Is it possible for humans to evolve?

[alice]

Will we still evolve years from now?

[silkworm]

We're evolving right now, always. It never ends. But you probably mean speciation, and I personally don't think we'll speciate until populations of us are isolated during interstellar space travel.

[Genecks]

What is this recent crap on the boards with space travel???

Did someone bust out a new hypothesis, and did people start accepting it?

I understand the idea of allopatric speciation, but where is this space stuff coming from?

 

Did someone come up with an evolutionary theory based on space travel?

[alice]

silkworm, can you explain? I'm kind of low on the understanding part. What do you mean?

[Genecks]

He's probably talking about genetic populations.

 

When a population of people are distant from other populations, then both populations can't spread their genetic code around with each other.

 

With a population isolated in space, the alleles (genetic code/genes) in the population could change, mutate, or etc. over a period of time.

 

This would lead to an eventual change in the human genome and perhaps create a different species.

 

From what I'm reading on the board, however, it looks like people say gamma rays or some other space radiation can change the genome to create a new species within a population.

[alice]

Oh. Now I get it. Thanks!

[the tree]

What is this recent crap on the boards with space travel?

Did someone bust out a new hypothesis' date=' and did people start accepting it?

I understand the idea of allopatric speciation, but where is this space stuff coming from?[/quote']People have been popping up into space for ages, there's no reason why there shouldn't be permanent extra-teristrial settlements in the next three or four centuries.

Did someone come up with an evolutionary theory based on space travel?

No, just on travel. It's largely accepted that physical isolation can cause enough divergence for speciation. Not least because it happens all the time.

But as it's so insanely easy for humans to move around the planet, that's not going to happen for us until we spread over a much wider area and "regular" travel becomes impractical.

With a population isolated in space, the alleles (genetic code/genes) in the population could change, mutate, or etc. over a period of time.

Being isolated doesn't cause evolution, evolution is just a fact of life. The point is independant evolution as a result of isolation, that is what would cause speciation.

the alleles (genetic code/genes)

An allele is any one of a number of viable DNA codings of the same gene, not the gene itself.

From what I'm reading on the board, however, it looks like people say gamma rays or some other space radiation can change the genome to create a new species within a population.

No idea where you got that from. Gamma rays are measly little things that hardly ionise anything, even if they did cause genetic change, it wouldn't spur evolution unless it managed to hit a gamete and have a significant influence.

[Royston]

Alice, you should look up the 'founder effect,' with regards to population of another planet.

 

IIRC our brains have shown observable evolutionary change, I can't remember for better or worse, but change nonetheless.

 

EDIT: Actually I'm not sure the founder effect is applicable...sorry, been a few months since I studied evolution.

[bascule]

Transhumanists (including myself) are all convinced we're going to evolve into posthuman entities.

 

This goes through two stages really. The first is the cyborg stage: technologically augmented humanity. Most people associate the idea of cyborgs with replacing parts of your body with machine parts, or adding implants. But really that's not necessary at all. You can use an externalized brain-computer interface, one which scans the brain passively and can also alter brain state through entirely external processes.

 

The next stage (the one the identity problem is concerned with) involves mind transfer/downloading consciousness, in which you transform from a human entity into a purely informational form (but still manifested in some sort of material capacity, perhaps within some sort of distributed nanotechnological computing platform)

[alice]

Thanks for all the replies! When do you think that will happen-the next stage?

[the tree]

I'd argue that the first stage happened the first time someone manufactured a walking stick.

 

I can't imagine the second stage happening for quite some time.

[The Peon]

I've read many scientific papers stating we are actually still rapidly evolving to this day.

[CharonY]

Well, no big surprise. Changes in allele frequency will continue to occur unless there is some perfect environmental equilibrium as well as no further mutations, which could become fixed in the gene pool.

And this is extremely unlikely to happen, if one consider how rapidly especially in human societies the environmental factors are changing.

[RoyLennigan]

Thanks for all the replies! When do you think that will happen-the next stage?

its not an event that you can wait around to happen. its going to happen very gradually with short periods of intense environmental change that spurs selection for more rare traits. so it could be a few hundred years or it could be a few million years.

[CharonY]

A few hundred is probably too short. If we calculate with a generation of, say 30 years for humans, 300 years are only 10 generations.

Unless there are some catastrophes that result in significant, yet somehow specific elimination of a part of the human gene pool one would not expect significant changes.

[the tree]

If we calculate with a generation of, say 30 years for humans, 300 years are only 10 generations.

IIRC, it takes 5 generations to get from from something that definately is a wolf to something that definately isn't.

[silkworm]

He's probably talking about genetic populations.

 

When a population of people are distant from other populations' date=' then both populations can't spread their genetic code around with each other.

 

With a population isolated in space, the alleles (genetic code/genes) in the population could change, mutate, or etc. over a period of time.

 

This would lead to an eventual change in the human genome and perhaps create a different species.

 

From what I'm reading on the board, however, it looks like people say gamma rays or some other space radiation can change the genome to create a new species within a population.[/quote']

 

 

That's precisely what I'm saying. While we are humans are still evolving (different traits becoming more widespread) I think that Alice's question was more interested in speciation. Because the world is so small to us now and all human populations travel and interbread so readily the gene flow would make the speciation of any human group from the rest very very unlikely. I meant that when we reach a time of space travel populations will be isolated from each other and speciation may occur after a long time, time feasable in that case.

[silkworm]

Thanks for all the replies! When do you think that will happen-the next stage?

 

Absolutely not in our lifetime, but definitely at some point in the future barring any unforeseen massively devastating events that would effect our technology and strength as a species and if we can manage not to kill ourselves either purposely or accidentally.

[RoyLennigan]

A few hundred is probably too short. If we calculate with a generation of' date=' say 30 years for humans, 300 years are only 10 generations.

Unless there are some catastrophes that result in significant, yet somehow specific elimination of a part of the human gene pool one would not expect significant changes.[/quote']

of course. but even in one generation there is the possibility of a mutation that could make the offspring have a very different and new trait that the parents did not have. whether or not that mutation is beneficial is completely circumstantial (and usually it is benign or harmful). but with an environment change (such as isolation in deep space or a new planet or a post-armageddon earth) any minor advantages would be selected for very quickly. you can't put a time frame on how long it takes for speciation to occur because it could be as short as 2 or 3 generations or it could be longer than 1000 generations, or it could never happen. all it takes is one change in one organism that is better at survival and reproduction than the rest.

 

the problem with seeing any major change in human evolution is that we have adapted our environment to fit us, instead of the other way around. by making our environment a perfect habitat for ourselves, we no longer need to change to better fit our niche. cochroaches and sharks have remained relatively unchanged for millions of years because they fit their environment so well. we will continue to stay nearly the same as long as there is nothing to threaten our general existence. but there is still some selection--those that cannot survive wont; those that cannot reproduce won't add to the genepool.

[CharonY]

Just some points, in order for evolution to occur the allele frequency in a population has to change, right?

Let's assume there is one single mutation occurs. Does it change the gene pool? In theory yes. But on a population level it will not be observable. Now what still has to happen is that this new allele has to survive selective sweeps and spread. This takes a few generations. And this is only for a small variant to spread. Speciation takes much more radical changes in the gene pool composition (usually of isolated species). Two or three generations will never suffice for speciation. Even if highly isolated and specifically selected two random sub-populations are not likely to be too divergent to interbreed anymore.

 

To your second point, it is a common misconception that the human environment is a stable form that eliminates all elements of evolution. Some thoghts/examples:

- medications for certain genetic based diseases reduce the fitness reduction of bearers of these traits. Therefore these alleles might theoretically rise to a higher frequency than they were before

 

-availability of food can enhance the problems caused by alleles that promote obesity. Earlier theses alleles did not harm or might even have been beneficial as food availability was lower. The result is now a reduced fitness of bearers of these alleles

 

-in modern societies certain abilites are now more important than before, e.g. high body strength might not provide the fitness advantage it did before (except maybe in terms of sexual selection in some cases). Every change in fitness should result in allele frequency changes. And that again is evolution.

[alice]

So you're all saying that we will evolve if our environment changes...a very big change at that. But how do we evolve? Will we grow fur if our environment suddenly becomes colder (IceAge)? Grow fur, grow gills...something like that...mutate?

[the tree]

So you're all saying that we will evolve if our environment changes.

We'll evolve whatever, but significant evolution would require a significant change in our situation.

(I'd be wary of just saying a change in the enviroment, there a plenty other factors: if brains become so much more attractive than brawn, then the naturally muscley wont have such an advantage.)

 

But how do we evolve?

Some members of a generation will breed more than others, there traits will persist.

 

Will we grow fur if our environment suddenly becomes colder (IceAge)?

If it became so cold that our assistive technology can't deal with it then those who can keep themselves warm naturally will have an advantage, but that would have to be really cold.

 

Grow fur, grow gills...something like that...

Obviously we'd have to be aquarius before having gills, some really obscure natural disaster may help that happen but it's more likely that we'd go extinct first.

 

mutate?

Mutations are what makes evolution happen, yes.

[JaKiri]

But how do we evolve? Will we grow fur if our environment suddenly becomes colder (IceAge)? Grow fur, grow gills...something like that...mutate?

 

Mutation is the name of the game. (Things in brackets are examples, and not necessarily the sole examples)

 

Mutations are not directed, they are random. They involve the change of a small part of the genetic code, either by external action (the action of radiation) or by a simple copying error. Both of these are happening fairly regularly in everyone, but most of the time they don't get expressed; the gene isn't a relevent one (part of junk DNA), or it is "caught" by one of the myriad of backup systems the body has in place. However, quite often they slip through.

 

And, by and large, do very little.

 

However, they can cause problems; changes can be either big or small, depending on precisely what bit of the genetic code changes. A very simple mutation in the fruit fly drosophila (in the HOX genes, to be precise) can cause legs to grow where its eyes should be. However, the really really bad ones are generally weeded out - they are "deleterious" - because if they have bad adaptations, they're less likely to breed and pass on this trait to a new generation.

 

However, if they're good (or merely "mediocre" - this can include "bad" changes - autism is a possible example, because nowadays being autistic is not as unlikely to cause one to not pass on genes as it was in days gone by, whilst still arguably having a negative affect on the person with the condition) they may well be passed on, and, if sufficient people get the genes, or if there is a big advantage to having them, then they will get fixed in the population. However, genes which have no large "positive" to them can also be lost, by a process called genetic drift, which it isn't necessary to go into.

 

So what we have is a system of random mutations which can, possibly, make the thing carrying them more or less likely to breed. If they're more likely to breed, due to breeding faster, being better suited to gather food or whatever, then the population may well change.

 

This is natural selection.

 

It's all about passing genes onto your offspring, and evolution is the change in these genes over time, from one generation to hundreds.

 

One thing you will note, however, is that the changes are fairly small. The example with the fruit fly above is a strange case, because such an important part of development was controlled by a single, small, set of genes.

 

Most changes, like, say, developing functional gills, would require so much alteration of the genetic code that for it to happen through sheer random chance (which is how the mutations arrive; whether they stay in society is, partially, not random, but what mutations arise in the first place is entirely random) is so unlikely to be nearly impossible.

 

Good examples of human evolution is the gradual change in brain size over the last thousand to hundred thousand years, or the tendency in North East England of mining families, who had to work in cramped environments underground, to produce smaller children even with a similar diet to their taller classmates.

 

Evolving to a catastrophe is rare, extremely rare, and generally requires the ability to survive the castrophe to have existed in the population beforehand; a good example is bacteria attacked by antibiotics. There's a chance that some of the bacteria will already, randomly, be resistant to the antibiotic in question and so they will survive and the others will die, and so in the next generation nearly all of the bacteria will be resistant to the antibiotic. This is part of the reason why "superbugs" evolve; the other is that when you don't finish your treatment of antibiotics, there's a chance that some of the bacteria, who aren't resistant to the antibiotic, will have survived; they breed fast, and, in an environment when there's still antibiotics hanging around, there will be a big advantage to the bacteria who happens to randomly acquire a resistance to the antibiotic - so if that mutation appears, it will fast become fixed in the population, and you have the infection back, but this time resistant to whatever you used on it before.

 

This doesn't always happen of course; sometimes the bacteria just die out without having randomly mutated a resistance to the antibiotic. Think of this kind of extinction event to be similar to a board game. You land on a space that says "throw a 6 to continue", except in this case you have a hundred dice, and have to roll a 6 on all of them.

[Cloud]

To have a noticable change it would take a very long time, I'm talking tens of thousands of years, right? The allele would have to be passed down many generations for it to be considered a collective evolution. (e.g. were're not that different from the romans)

 

The people in Africa who are immune to malaria, can that be classed as evolution? It was passed down from generation to generation over a very long time.

[JaKiri]

To have a noticable change it would take a very long time, I'm talking tens of thousands of years, right?

 

Not necessarily. It could be hundreds, or less. It could be a week, if we're talking about a situation where most things die out suddenly.

 

The people in Africa who are immune to malaria, can that be classed as evolution? It was passed down from generation to generation over a very long time.

 

Yes, although the reasoning behind it is a bit overzealous.