a fraction of the European populace and nowhere else around the world, which proves genetic evolution to cope with new threats.
2. Indians have had to cope with lots of famines in their history due to mousson droughts whenever and El Niño (or Niña, don't remember) occurs and constant overpopulation. Therefore Indians have had a genetic alternation which makes them store up to 33 % more fat from carbonhydrates than other races ... this is also the prime explanation why this billion-man country always scores bad at the Olympics, they're built for surviving famines and have too much body fat to be suitable for top sport (on average, ofcourse)

 

[Neonanocyborgasm]

With things such as the NHS and charity.. are humans still experiencing any evolution, or has it slowed down to negligable levels. Selection pressure, which is the driving force in evolution is devoid in our lives.


...and why we arnt telepaths yet

We are no longer subject to the same selection pressures as wild animals are. We have medical care, protection from the elements through housing, and charity. So, yes, in that sense, we are no longer subject to "natural" selection. However, there may be some "artificial" selectors, like selection by intelligence, beauty, or commercial acumen that, depending on the society, may earn reproductive advantage.

 

[stormbind]

If from the day you born, you were strapped into a wheelchair, and never allowed to walk, and then one day when youre 20, somebody came along, freed you from the chair and stood you up, your legs would snap in two like matchsticks. You would never be able to walk.

The DNA would be unchanged. My offspring would carry the same genetic code regardless of what life had been led. Cell reproduction, and evolution would be unaffected.

The problem is not your perception of what zero-gravity does to the body. The problem is how you perceive it affecting DNA, RNA and cell reproduction.

 

[Ultima Dragoon]

We are no longer subject to the same selection pressures as wild animals are. We have medical care, protection from the elements through housing, and charity. So, yes, in that sense, we are no longer subject to "natural" selection. However, there may be some "artificial" selectors, like selection by intelligence, beauty, or commercial acumen that, depending on the society, may earn reproductive advantage.

What about people who choose to "rough it" or athletes? A family of athletes are under constant pressure to have the most advantagious traits for an athlete? They, after a few genarations will possibly have:

Larger lungs
Stronger hearts
denser bones
stronger muscles

than people who are not under the constant pressure of performing as an athlete.

 

[Bozo Erectus]

The DNA would be unchanged. My offspring would carry the same genetic code regardless of what life had been led. Cell reproduction, and evolution would be unaffected.

The problem is not your perception of what zero-gravity does to the body. The problem is how you perceive it affecting DNA, RNA and cell reproduction.

The problem is that you fail to understand that the effects of gravity would create seperate breeding populations, which would lead to speciation.