What separates humans from apes?

@Dave Allen,

Dave Allen;66331 wrote:

They could change into shrew like animals, but it would not be reversion - it would be a new species entirely.

---------- Post added at 06:33 AM ---------- Previous post was at 06:29 AM ----------

I wrote a fairly long answer - but for some reason it requires moderation before posting - can't think why though I did include some links to a blog about albino africans.

Hopefully it'll be approved shortly.

The reason for moderation is most likely due to the length of your post, Shorten it and repost it, it will appear pronto, trust me it will

I am not a moderator but had this exact problem , so I try to condense my posts as far as possible

@Alan McDougall,

Alan McDougall;66336 wrote:

The reason for moderation is most likely due to the length of your post, Shorten it and repost it, it will appear pronto, trust me it will

I am not a moderator but had this exact problem , so I try to condense my posts as far as possible

Alan wheres this grave?xris,im really interested..

@xris,

xris;66327 wrote:

Dave how do you explain all the blue eyes coming from one individual.

Well, I'll try again. Blue eyes are the result of a lack of melanin in the pigment of the eye. There are blue-eyed africans, but they are albinos. Lack of melanin pigment in the iris makes the eye look blue because the blood vessels in the eye have a blue coating.

People in countries without much sunlight, such as the temperate or polar regions, have an evolutionary advantage if they lack melanin, because pale skin picks up vitamin d from sunlight more easily than dark skin (hence why dark-skinned people in Scandinavia used to suffer a lot from rickets until vitamin supplements were discovered and made available).

So genes that "switched off" melanin production were advantageous for people in such climes.

According to Blue-eyed humans have a single, common ancestor w i n d y h a r b o r . c o m

"Originally, we all had brown eyes", said Professor Eiberg from the Department of Cellular and Molecular Biology. "But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a "switch", which literally "turned off" the ability to produce brown eyes".

...

Variation in the colour of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes. "From this we can conclude that all blue-eyed individuals are linked to the same ancestor," says Professor Eiberg. "They have all inherited the same switch at exactly the same spot in their DNA." Brown-eyed individuals, by contrast, have considerable individual variation in the area of their DNA that controls melanin production.

---------- Post added at 08:22 AM ---------- Previous post was at 08:18 AM ----------

xris;66341 wrote:

Alan wheres this grave?

I think it was a riverbed, not a grave, that people thought contained human and dinosaur footprints found together.

However, it's since been found that the human footprints were either partial dinosaur footprints, or were forgeries carved by locals.

@Dave Allen,

Dave Allen;66342 wrote:

Well, I'll try again. Blue eyes are the result of a lack of melanin in the pigment of the eye. There are blue-eyed africans, but they are albinos. Lack of melanin pigment in the iris makes the eye look blue because the blood vessels in the eye have a blue coating.

People in countries without much sunlight, such as the temperate or polar regions, have an evolutionary advantage if they lack melanin, because pale skin picks up vitamin d from sunlight more easily than dark skin (hence why dark-skinned people in Scandinavia used to suffer a lot from rickets until vitamin supplements were discovered and made available).

So genes that "switched off" melanin production were advantageous for people in such climes.

According to Blue-eyed humans have a single, common ancestor w i n d y h a r b o r . c o m

"Originally, we all had brown eyes", said Professor Eiberg from the Department of Cellular and Molecular Biology. "But a genetic mutation affecting the OCA2 gene in our chromosomes resulted in the creation of a "switch", which literally "turned off" the ability to produce brown eyes".

...

Variation in the colour of the eyes from brown to green can all be explained by the amount of melanin in the iris, but blue-eyed individuals only have a small degree of variation in the amount of melanin in their eyes. "From this we can conclude that all blue-eyed individuals are linked to the same ancestor," says Professor Eiberg. "They have all inherited the same switch at exactly the same spot in their DNA." Brown-eyed individuals, by contrast, have considerable individual variation in the area of their DNA that controls melanin production.

---------- Post added at 08:22 AM ---------- Previous post was at 08:18 AM ----------

I think it was a riverbed, not a grave, that people thought contained human and dinosaur footprints found together.

However, it's since been found that the human footprints were either partial dinosaur footprints, or were forgeries carved by locals.

I can understand the necessity but why the switch?how can nature decide blue is best?I can see maybe two or three being our blue eyed ancestors but just one?I cant imagine the chances of one person carrying that gene, it not being a dominant gene amongst so many brown eyed humans, surviving.How can we tell there was not more of these blue eyed individuals from nearer the beginning of humanity? Was anyone around to look?

@Alan McDougall,

They aren't arguing that there was only one person with the gene, but simply saying that all living people with blue eyes can be traced, using mitochondrial DNA to a single source.

So there may well have been others who had the gene, but they have no surviving descendents.

Whereas those who do have the gene are all descended from one person.

That's what the university of Copenhagen reckons, anyway. They base it on the staggering unlikeliness of exactly the same mutation taking place twice independently of familial relationships.

It's the same sort of method used to trace us back to mitochondrial Eve, or Adam.

Nature doesn't "decide" blue is best, but instead natural influences and challenges favour (ever so slightly) people with blue eyes - and other signs of low pigmentation - in sunless climes.

@Dave Allen,

Dave Allen;66348 wrote:

They aren't arguing that there was only one person with the gene, but simply saying that all living people with blue eyes can be traced, using mitochondrial DNA to a single source.

So there may well have been others who had the gene, but they have no surviving descendents.

Whereas those who do have the gene are all descended from one person.

That's what the university of Copenhagen reckons, anyway. They base it on the staggering unlikeliness of exactly the same mutation taking place twice independently of familial relationships.

It's the same sort of method used to trace us back to mitochondrial Eve, or Adam.

Nature doesn't "decide" blue is best, but instead natural influences and challenges favour (ever so slightly) people with blue eyes - and other signs of low pigmentation - in sunless climes.

It still seems pretty damned hard to swallow one person was responsible for all those with blue eyes.When you have one brown ,one blued person the dominant gene is brown.The likely hood of those blues expanding really pushes the credence of this theory.Why in other parts of the world, just as cold and dark ,did blues not become common.This pointing to one individual,gives evolution theory more problems than it solves.I would imagine more than one humanoid developing at the same time,did the whole of humanity hang by such small numbers?Does evolution usually make these leaps with just the one individual.Sorry im an evolutionist but it does sound a lot like Adam and Eve.

@Alan McDougall,

Dave, I haven't forgotten you. Been a little side tracked. New post a comin'. Ha.
William

@xris,

xris;66341 wrote:

Alan wheres this grave?xris,im really interested..

Has this happened to you? A post swallowed by a black hole?

Peace xris

@xris,

xris;66405 wrote:

It still seems pretty damned hard to swallow one person was responsible for all those with blue eyes.When you have one brown ,one blued person the dominant gene is brown.

Sure, but brown eyed people can carry recessive genes for blue eyes, which have a 50% chance of being passed down to their children, and this doesn't account for grey-eyed people or green eyes and so on (who have partial melanin pigmentation compared to those with brown eyes).

Quote:

Why in other parts of the world, just as cold and dark ,did blues not become common.

As you say the likelihood of the initial mutation for blue eyes is small. It was probably a massive fluke that it occured in caucasian people at all, and they are the people with less melanin in their systems than people in other parts of the world.

Inuit people, for example, actually benefit from having darker skin than caucasian people, because it can help mitigate the effects of snow-blindness, and the fact that the snow reflects sunlight - giving people who work on snow during sunny days twice as much sunburn as they might expect.

Quote:

This pointing to one individual,gives evolution theory more problems than it solves.

I don't see how it does, someone has to be the first person with a particular mutation. The gene for blue eyes is only very minor - it does not make blue-eyed people a different species or anything.

Quote:

I would imagine more than one humanoid developing at the same time,did the whole of humanity hang by such small numbers?

Well their would have been a time when populations of homnids would have been able to interbreed, but as populations drifted and became more genetically diverse this was no longer a possibility.

The video I posted called "Natural Selection Made Easy" explains this sort of thing.

@Dave Allen,

Initially brown eyed humans would not have carried the recessive blue gene because there was only the one blue eyed individual with no history of other brown eyed carrying the blue gene.One blue eyed individual breeding with brown eyed humans with no recessive blue genes makes it damned hard to explain its sudden rise.I do know a bit about the adaption of species but it does not explain a lot of what we see.I can see blue eyes affecting the colour range of eyes but was green first then blue or do all mixed coloured eyes originate from the one blue.Northern europe when the blue took dominance was as snowbound as Inuit lands but they never adopted the darker skin and Inuits never gave rise to blue eyes.I can understand the principles but should we ignore these strange anomalies?
If you visited Earth with this information you would with credence say humanity had injections of alien genes at certain times in its history.Certain Chinese carry European genes traced back thousands of years.Can we distinguish blue eyed genes as an alien injection when you consider the sudden rise of their numbers by one individual.If science had not made this claim of the one individual being responsible i would never contemplated this question.Its more than just a foot print in the mud of prehistory.

@xris,

xris;66500 wrote:

Initially brown eyed humans would not have carried the recessive blue gene because there was only the one blue eyed individual with no history of other brown eyed carrying the blue gene.

No, because the blue gene is recessive it could have been carried by a brown eyed person (whereas because brown eye genes are dominant they cannot be carried by people with blue eyes).

It may well not have been, but there's nothing to say it wasn't.

Quote:

One blue eyed individual breeding with brown eyed humans with no recessive blue genes makes it damned hard to explain its sudden rise.

Once there is a single blue-eyed individual that person will likely pass the gene to 50% of it's offspring even if the other parent has brown eyes.

These offspring will not have blue eyes, but will pass the gene to 25% of their offspring assuming they breed with someone without the gene, and 50% if they do (25% of which will have blue eyes).

Because breeding between relations was not so uncommon back then as it in countries like the UK today it is quite likely that the population in which the blue eyes first appeared was very interlinked - lots of great-granddaughters marrying great grandsons and so on.

Quote:

I can see blue eyes affecting the colour range of eyes but was green first then blue or do all mixed coloured eyes originate from the one blue.

It could be, but not necessarily, green eyes could be the result of a gene for partial melanin in the eyes, rather than fully as in blue eyes.

Quote:

Northern europe when the blue took dominance was as snowbound as Inuit lands but they never adopted the darker skin and Inuits never gave rise to blue eyes.

During the time humans lived there Northern Europe was never icebound year round like much of the artic. Cold winters and mild summers was pretty much the norm - so the advanges of dark skin vs snowblindness were not the same as pale skin to absorb vitamin D.

Quote:

If you visited Earth with this information you would with credence say humanity had injections of alien genes at certain times in its history. Certain Chinese carry European genes traced back thousands of years. Can we distinguish blue eyed genes as an alien injection when you consider the sudden rise of their numbers by one individual.

I don't personally believe interstellar travel is possible, or that alien species would bother buggering about with our DNA if it was - but I don't suppose it can be ruled out either.

Quote:

If science had not made this claim of the one individual being responsible i would never contemplated this question.

Well, we know mutations happen, a particular member of a particular species has to be first to have a particular mutation.

I mean, this stands to reason does it not?

If so, it's no surprise really that all forms of a particular mutation might be tracked back to a particular person? And professors at the uni of Copenhagen think they have found that blue eyes can be.

I'm not really saying they are definately correct - but I can't see why the theory is so controversial - for example, there must have been an early homnid who stopped walking on all fours most of the time, and started walking bipedally all of the time, and if that homnid has living descendants then we are all descendants of that homnid.

---------- Post added at 01:13 PM ---------- Previous post was at 01:11 PM ----------

As an easier example to grasp - dog breeders must have decided at one point - this dog is a breed called "cocker spaniel" - and if any pedigree cocker spaniels alive today descend from that dog then they all might (probably) do.

@Dave Allen,

Sorry to be dense Dave but you are saying, initially there was no blue eyed humans but brown eyed humans carried a blue eye gene before the blue eyed human existed? Then we had one blue eyed human who bred with a brown eyed human.What other genes are recessive that are waiting for a trigger to initiate a new type of human? How does this work with say the start of green eyed,do we carry the green eye gene as well as a blue, violet and all the other recessive genes necessary to create that colour.
Why was inbreeding not calculated to cause birth defects as it does now.It must have happened on an amazing scale for generations to create the numbers necessary, especially with the high mortality rate of this period in our history.

@xris,

xris;66665 wrote:

Sorry to be dense Dave but you are saying, initially there was no blue eyed humans but brown eyed humans carried a blue eye gene before the blue eyed human existed?

In the beginning there were no blue-eyed humans as far as we can tell. Brown eyes predominated (as they do in most other species of ape).

Because the allele (collection of DNA influencing a particular characteristic such as eye colour) for blue eyes is recessive it could have developed first in a brown-eyed person. There would have been no real way to tell without examining each individuals' DNA.

Each person has a pair of alleles for almost every characterisitc (though men lack certain pairs due to having a Y chromosome, but that's irrelevent for this). And the dominant allele will "make the choice" so to speak. So if a boy inherits or develops via mutation an allele for blue eyes from one parent and an allele for brown eyes from another - his eyes will be brown under normal circumstances.

However, he will have a 50% chance of passing the blue eye allele to his offspring.

Quote:

Then we had one blue eyed human who bred with a brown eyed human. What other genes are recessive that are waiting for a trigger to initiate a new type of human?

Lots of genes are recessive, such as those for sickle cell anemia, or certain hair colours. These genes can be good, bad or indifferent depending on circumstances.

As for what might arise in the future - who knows?

Quote:

How does this work with say the start of green eyed,do we carry the green eye gene as well as a blue, violet and all the other recessive genes necessary to create that colour.

I don't know really, I suspect that green eyes are the result of partial melanin - and that will probably also be dictated by genes.

Quote:

Why was inbreeding not calculated to cause birth defects as it does now. It must have happened on an amazing scale for generations to create the numbers necessary, especially with the high mortality rate of this period in our history.

Inbreeding between close relations does carry a high risk of causing infertility and relatively extreme mutation and congenital disorders.

However, between family groups with regular access to a wider gene pool it needn't be a problem. For example, though I find the idea a bit distasteful, it's relatively safe for a family line to include the occasional marriage between cousins (who would almost certainly share some of the grandfather's DNA).

Indeed, if you think about the smallness of these groups, stone age villages and so on, it's quite likely everyone was related to each other - but not closely enough for inbreeding to cause too many problems. As you say, infant mortality was high - so sickly children would have been taken out of the gene pool pretty quickly.

Cultural factors could have also had a part to play - for example some people find blue eys more attractive than brown - the colour, which is very rare in nature, could have been seen as having some divine origin, linked to gods of the sea or the sky. We just don't know, but this sort of thing has happened before.

For example, some native american tribes venerated albinos, and albinos were allowed to stay at home whilst the other members of the tribe hunted (probably linked back to the fact that albinos can sicken if they recieve too much sunlight). A predictable upshot of this was that albinos became quite common within this culture - as they had a lot of time to themselves with the women of the tribe.

@Dave Allen,

Thanks Dave for your patience and your in depth knowledge.I dont think i asked one question correctly.Lets say we had only brown eyes, do they carry any other recessive genes for coloured eyes.Do we carry all the recessive genes for all the diverse colours to become possible.I could understand if the recessive gene was present and then when the one blue eyed person arrived it would trigger a large number of blue eyes and i can then also understand why all blue eyes are related to that individual.If alternatively these genes where not present i can not believe they became prevalent enough to survive in such numbers.It really is an intriguing detective story, a lot younger and i might find myself drawn into the mysteries.Thanks again Xris

@Alan McDougall,

It may be that there are firther factors that contribute to eye colour than just the gene that decides whether or not we have blue eyes.

That gene seems to be pretty binary, if you have the gene you have blue, if not, you have some other colour.

That same allele may well influence, or fully decide, whether or not you have eyes that are hazel or green or whatever (I even used to have a friend with one eye that was almost orange, and another which was green).

So it's possible, in short. I really don't know enough on the particular allele to know whether or not it is responsible for all eye colours. Indeed, according to this blog (Google Image Result for http://mathildasanthropologyblog.files.wordpress.com/2008/07/albino_african_americans.jpg) multiple genes could affect multiple parameters:

Most of the novel variants presented in this study demonstrate signs of positive evolutionary selection in people of European origin, and those contributing to lighter pigmentation of the skin appear to have been under the strongest selective pressure. Intriguingly, some variants contribute to variation in just one trait; others to two or three. Among the findings of the deCODE group is a SNP on chromosome 14 in the SLC24A4 gene that is associated with increased likelihood of blond as opposed to brown hair and blue as opposed to green eyes. A SNP on chromosome 6p25 is associated with an increased likelihood of freckles and skin sensitivity to sunlight, as well as to brown hair. A sequence variant near the KITLG gene on chromosome 12 is associated with an increased likelihood of having blond rather than brown hair. One SNP in the tyrosinase gene is associated with freckling, and another associates with the likelihood of having blue as opposed to green eyes, as well as to skin sensitivity to sunlight.
The deCODE team has also provided detailed support for the previously reported association in the MC1R gene with red hair, freckling and skin sensitivity to sun. Similarly, the well known association of variants near the OCA2 gene with eye and hair colour, was replicated but also substantially refined. Taken together, the variants described in this report enable prediction of pigmentation traits based upon an individual's DNA.

@Dave Allen,

I return to this subject as i have seen we may have history of visitors of alien origin who had blond hair and naturally blue eyes.This god like fascination of the tall blond alien in other cultures is evidence enough to consider this as debatable.Now dont get me wrong im not convinced of its value but is it possible?
Can we really say that blue eyes and their derivatives came from one individual? Its an interesting subject that has now been exposed by gene research as highly impossible.
If we looked at it on a localised isolated island among other islands and we had an alien gene that caused blue eyes we would conclude an outside input, so why not with the evidence we have now?

@Alan McDougall,

So; let's debate it...Okay...I'm done...

@Fido,

Fido;72545 wrote:

So; let's debate it...Okay...I'm done...

Was that supposed to be impressive?

@xris,

xris;72662 wrote:

Was that supposed to be impressive?

No; dismissive... The thought that we might be the spawn of alians is not philosophy, but fantasy... Granted, newborns always look like aliens, and they have that dreadful alien habit of crapping in their space suits, and if it is made, they can break it, and if it is minted they can spend it... But; you know they are simply defects escaped from some asylum for the insane... As far as their appearance...You must understand that what you see is not what we have had...Humans are extremely inbred, mostly from being born and raised in issolated communities surrounded by enemies.... That is the crib of human childhood... Blue eyes were like so many defects we carry with us... Look at the genetic illnesses of the Jews who were only for a short time dispersed around the mediteranian...The dangers of inbreeding are notorious, and yet people still do it, and must often be prevented from doing it...Look at how much inbreeding occured in Genesis...I do not think that was abnormal...And it is easy enough to account for all adaptations good and bad to this single form of behavior....
I will point out that primitive peoples have a dread of incest, perhaps because they were already more inbred, for living in even smaller groups...More settled people often engaged in at least some over breeding, perhaps, as around this place, for comfort, but also to preserve large tracts of property...

@Fido,

Fido;72689 wrote:

No; dismissive... The thought that we might be the spawn of alians is not philosophy, but fantasy... Granted, newborns always look like aliens, and they have that dreadful alien habit of crapping in their space suits, and if it is made, they can break it, and if it is minted they can spend it... But; you know they are simply defects escaped from some asylum for the insane... As far as their appearance...You must understand that what you see is not what we have had...Humans are extremely inbred, mostly from being born and raised in issolated communities surrounded by enemies.... That is the crib of human childhood... Blue eyes were like so many defects we carry with us... Look at the genetic illnesses of the Jews who were only for a short time dispersed around the mediteranian...The dangers of inbreeding are notorious, and yet people still do it, and must often be prevented from doing it...Look at how much inbreeding occured in Genesis...I do not think that was abnormal...And it is easy enough to account for all adaptations good and bad to this single form of behavior....
I will point out that primitive peoples have a dread of incest, perhaps because they were already more inbred, for living in even smaller groups...More settled people often engaged in at least some over breeding, perhaps, as around this place, for comfort, but also to preserve large tracts of property...

I appreciate your dismissal but it does not answer the questions of our genetic history.I would not have contemplated it if i had not been told all blue individuals had originated from one individual.Then i cant understand how we all originated from one other individual.Does the whole of humanity depend on the survival of one women who happened to be the first homosapien.If green eyes are a mutation why did they not become more prevelant,the story of our ancestors may not be alien but we have a long way to go before we explain these mysteries.Genetics it appears is causing more questions than it gives answers.

Philosophy Forum

What separates humans from apes?

Quick Links

My Account

able2know