Evolution: Human Hair, glitch?

[arkain101]

Well after a little research I see it a little clearer now.

I was given the impression that evolution meant a large mutation at some point in one birth would be the requirement for a new species.

I gather now that it is rather the long term adaptation to enviroment that alters the genetic information to the point of interbreed is lost amongst its bretheren.

That makes alot more sense I suppose.

I should be able to theorise a little better on this subject, now. I would apreciate any more insight into this.

[billg]

Yes you're more coorect in that second post. You have to remember "species" is a human idea, and to most people most of the time a generalisation to make things a bit easier to understand. When you get down to the nitty gritty, it can become fuzzy. A single large mutation does not suddenly create a single organism of a new species - rather the genetic firequencies in two populations of the same species gradually become more different until they cannot breed. This could occur through geographical separation for example, where a group of animals migrates for some reason, and then it and the original group accumulate mutations until they are too different to breed.

It could also, potentially, happen by the chance distribution of a particular phenotype; say a group of proto-chimps has aggressive tendencies, and another group develops more pacifistic co-operative tendencies, and then cease to interbreed as their different social structures prevent them from doing so, and slowly change genetically until they can no longer interbreed.

I use these examples as in fact the two different species of chimps, the common chimp and bonobos, have these two different social tendencies, and are believed not to interbreed in the wild, though can breed in captivity.

Spring Meeting 2003

"From historical accounts it appears that natural populations of bonobos and chimpanzees have been allopatric since their phylogenetic separation. There are no accounts of hybridisation under natural conditions. There is, however, evidence for interbreeding between bonobos and chimpanzees in captivity. We briefly (6.5 hrs) observed and filmed a small group of four bonobo-chimpanzee hybrids (2 males, aged 10 and 9, and 2 females aged 10 and 8)."

Also, populations of chimps and bonobos in the wild are separated geographically by rivers both from each other and from different groups of each species.

Indeed the definition of species becomes even more problematic when you consider examples even less closely related animals interbreeding and creating fertile young, such as female tiger-lion hybrids (Ligers).

Wikipedia is always good.

Species - Wikipedia, the free encyclopedia

[CraigD]

Originally Posted by arkain101

However, as I understand not all cats can breed with eachother, and other animals can not reproduce with cats.

For example, a Lion can not breed with a household cat and create offspring.

While I agree it’s unlikely a lion and a housecat could be (obviously artificially) bred, it’s amazing how many verified successful cross-species hybrids among the cat family (Felidae) species exist. Hybrid viability appears to be related more to the gross size of the cat species in question than chromosomal structure and other genetic factors – house cat (typically 3-8 kg) and bobcat (7-14 kg) hybrids are well known, as are lion and tiger hybrids – “Ligers” an “tigons”. AFAIK, although such hybrids are typically bred naturally, they are not found in the wild, where distinct Panthera genus species are fierce, even lethal competitors, not potential mates.

Lion and housecats (with 38 chromosomes) are at least grossly genetically more similar than lions and tigers (with 36)

You see at this point I can not reproduce with any other species than a human. (as far as I know, Its not like I have been experimenting )

Bizarrely, this claim is not entirely scientifically supported. Present theoretical genetics suggest that human (23 chromosomes) and great ape (24 chromosomes) hybrids is about as likely as horse family (equidae) hybrids, such as Przewalski's Horse, and preliminary research shows that human sperm can reach and attache to the zona pellucida of ape eggs (but not of other primates, such as monkeys).

Although the ethical barriers to human-primate hybrids would seem to be nearly insurmountable, it appears to have been verifiably attempted in the 1930s. See the wikipedia article “Humanzee”.

Though speciation almost certainly occurs, and is a central feature of evolution theory, it appears to be not entirely due to reproductive molecular biology, but also have a strong social factor. Lions and tigers done interbreed in nature because they can’t, but because they don’t get along.

But I wonder, if life came from similar origins, does that ever mean it could return to something similar again, or is it forced and demanded to continualiously spread outwards in a diverse and increasing branch of different species?

My understand is that genetic diversity can only be reduced by reducing populations – “extinction bottleneck”. As long as the number of distinct genes in the genomes of all species remains high, the potential for there being many distinct species appears to be preserved, even if the actual number of living species is reduced. Noting that the vast majority of genes are of microscopic species, and the startling exchange of microscopic and large animal species, I suspect that even the complete extinction of large animal species would be only a temporary setback in the diversification of life.

[arkain101]

great replies...!

My brother and I were discussing a little on this topic and he said something interesting that I'd also add here.

It would seem as though in the animal kingdom, in order to be threatening or show dominance you must stand tall and erect in posture. As an animal you must show your dominance in posture.

He went on to mention, in the eye of the animal kingdom we as creatures must appear supreme in constant domination posture. Without effort we display total supremeity just in our natural manner of posture. Even greater so we may lift our hands and create many sounds, of which the animal kingdom should very commanly see as I am greater than all.

It was an interesting thought.

[silverslith]

I don't think hairs evolved much since combs were invented. So naturally evolved hair was dreads. They hold a lot of hair in a compact shape and fall off when they get too big or are abused by hard yards. They trap and radiate immune markers in sweat, giving potential mates info at a distance on what exotic immunities you can contribute to the offspring. Why the sweat of exotic male smells so good to women.
The Studs in the tribe that don't have to hunt much would grow the most luxurious ones- sign of social status.

[ErlyRisa]

Originally Posted by billg

We don't train our cells at all. Genes that lead to traits that confer an advantage to the organism are more likely to be passed on, that's all. What advantage would there be in having less body hair that occurred specifically around fire? Surely hairier individuals, if too warm, could just move further away from the fire... whereas, in times of excess heat caused by a warm climate, hairier individuals may be more likely to die of heatstroke or dehydration. Even in the shade temperatures can be very high, but you can simply stand a bit further back from a fire.

_I think Cancer itself... is the mind trying to 'change the body' , but the body 'miss-understanding' the instruction and doing something wrong.... It's, the last 100years of really advanced thinking in our society that is spawning evolution, beyond the bodies ability (Xmen)

As for apes.... But!

Standing Around the fire , and communicating, and being close to your fellow Chimp is what spawned civil tribal behaviour.
(Have you seen the Movie that the Drummer of the Beatles did, I think it was called "Caveman" or something or other.)
...and by having to be 'a part of the tribe' you had to be able to be able to cope with the sporadity of heat stress from the fire... hence the 'Training' of the outer shell (skin/hair) was a direct result of the sporadity and significant amplitude between diatic conditions (Yes ...Elephants are Hairless too... but our size is on a smaller scale than the big african animals... any animal of around our weight, finds it beneficial to have hair)
--The only reason our hair keeps growing, is the way in which that gene was constructed in the frst place... it's only option was to shed quickly, and grow as much as possible as quickly as possible.... it's probably why we have hair on the back of our heads that keeps on growing, because the top of our head, and our backs, were facing away from the fire. (ie, long hair to keep rear end warm)

---It's very simple and logical people!!

[ErlyRisa]

I wonder if some-one could correlate this data?

BALD MEN....

Women Chimps at the Fire...would have always been their (Even Today's Women Chimps are the socialites) ... so they would have grown, longer hair, especially so, because they didn't have to run around as much hunting (and also, as a byproduct mating Lyre tail?)

The men... they hunted, and gave each other the irrates, taunting, playing etc (just like the chimps of today)
Thier hair grew much the same, but because they had to hunt it didn't grow as quickly... which brings me to the cure for boldness...

Because the Gene for hair growth couldn't make up it's mind, especially for hunting men (were extreme head hair, hampers with listening ability and just overall hunting affectivness), the bolding man today is ...

A. Either the chimp that was the 'best hunter' .. able to listen the best.
or
B. The Extrovert chimp... that wasn't welcome at the fire, and had to hold onto his primordial hair cover (fur), and probably watched the fire from a distance... usually in a submissive position, with his head faced toward the fire (his bold spot was the hottest).

...I wouldn't mind proving this, by selecting a group of men and analysing, wether or not they have more back hair than the non hair receding man.(they would have kept a larger amount of hair on thier backss to keep warm while lying at a distance from the fire(trying to listen))

[billg]

Originally Posted by ErlyRisa

_I think Cancer itself... is the mind trying to 'change the body' , but the body 'miss-understanding' the instruction and doing something wrong.... It's, the last 100years of really advanced thinking in our society that is spawning evolution, beyond the bodies ability (Xmen)

How exactly do you propose the mind changes the body? There is no known natural mechanism by which the mind can willfully alter the genetics of the body. It's just not how evolution works.

Originally Posted by ErlyRisa

Standing Around the fire , and communicating, and being close to your fellow Chimp is what spawned civil tribal behaviour.
(Have you seen the Movie that the Drummer of the Beatles did, I think it was called "Caveman" or something or other.)
...and by having to be 'a part of the tribe' you had to be able to be able to cope with the sporadity of heat stress from the fire... hence the 'Training' of the outer shell (skin/hair) was a direct result of the sporadity and significant amplitude between diatic conditions

Once again, what is this "Training"? How does it happen? It is not something I've ever heard of, being able to "train" your genetics. Animals do not force themselves to evolve. They do not evolve traits because it makes them more comfortable. Animals evolve traits that give them a reproductive benefit. For this reason I think the argument that the heat of the day (being a much more likely cause of death than heat from a mere fire) as the cause of any such evolutionary pressure is a much better argument than fire having anything to do with it. I just don't believe the idea of apes dying or being unable to mate/hunt as effectively simply because they were too hot in front of a fire. Just don't stand so close...

As for your logic for baldness... I don't even want to get into that.

[silverslith]

those who can express genes good for the enviromental pressures are selected.

[ErlyRisa]

Cure For Baldness ... and what Darwin Left out (probably because he knew the world was not ready for it)

Before you do go bold (and you know you will, because your, father, grandfather, and even Mum are bald)

---When you have that feeling of being 'OutCast' ... find yourself a heat source and stand infornt of it. ... with a bit of luck the primordial 'Boldy Extrovert Gene' won't activate, because you have aleviated the 'feeling' of segregation. (alternatively, standing in a cirluar group of friends and participating could also help)

--Why the Chinese have 'less' of an occurance of boldness : thier society is 'less' based on Fuedalistic style segregation, alot earlier than what we europeans did.

--Why the nordics have long hair... they 'stuck' around the fire as humans longer than the rest of Europe.(and other continents)