Time of evolutionary change

Vangelis

How many generations does it take for a population( in which individuals breed with one other individuals of the same population), to develop characteristic genetic traits and specific phenotypes?

samb

It is a strangely put question, one that leads me to think you may not understand evolution properly...athough I might be wrong, its made me a little confused. Is the answer as simple as I think or are you asking a differnet question.

I think this is the answer.
It takes zero generations. When a genetic mutation takes place within an individual this will be evident (result in ''characteristic genetic traits and specific phenotypes'') once that individual organism develops to the point at which that gene is utilised resulting in a phenotype different from the rest of the population.

If you are asking how many generations it will take before this gene becomes widespread within the population, then this will depend on many variables

Some include;
what your defintion of widespread is, >50% maybe
How beneficial the particular gene is in terms of reproduction. (may be only slightly beneficial in which case its spread would be slower)
Are the geographical impedements to population movement. (island population, dispursed population etc)
Other environmental factors that may be variable from year to year. (food availablity, predation, weather,)
Is the particular organism male or female (generally a very sucessful male can be more sucessful than a very succesful female).

Each one of these and many others that I can't think of right now would make an interesting discussion.

OY

I have been thinking about this since last weekend when i was bored and watching a rerun of Waterworld! For those of you who have not seen it.. mankind has been reduced to living in sparse floating cities and on boats and Kevin Costner has developed gills to help deal with this setback and which come in handy in a world filled with water!

So obviously this is an example of evolution taking place. But i cannot understand why it would happen and how it would happen! Is evolution associated with thought? If as a parent i look around, see more water, think it would be great to be able to swim underwater, do my children suddenly have a chance to possess gills? How does the foetus know what it needs to develop in order to survive?

My understanding of evolution have been that it is almost a fluke in each case. For example, a herd of horse like creatures live on the plains. A freak is born with a longer neck than normal but finds itself in an advantageous position as it can feed off food higher in the trees. Thus it is stronger and more attractive as a mate and its genes are passed on. Then over time the 'long neck' gene gets propogated and this freak becomes a new species. (It is a giraffe btw )

In hundreds of years man has not really evolved as far as i can see, no extra arms or ears! So why would Kevin Costner suddenly develop gills just because they are helpful?

I guess my ultimate question is how do the cells know what to develop? Are there some connection between the parents thoughts and life struggles that are passed on to the sperm or egg? There are so many species on this planet that have developed attributes related specifically to their environment but how did they know to develop those attributes?

I am by far no expert in this field and to someone who has studied this my thoughts may appear to be the rants of an idiot but i honestly have been thinking about this 'instant evolution' and how it could happen? Any insight would be appreciated...

- OY

DrIndy

Significant evolutionary leaps occur at pressure points when there is a sudden change in conditions which results in pressure on the survival capacity of the organism to continue. As a result of this, small changes mean advantages, they do not neccesarily become more attractive as a mate, but in fact can be the only group that actually survive to mate!

In humans a good example is sickle cell anaemia. Malaria is widespread in africa and kills many people at a young age. If you have 1 sickle cell anaemia gene and a normal one, you have higher resistance to malaria and hence survive to propagate.

[there are a couple evolution threads here so they have been merged]

Vangelis

OY, I think that for your children to develop gills, you would need to carry genetic codes for gills yourself. Maybe you would be one lucky human who had gills.

It happens so that nature selects the genetic traits that are most preferable in a given environment. I've heard that they use giraffes as an example. They needed longer necks in order to eat from the trees that grew taller. Some giraffes had long necks and that resulted in these giraffes mating. The ones with short necks died after a couple of generations because they weren't as viable as the long-necks. This natural selection happened when giraffes chose to mate with long-necked giraffes as they were more viable. Or so the theory says.

So it could be that we don't have any extra arms or eyes or whatever *chuckle* because *chuckle some more* we don't need it. For that to happen, someone would need to have extra arms and other limbs that were preferable in a specific environment. And they would have to multiply with people who preferred multi-armed individuals.

*Starts humming Right Said Fred's "I'm too sexy.." *:D

DrIndy, having one sickle cell anaemia gene, isn't that.. unhealthy?

samb, I meant.. how long does it take before a populations genes to evolve so that you can distinguish one species from the other? Hope that makes it clearer.

the_syco

OY wrote:

In hundreds of years man has not really evolved as far as i can see, no extra arms or ears!

IMO, the kicker is that they'd be seen as freaks, and thrown into the freak show. An ape may see an extra hand as usefull, and they may breed to a new species, but humans would try to isolate, or kill, anyone that looks different from the "norm".

DrIndy

One sickle cell gene confers resistance to malaria, but it does very little else to host. Likewise one cystic fibrosis gene confers resistance to cholera. People with cystic fibrosis are actually immune to cholera completely.

Here you have selection of a genetic trait which causes harm. If you moved people with the sickle cell trait to europe, it would gradually die out as there is no survival advantage and one in 2 children of those affected families would be unable to reproduce as they would be too sick.

Vangelis

That's interesting. *pensive*

Capt'n Midnight

If there is no competitive advantage in one form of a gene over another and both are half the population then you'd think both varieties would stay stable at 50:50 over time .

Mathematical modeling shows that eventually one may dominate and the other be lost by random chance over thousands of generations. If you toss 100,000 coins at once, the chances of getting exactly 50,000 heads is fairly small. This means that after a few unlucky generations one form may reduce far enough below 50% that the other form becomes dominant. Of course since there is no selective pressure a gene could go from one new mutation to most of the population, just the luck of the dice.

Also if the population is reduced at any time ( like humans were around the time of "eve" ) the chances of the rarer form of the gene (rarer at that time) disappearing are higher.

Evolution has changed for us because fewer of us in the west are dying of genetic before we can reproduce. Interestingly enough up to 20% of homosexual men have been married at some stage (* no I can't remember where I saw that statistic ) so would they reproduce less ? Single parent families are on the increase ( most births in Limerick at the moment ) - does this just represent a lack of weddings or more gene mixing than previously ?

As for time to change populations - look at the "races" that came out of Africa and how recently they left, remember there was an Ice age not that far back and how long was it since man first crossed the Bering Strait ?

samb

samb, I meant.. how long does it take before a populations genes to evolve so that you can distinguish one species from the other? Hope that makes it clearer

It's still not very clear. Are you talking about speciation (two species evolving from a common ancestor) or are you talking about one species evolving to the extent that it would not be classed as the same species it was before (i.e it would not be able to reproduce with its ancestor if brought back in time).

I recommend you study tortega's post. All of the variable factors I mentioned in my prevous post are relevant either way.
either way, the amount of time and generations it will take is variable due to its dependance on those variables.

GuanYin

Vangelis wrote:

How many generations does it take for a population( in which individuals breed with one other individuals of the same population), to develop characteristic genetic traits and specific phenotypes?

There is no set answer.

It depends on things like selection pressure.

Theoretically it could happen in one generation if say, a specific disease were to occur that proved fatal to a certain genetic or even phenotypic disposition - only those with a resistant genotype or phenotype would survive to breed.

Capt'n Midnight

samb wrote:

samb, I meant.. how long does it take before a populations genes to evolve so that you can distinguish one species from the other? Hope that makes it clearer

Ah the old "what constitutes a species" question ?

There is a type of gull that is found around the North Atlantic coast. There is a graduation of characteristics across the range. Birds will mate with others nearby , but birds from the two extremes will not mate with each other. They swapped the eggs and the chicks learnt the mating cries and preferences of their parents / siblings but the locals saw these intruders as being visually different and didn't mate with them. Are they the same species, well if you pick populations closer together then yes, without a doubt.

But it raised the problem of A and B are the same species AND B and C are the same species but A and C may not be !

As for time scales - look up the cichlids in Lake Tanganyika. Or the freshwater mussels in Hungry? between the Ice ages for events where species diversity exploded in to new environments in a short (few thousand years) time.

Vangelis

the_syco wrote:

IMO, the kicker is that they'd be seen as freaks, and thrown into the freak show. An ape may see an extra hand as usefull, and they may breed to a new species, but humans would try to isolate, or kill, anyone that looks different from the "norm".

Humans don't kill or isolate(at least not like animals: we may mock and tease, but that's typically teens?) those who are different from the norm.

We actually take care of those who are weaker or not so viable as other people. Which is puzzling. To help evolution continue its course, we should be eradicating people who do not have the 'preferred' genetic traits, if though there are many different preferences. Or at least depriving them of good living conditions provided by health care, medications, recreation facilities etc. But we don't. We take care of the 'weaker' ones.

Why do we do this?

Vangelis

No I think a better way to look at this is, an individual is more successful - feeds more often, is stronger, better prepared to escape predators and survive illness or harsh conditions and therefore MORE LIKELY to be LUCKY enough to find a mate, reproduce and pass on its genes.

Does this function among humans? I wonder. I see people who are not 'supposed' to be attractive as mates, unintelligent people, people who are not as capable, perhaps viable and potent as others, who marry and have lots of children.

They pass on their bad genes! We can't allow that!!

John

Vangelis wrote:

Humans don't kill or isolate(at least not like animals: we may mock and tease, but that's typically teens?) those who are different from the norm.

Check out Germany around the 1930s and early 40s for not killing those who deviate from the norm.

And we do isolate those that are different from the norm. The mentally ill are put into institutions, criminals are put into prison, homeless are ignored, bullying of people over how they look, etc. Yes people fall in love with the seemingly ugly but beauty isn't the only component of sexual selection. Character, status, wealth, health and many other smaller factors contribute to sexual selection.

Vangelis

John2 wrote:

Check out Germany around the 1930s and early 40s for not killing those who deviate from the norm.

And we do isolate those that are different from the norm. The mentally ill are put into institutions, criminals are put into prison, homeless are ignored, bullying of people over how they look, etc. Yes people fall in love with the seemingly ugly but beauty isn't the only component of sexual selection. Character, status, wealth, health and many other smaller factors contribute to sexual selection.

But there was nothing unnormal about Jews, homosexuals and gypsies(last one I'm insecure of). The norm we speak of here was not a biological norm, it was an illustion created by socialdarwinism that Jews are not human, that gypsies are not intelligent and so on.(Might have been from lack of education, but they can change that!)

Yes, mentally ill and people ill for all reasons are isolated, but not let alone to die, as among animals. Some of the have children, criminals too. Homeless are not, in my opinion, homeless for biological reasons. Do they lack genetic traits that could make them attractive as wives and husbands? I don't think so. They've just been unfortunate.

What about those who care for criminals, mentally ill and homeless?

Do they have 'unwanted' genes too because they show kindness?

John

Vangelis wrote:

But there was nothing unnormal about Jews, homosexuals and gypsies(last one I'm insecure of). The norm we speak of here was not a biological norm, it was an illustion created by socialdarwinism that Jews are not human, that gypsies are not intelligent and so on.(Might have been from lack of education, but they can change that!)

They deviated from the perceived norm of those in charge. And it wasn't just ethnic/gender minorities that were persacuted under the Nazis, the mentally and physically disabled were sterilised and executed. My point is that humans do isolate those that they think are a threat or not worthy of being part of their society, the Holocaust is an extreme example. The sociological side of it is social darwinism but I do think that humans are capable of it because they naturally have those tendencies.

Yes, mentally ill and people ill for all reasons are isolated, but not let alone to die, as among animals. Some of the have children, criminals too. Homeless are not, in my opinion, homeless for biological reasons. Do they lack genetic traits that could make them attractive as wives and husbands? I don't think so. They've just been unfortunate.

They are not left alone today in all cases but there have been many scandals involving despicable conditions in mental hospitals and orphanages in so called developed countries. It's not how well they are looked after in these institutions but the fact that they are put in them in the first place, society has deemed them unnacceptable and they are kept out of the way so "normal" life can continue uninterrupted.

I'm not saying homeless people are homeless for biological reasons (even though some are, mental illness and addiction are incredibly high in homeless people). I am saying that they exhibit traits and behaviours that make society not want to pay attention to them. How many times have you looked at a homeless man and thought "He's quite sexy"? They could well be handsome and intelligent but you've in built prejudices against those that could be dangerous, diseased or just plain unsuitable for a partner.

What about those who care for criminals, mentally ill and homeless?

Do they have 'unwanted' genes too because they show kindness?

No, of course not. I'm not saying everyone in the world is hard hearted and only interested in who they can bed. Life isn't that simple. People do care because they are very social animals. I'm just saying that people also have in built prejudices against things they perceive as threatening. Some people can overcome these prejudices and others can't.

samb

Vangelis wrote:

Do they have 'unwanted' genes too because they show kindness?

I think you are a very limited understanding of evolution. All human characteristics have evolved because they were beneficial. Hate, Rape, Callouss murder, anger, jealousy, greed, fear of ''otherness'' can all be beneficial behaviours for reproduction and this is why they exist and are part of human nature.

Equally however; Love, kindness, paternal and maternal love, sympathy, empathy, the ability to cooperate in groups etc are beneficial behaviours for the propogation of ones genes. Evolution has created the good and the bad of human nature.

What we must try to do is set up a social democratic democracy that tries to lead people away from the bad attributes and towards the good. If people recieve; love, kindness, empathy, esteem, they tend not to feel the need to carry out the bad behaviours mentioned above. It is naive and counter-productive to label any behaviour as evil, when all these behaviours are natural.

when you asked, why do we look after the weaker ones, I thought you at first you were suggesting we do not. hopefully we have evolved brains big enough to largely leave our evolutionary heritage in the past (of course our genes will flow through the population).

Vangelis

John2 wrote:

They deviated from the perceived norm of those in charge. And it wasn't just ethnic/gender minorities that were persacuted under the Nazis, the mentally and physically disabled were sterilised and executed. My point is that humans do isolate those that they think are a threat or not worthy of being part of their society, the Holocaust is an extreme example. The sociological side of it is social darwinism but I do think that humans are capable of it because they naturally have those tendencies.

I have met quite a few who don't have those tendencies. Are they better evolved? I've met myself too. I think it's unfair to label all humans like this.

They are not left alone today in all cases but there have been many scandals involving despicable conditions in mental hospitals and orphanages in so called developed countries. It's not how well they are looked after in these institutions but the fact that they are put in them in the first place, society has deemed them unnacceptable and they are kept out of the way so "normal" life can continue uninterrupted.

So it has. But where would the orphans go if there was not an institution? Weeren't these institutions designed to take car of them? Some are adopted I've heard. But if they are so unwanted we might as well execute them. They're not worth a prick.

But of course they are! They can teach us a lot and if the children get the chance, they can become something. Make a living. And we're developing medicines and treatment methods for the mentals. Now why do that? I think it is because we care.

I'm not saying homeless people are homeless for biological reasons (even though some are, mental illness and addiction are incredibly high in homeless people). I am saying that they exhibit traits and behaviours that make society not want to pay attention to them. How many times have you looked at a homeless man and thought "He's quite sexy"? They could well be handsome and intelligent but you've in built prejudices against those that could be dangerous, diseased or just plain unsuitable for a partner.

If the homeless looked a bit different they could be sexy. In the animal world, partners are either attractive or unattractive and will mostly stay that way. People can change if they are given the chance and many wealthy people work to make this happen.

I don't have prejudices against those who have "small equipment". In fact I have decided to dedicate my future job to those who need it the most.

No, of course not. I'm not saying everyone in the world is hard hearted and only interested in who they can bed. Life isn't that simple. People do care because they are very social animals. I'm just saying that people also have in built prejudices against things they perceive as threatening. Some people can overcome these prejudices and others can't.

Good! I think there are very few people who cannot actually overcome their prejudices.

Vangelis

samb wrote:

I think you are a very limited understanding of evolution. All human characteristics have evolved because they were beneficial. Hate, Rape, Callouss murder, anger, jealousy, greed, fear of ''otherness'' can all be beneficial behaviours for reproduction and this is why they exist and are part of human nature.

I have a good understanding of evolution. I'm just questioning things.
And those are your words. I see no logic in them.

Equally however; Love, kindness, paternal and maternal love, sympathy, empathy, the ability to cooperate in groups etc are beneficial behaviours for the propogation of ones genes. Evolution has created the good and the bad of human nature.

How nice.

What we must try to do is set up a social democratic democracy that tries to lead people away from the bad attributes and towards the good. If people recieve; love, kindness, empathy, esteem, they tend not to feel the need to carry out the bad behaviours mentioned above. It is naive and counter-productive to label any behaviour as evil, when all these behaviours are natural.

I disagree. Democracy has allowed for all personality types to influence society. Some of them are greedy, some selfish, some hating. Democracy as I experience it, is not based on love, it's based on a detached sense of fairness.

when you asked, why do we look after the weaker ones, I thought you at first you were suggesting we do not. hopefully we have evolved brains big enough to largely leave our evolutionary heritage in the past (of course our genes will flow through the population).

We do look after the 'weak' ones. I don't see any context between the two sentences here.

homah_7ft

I think this thread went awry somewhere along the line. There seems to be some misconception of what evolution is, as well as the mechanism behind it. The latter posts seem to confuse evolution with progress. There is no hand directing natural selection. It is purely an occurance of genes producing an effect which makes them more likely to enable the holder of the genes (animal, plant etc) to reproduce and pass on the genes.

They do not have to be more desireable to the opposite sex. For instance in the case of animals. Say hypothetically there was a male gene that caused the production more viable sperm cells. The male in question would not need to mate more frequently therefore there would be no need to be more desireable to the opposite sex.

Also to mention the comment on how evolution has caused behaviours like violence. There is a danger of falling into determinisim here. But just to comment that my hypothetical gene that causes more viable sperm to be produced by the animal could have other consequenes for the animal. Giving an extreme example it could cause red eyes. The red eyes themselves are not an advantage over non-red eyed animals but are a side product.

Finally evolution is not a league table. We do not stand at the top as the perfection of millions of years of evolution. There is no end to evolution it's an ongoing process. Also no genotype/phenotype could be called better than another.

samb

Vangelis wrote:

And those are your words. I see no logic in them.

Explain?

All human behavours are natural, that does not mean that they are desirable. Athough democracy is not perfect, we need some system to try to incourage and restrict undesirable human behavours. It may well seem like a detached sense of fairness.

homah; I have not fallen into any of the falacies you mention. I am not being deterministic, I think things like rape are natural that is why we must devise artificial institutions such as Courts, Police etc to counteract and discourage it. This is actually what we have done, with admittedly limited success. These undesirable behavours are not inevitable, but to reduce them we do need some kind of welfare state

John

Vangelis wrote:

I have met quite a few who don't have those tendencies. Are they better evolved? I've met myself too. I think it's unfair to label all humans like this.

There's no such thing as better evolved. I think you are confusing morality with evolution here somehow.

And we're developing medicines and treatment methods for the mentals. Now why do that? I think it is because we care.

I never said we couldn't care, I'm saying that people have a lot of built in knee-jerk reactions towards certain things. Most people are not vegetarians but I don't think anybody thinks killing an animal is right. In the same way no one thinks anyone should suffer or be homeless but how much do they give to charity or do for volunteer work? The majority of people do very little.

In the animal world, partners are either attractive or unattractive and will mostly stay that way.

Humanity is part of the animal world. There is as many complications and changes in status/attractiveness in the rest of the animal kingdom as there are in humans.

Homah, I agree that there is some confusion with evolution here. And I'm not being deterministic either, believe me if there's one thing I don't believe in it's that.

GuanYin

Vangelis, how many time are you going to bring the same general argument into a thread. Asking the same question 20 times in order to get the answer you want won't help matters.

Reading through your posts here you seem to have completely disregarded almost everything you seem to have learned or taken in from other threads.

Mostly regarding your perception of what evolution is, how it applies to humans, the mechanism by which it works and what it does and does not do.

Are you simply ignoring previous posts because they don't give you the answer you want or is there another reason you have disregarded 20-30 odd posts on other threads that explain in depth the general questions you ask here?

Vangelis

samb wrote:

I have not fallen into any of the falacies you mention. I am not being deterministic, I think things like rape are natural that is why we must devise artificial institutions such as Courts, Police etc to counteract and discourage it. This is actually what we have done, with admittedly limited success. These undesirable behavours are not inevitable, but to reduce them we do need some kind of welfare state

I think it's enough to reply to this.

Are courts, police etc natural behaviour too? They must be if rape is a natural behaviour. But who does rape benefit?

Vangelis

John2 wrote:

There's no such thing as better evolved. I think you are confusing morality with evolution here somehow.

I think so too, sorry.

I never said we couldn't care, I'm saying that people have a lot of built in knee-jerk reactions towards certain things. Most people are not vegetarians but I don't think anybody thinks killing an animal is right. In the same way no one thinks anyone should suffer or be homeless but how much do they give to charity or do for volunteer work? The majority of people do very little.

But these built in reactions, are they social or biological?
Hm, in my country people are very generous. Norway is the country that gives most money per person to any cause such as finding a cure for HIV/AIDS, poverty, cancer research, orphan care. The fact that some other countries may not do this seems to me rather to be a social thing than a biological thing. Norwegians are no more social-minded than other people.

Humanity is part of the animal world. There is as many complications and changes in status/attractiveness in the rest of the animal kingdom as there are in humans.

Yes, we are, I knew that we are part of the animal world.
Okay, that's fine.

Homah, I should word myself differently and say 'preferable' instead of 'better' about genotype/phenotype.

psi wrote:

Mostly regarding your perception of what evolution is, how it applies to humans, the mechanism by which it works and what it does and does not do.

I keep exploring. I don't look for the answers that I want to find, I'm just trying to learn about different ideas. And I'm tired of you criticising me and doubting my understanding of evolution. If you don't have anything useful to say, go away. I understand evolution, but I am exploring different ways of viewing it.

John

Vangelis wrote:

I think it's enough to reply to this.

Are courts, police etc natural behaviour too? They must be if rape is a natural behaviour. But who does rape benefit?

The rapist. He fathers a child without any of the responsibilities (provided the woman doesn't get an abortion). And yes, courts and police are natural behaviour because they exist at all. Just like any behaviour related to any one species is still natural, just idiosyncratic.

Vangelis

John2 wrote:

The rapist. He fathers a child without any of the responsibilities (provided the woman doesn't get an abortion). And yes, courts and police are natural behaviour because they exist at all. Just like any behaviour related to any one species is still natural, just idiosyncratic.

But many women take abortion after being raped. Then this must also be natural behaviour. Some may not have the chance to do it.

I think that many men who rape women do this also to express power over the women. They don't necessarily think that 'Now I can pass on my genes to the next generation'. So raping for the expression of superiority/power or to do harm, must be natural behaviour too in my opinion. Or else the men wouldn't think like this.

Or are these mindsets only cover-ups for the real intention of rape which supposedly is procreation?

homah_7ft

I think the use of the word natural is too loaded in this context. Especially since one of the meanings of the word implies the exclusion of human influence. I believe the introduction of rape/violence in the discussion is not relevent particularly to evolution. Why does it have anything to do with evolution? That could be said of anything that exists in human behaviour. Rape/violence does not have to have an evolutionary advantage just because it exists. I would refer back to my example of the red eyed animal.

samb

homah_7ft wrote:

I think the use of the word natural is too loaded in this context. Especially since one of the meanings of the word implies the exclusion of human influence. I believe the introduction of rape/violence in the discussion is not relevent particularly to evolution. Why does it have anything to do with evolution? That could be said of anything that exists in human behaviour. Rape/violence does not have to have an evolutionary advantage just because it exists. I would refer back to my example of the red eyed animal.

I'm not sure if this post was directed at me, but you are right. Some below seem to think that when I said Rape was natural I was somehow saying it was good, natural does not equal good or tolerable. And yes the word natural is a bit dodgy, is everything natural? Rape does not have to have an evolutonary advantage but I would think that violence probably does as well as the sex-drive. When these combine you get rape maybe.
I made the point about rape being natural because someone seemed to be suggesting that kindness was '' less evolved'' or something like that. I was just making the point that all behavours are evolved (good and bad) because they are beneficial, or as you have rightly pointed out as bi-products

GuanYin

Vangelis wrote:

I keep exploring. I don't look for the answers that I want to find, I'm just trying to learn about different ideas. And I'm tired of you criticising me and doubting my understanding of evolution. If you don't have anything useful to say, go away. I understand evolution, but I am exploring different ways of viewing it.

I'm not criticising you. I'm asking you questions.

You clearly don't understand evolution, you may think you do, but from your posts its abundently clear you don't. That isn't a criticism, its merely an observation.

Incidently, considering the quality and attitude of some of your posts (like the ones where you post 4-5 lines specifically to slag me off), youre a hypocrite to post something like this.

DrIndy

Folks, lets keep this a scientific debate. Concerns regarding morality and human society as it exists, (rather than the evolution of it such as the development of language) are more appropriate for Humanities.

Unpossible

I think it will be ok to put my question in this thread because I think its similar to what the original poster was asking;

How do/did "ethnic" changes come about?
For instance I would have thought that because all humans came from the same place (which Im told is africa), then shouldnt the only difference between me, my asian girlfriend & my african classmate be a different shade of skin (depending on the amount of sunshine in our countries), yet there are other clear differences. such as:
noses (it was pointed out to me that far eastern asians and africans have a differnt type of nose to westerners)

eye colour (if brown is the dominant colour then how did green, blue and grey come about)

hair colour ( again in school we were taught that dark hair is the dominant colour, so if all humans originally had dark hair how did we get the other colours?)

Skin colour (some of us just plain dont tan, no matter how long I spend in the sun I wont be as dark as my girlfriend, and she cant get as dark as my african friend, who in turn cant, I presume, become lighter if he avoids sunlight).

When humans migrated around the world did we mix with other species? are these differences a form of evolution?

My reasons for asking are not because Im racist, Im just really curious as to how these differences came about in humans, especially as it seems to me that darker genes are stronger/dominant.

John

Vangelis wrote:

But many women take abortion after being raped. Then this must also be natural behaviour. Some may not have the chance to do it.

I think that many men who rape women do this also to express power over the women. They don't necessarily think that 'Now I can pass on my genes to the next generation'. So raping for the expression of superiority/power or to do harm, must be natural behaviour too in my opinion. Or else the men wouldn't think like this.

Or are these mindsets only cover-ups for the real intention of rape which supposedly is procreation?

To take abortion may be a natural behaviour but before the last few decades to try and abort a baby was essentially suicide for the mother. I never said that men do think that they passing their genes on to, it is well established that it is a power thing but rape has been selected for because men who rape inevitably father children. Apart from the conscious decision to have a baby with a partner, no one thinks about their behviours in terms of passing on genes but if you subscribe to selfish gene theory, everything we do is somehow related to passing on our genes.

And please not I'm not saying that rape is a good thing because I think there is an evolutionary reason for it.

John

No, I am saying that people have a capacity for rape because of our evolution. There has never been a genetic link directly made to rape. However like any behaviour we can only be capable of it if our minds allow it. And our minds are subject to evolution. I'm slightly locked right now so forgive me if I'm not clear.

samb

Unpossible wrote:

I think it will be ok to put my question in this thread because I think its similar to what the original poster was asking;

How do/did "ethnic" changes come about?
For instance I would have thought that because all humans came from the same place (which Im told is africa), then shouldnt the only difference between me, my asian girlfriend & my african classmate be a different shade of skin (depending on the amount of sunshine in our countries), yet there are other clear differences. such as:
noses (it was pointed out to me that far eastern asians and africans have a differnt type of nose to westerners)

eye colour (if brown is the dominant colour then how did green, blue and grey come about)

hair colour ( again in school we were taught that dark hair is the dominant colour, so if all humans originally had dark hair how did we get the other colours?)

Skin colour (some of us just plain dont tan, no matter how long I spend in the sun I wont be as dark as my girlfriend, and she cant get as dark as my african friend, who in turn cant, I presume, become lighter if he avoids sunlight).

When humans migrated around the world did we mix with other species? are these differences a form of evolution?

My reasons for asking are not because Im racist, Im just really curious as to how these differences came about in humans, especially as it seems to me that darker genes are stronger/dominant.

Very good questions raised here that I certainly can't answer with certainty. We are all decended from a small group of africans that left Africa about 170 thousand years ago. In evolutionary terms this is a very short time, which is why we humans all have very similar DNA even though we are so widespread. Therefore all the changes you are talking about happened within this short period of time. I think white skin has the advantage of absorbing more vitamin D which would therefore be advantagous for people exposed to less sunlight. Dark skin is of course good protection against skin cancer. Some have suggested that racism could have played a significant role, the theory goes that once a reasonable difference in skin colour developed the two groups were racist towards eachother leading to that difference continuing. A kind of sexual selection could also have contributed, with people selecting a partner based on thier skin colour. Whiter or Blacker could have been fashionable.

Other differences such as difference between East and West africans could be due to differing lifestyle and environmental pressures. Geographical isolation is also likely to be a very important factor.

So to answer your question, it is complicated. Someone else please go further, John 2, tortega, psi, homah........

Vangelis

John2 wrote:

To take abortion may be a natural behaviour but before the last few decades to try and abort a baby was essentially suicide for the mother. I never said that men do think that they passing their genes on to, it is well established that it is a power thing but rape has been selected for because men who rape inevitably father children.

I don't agree with that, but have no arguement against it.
I think it is horrible to name rape as a natural behaviour in order to procreate. It's not advantageable as I see it, but I have no strong arguement against it from a scientific point of view.

Apart from the conscious decision to have a baby with a partner, no one thinks about their behviours in terms of passing on genes but if you subscribe to selfish gene theory, everything we do is somehow related to passing on our genes.

Like everything from eating breakfast at 2 pm to laying flowers on your dead mother's grave? Or buying the latest Chrysler Neon model because it has all you've ever dreamed of? Well, it says everything... I'm not assuming that selfish gene theory is what you rely on. It certainly isn't my cuppa tea.

And please not I'm not saying that rape is a good thing because I think there is an evolutionary reason for it.

But why does rapis behaviour exist? In nature, all qualities exist because they are advantageable, actually preferable. Those that are not die out after generations.

Would you say that rape as an instinct to reproduce was more common among our ape ancestors for instance and that we have evolved to disfavor that kind of behaviour? Then there must be a reason why this type of behaviour became unpopular.

John

Vangelis wrote:

Would you say that rape as an instinct to reproduce was more common among our ape ancestors for instance and that we have evolved to disfavor that kind of behaviour? Then there must be a reason why this type of behaviour became unpopular.

It didn't become "unpopular". It would always be a fringe part of behaviour as those who partner normally (or the alpha male in a system) would be protective of their mates and offspring. However the odd animal that does rape would have been a reproductive advantage for that animal and its offspring (provided the offspring wasn't killed by the alpha male). Nowadays in humans it is obviously not a viable strategy but you can't turn off 4 billion years of evolution just because it's against the law, sad but true.

I think you're confusing rape being wrong socially as opposed to it being wrong reproductively. Yes it is horrible to call it natural but it wouldn't exist if it wasn't natural. I do not think that all things that are natural are good, rape is like a disease, it happens but I'd like to see it eradicated.

John

tortega wrote:

Interesting reading on this subject

http://en.wikipedia.org/wiki/Sociobiological_theories_of_rape

Very interesting read, they're the points I was trying to get at but written far better.

Vangelis

tortega wrote:

really.

No..?

If rape is natural behaviour, then why shouldn't we accept it?
It is after all advantageable(read Wikipedia-article).

samb

They note that since the human brain itself, and thus all capacities for any kind of action whatsoever, evolved from natural selection, the only point of dispute is whether rape is only a by-product of some other unrelated adaptation (such as a desire for aggression, domination, etc.) or if rape itself is an adaptation favored because it increases the number of descendants of rapists. They argue that the latter case is true. from the link below

vangilis;
No..?

If rape is natural behaviour, then why shouldn't we accept it?
It is after all advantageable(read Wikipedia-article).

I still don't think you understand evolution, vangilis. It is advantagous to the genes, they get reproduced more, and therefore increase in frequency within the population. It is not advantagous to the type of society I would like to live in, or any reasonable person. It is wrong because it violates the rights of woman to have control over there own bodies. Our intelligence, empathy and Morality are also natural constructs of brains, hopefully we can use them to counteract the more undesirable characteristics of human nature.

I think your misunderstanding might be based on a belief that evolution is based on the good of the species. This is wrong, it is about gene frequencies within gene-pools.

Vangelis

samb wrote:

I still don't think you understand evolution, vangilis. It is advantagous to the genes, they get reproduced more, and therefore increase in frequency within the population. It is not advantagous to the type of society I would like to live in, or any reasonable person. It is wrong because it violates the rights of woman to have control over there own bodies. Our intelligence, empathy and Morality are also natural constructs of brains, hopefully we can use them to counteract the more undesirable characteristics of human nature.

I think your misunderstanding might be based on a belief that evolution is based on the good of the species. This is wrong, it is about gene frequencies within gene-pools.

Okay, my idea was the evolution should be to the good of the species. But is not the advantage of reproduction, the advantage of the species as a whole? The characteristics of a species lie in its gene pool. How come there is a difference between the standard the genes and the whole species?

One last question: Why then does not our biology create the society we want? Is our biology not reflected in the society we live in?

If not, then what is society?

Vangelis

tortega wrote:

Vangelis how do you speak with such certainity on this subject? Can you reference any of the claims you make?

What do you define as qualities and what do you define as "advantageable"?

I have read webpages and my own textbooks. Obviously I have got some things wrong, but hey I keep learning.

Advantageable would be those genetic traits that develop the species and make it viable in any environment. For giraffes for instance, it was advantageable with long necks, I know that, to reach the tall trees. So those with shorter necks were not selected for mating. What is advantageable is preferable to mates. That is what I know.

samb

Okay, my idea was the evolution should be to the good of the species. But is not the advantage of reproduction, the advantage of the species as a whole? The characteristics of a species lie in its gene pool. How come there is a difference between the standard the genes and the whole species?

One last question: Why then does not our biology create the society we want? Is our biology not reflected in the society we live in?

If not, then what is society?

Your idea that evolution should be for the good of the speices is wrong, society would be better if you were right but that is not the reality. Evolution is about advantagous (for reproduction) genes reproducing more and therefore increasing within the population. As already said, genes for dendancies such as rape, agression, whatever, will be present if they are beneficial to those who hold those genes in terms of reproduction. Tendancies for undesirable behavours will therefore be present unless we somehow stop everybody with these tendancies reproducing ( this would of course be unethical).
Why would our biology create the society we want?
this discussion does not change the meaning of society, consult your dictionary.

I have read webpages and my own textbooks. Obviously I have got some things wrong, but hey I keep learning.
good atittude

Advantageable would be those genetic traits that develop the species and make it viable in any environment.

NO the genetic traits that get passed on to the next generation are the ones that are beneficial to the individuals.
For giraffes for instance, it was advantageable with long necks, I know that, to reach the tall trees. So those with shorter necks were not selected for mating. What is advantageable is preferable to mates. That is what I know.
the giraffes with the longest necks reproduced more, it was not because they were doing it for the good of the speices. the mates chose them because they were the strongest.

GuanYin

Vangelis wrote:

Advantageable would be those genetic traits that develop the species and make it viable in any environment. For giraffes for instance, it was advantageable with long necks, I know that, to reach the tall trees. So those with shorter necks were not selected for mating. What is advantageable is preferable to mates. That is what I know.

Proto-giraffes most likely died out because they couldn't compete for food. They would have died due to malnutrition, weakness due to starvation and directly due to starvation.

They wouldn't have been "picked" or "not-picked" or "preferable" or "non-preferable" for mating. They just were phased out because they didn't survive in a world where the only available food required long necks.

Hence "survival of the fitest".

Vangelis

samb wrote:

Your idea that evolution should be for the good of the speices is wrong..

I know!!! So I have abandoned that idea allready.

Evolution is about advantagous (for reproduction) genes reproducing more and therefore increasing within the population. As already said, genes for dendancies such as rape, agression, whatever, will be present if they are beneficial to those who hold those genes in terms of reproduction. Tendancies for undesirable behavours will therefore be present unless we somehow stop everybody with these tendancies reproducing ( this would of course be unethical).

Why would that be unethical? There have always been individuals with behaviours that do not fit our social norms. And they keep coming. Denying people who carry genes that may develop these behaviours would be a good solution, no? So we did not have to bother with all the harm they cause and waste of money.

Why would our biology create the society we want?
this discussion does not change the meaning of society, consult your dictionary.

I don't know, I asked you. I don't need to check any dictionary.

Advantageable would be those genetic traits that develop the species and make it viable in any environment.

So genetic traits profit the species as a whole.

the giraffes with the longest necks reproduced more, it was not because they were doing it for the good of the speices. the mates chose them because they were the strongest.

It benefited the species as a whole anyhow, making each individuals more viable as generations passed by and the short-neckers were selected away.
The idea that reproduction should benefit the individual alone sounds very much like it comes from the selfish gene theory. Is the total benefit just a casual side-effect?

psi, yaaaa... okay. Just to let you know that I have read your post.
The fact that I don't reply to all posts does not mean that I ignore them.
But you don't think that I will write a whole post saying "Yes, understand.. Okay, got it... That's well said.." That'd be a waste. Just like weaker individuals are a waste of our efforts, eh?

homah_7ft

Have you been reading any of the posts? Genes survive because they enable the holder of the genes to pass on the same genes through living longer leading to more years of reproduction as an example. I know I've said it before but it's worth saying again. There is no foresight to evolution. It does not think. It does not exist for the betterment of a species. It's a process that exists due to basic mathematics.

GuanYin

Vangelis wrote:

Just like weaker individuals are a waste of our efforts, eh?

Please show me one post where I suggested this?

As far as I can remember you are the one who suggest eugenics as a way forward.

Vangelis

psi wrote:

Please show me one post where I suggested this?

I never said that you suggested that. They were my own words. There we are even. I misinterpret you, you misinterpret me. This is dull.

As far as I can remember you are the one who suggest eugenics as a way forward.

Correct.

samb

Advantageable would be those genetic traits that develop the species and make it viable in any environment.
So genetic traits profit the species as a whole
You were quoting yourself to back up your agrument now, please

samb

Why would that be unethical? There have always been individuals with behaviours that do not fit our social norms. And they keep coming. Denying people who carry genes that may develop these behaviours would be a good solution, no? So we did not have to bother with all the harm they cause and waste of money.

Genetics is not as deterministic as you think, or as we may have misled you to believe. For example, if a violent, murdering, rapist has children, these children may have some tendancies towards violence etc but if they are brought up well, with morals and a stable happier temperment then those tendancies may not manifest themselves. In fact I think that all men may have these tendancies to differnet extents and that it is to a large extent the circumstances within which they live that will determine thier behavour.

Another good, and topical, example would be that of paedeophilia. Judging from the frequency of paedeophilia within priests in Ireland it seems that these paedeophic tendancies are fairly common within men. Most men attracted to children will however know that it is wrong to act on thier feelings and therefore will not. These feelings may also be rarer within such men because they can ingage in normal sexual relations with mature woman. With catholic priests however, the celicaby may lead them to an obsession with sex, also children are easy victims for someone who is not supposed to have sex at all.

Is the total benefit just a casual side-effect?
Exactly