Evolution: Human Hair, glitch?

[jungjedi]

Originally Posted by Boerseun

Hair is exclusively a mammalian invention. No other animal has hair.

yep.dinasours may have even been warmblooded

[arkain101]

A friend of mine shared an article he found related to this topic.

Don't call it fur!

After combing the scientific literature, researchers conclude head hair and fur aren't the same

By Jim Dryden


Dec. 27, 2004 -- Mammals have fur over most of their bodies, but at some point during evolution, we humans lost that fur covering. Researchers at Washington University School of Medicine in St. Louis argue that hair on the head is somehow different from fur because fur stops growing when it reaches a certain length, but our head hair continues to grow. To drive home their argument, they ask in a recent article in the journal Evolutionary Anthropology, "Have you ever seen a chimpanzee getting a haircut?"

Neufeld AH, Conroy GD. Human head hair is not fur. Evolutionary Anthropology, vol. 13:3, p. 89, June 2004.
Don't call it fur!

[InfiniteNow]

Originally Posted by arkain101

Article Quote: To drive home their argument, they ask in a recent article in the journal Evolutionary Anthropology, "Have you ever seen a chimpanzee getting a haircut?"

Actually, yes...

[skuzie]

Hair is a byproduct of fish scales thinning out and loosing their original purpose in water for the purpose of heat capturing. The general rule of thumb is the colder it is the longer the hair 'or fur' will get, look at various animal species like dogs or bears. Our 'native' environment where we along side with monkeys evolved is of course Africa, which is warm. When we relatively recently migrated northward we encountered a more colder environment thus spurring larger hair growth.

[ErlyRisa]

I haven't read the whole thread ... but to me the answer is obvious.

Humans : From monkeys....

start losing hair, after they invent Fire.
they lose even more when they live in vast open spaces (african svanagh) -(africans today are almost hairless, even today (climate/proportion of sweat, would be a strong factor))

now humans move to other areas , which have different climates...

the Hair gene now has no idea what is necessary -- in grease it decided for a thin blanket, to hold sweat away from the skin in the ocean breeze... in the middle of Europe it decided that a minimal banket was necessary, especially so when Heavy clothing was used.

...so in effect the human genome has decided to evolve to allow for mutiple climatic circumstances that the individual may reside in.... the major question is what trigger the need for a variable length/blanket of hair.... it was the Fire.. wwhen the first monkeys were stressing thier bodies from very high heat to normal climating surrounding, the genome accomodated this constant sporadity.

--My cat is actually losing the hair near it's back - where It loves to sit right next to the space heater... and that's not even a single generative change....in order for the offsripng of my cat to be able to accomodate the sudden fluctuations of heat/cold they would need to be able to 'grow' and 'shed' a blanket.

Hairy People = semi windy warm climates (clothes are unnecessary, a little warmth from a thin blanket helps keep warm air at the skin in colder conditions, yet on hot days doubles as a semi effective radiator of body heat) -note, not a good scenario for high radiant heat climates, eg. South America, Africa.

Stubble Hariy People = high radiant heat from sun. -no good for winter conditions.

Hairless People = cloth wearers... the Europeans, the Chinese., note that the colder the climate (Russia) then some blanketing around the lower body is usually still called for, but because of cloth wearing on the heading, especially in the very cold climates, Head/Facial hair grows even less.


anyway... --you could write a book... it's all pretty darn logical, and am surprised that we would not already come to this conclusion.

[billg]

I like the idea of humans losing the hair on account of being too hot with lots of hair... not only from the climate (which I don't think could have been particularly different from other African primates) but also, I would suggest, because increased brain size; the brain in humans supposedly accounts for 20 percent of our energy demand while weighing only 2 percent, and it seems likely it generates a lot of extra body heat.

The argument that fire had anything to do with it seems pretty unlikely to me. Also maybe your cat shouldn't sit so close to the heater...

[ErlyRisa]

I think Fire has everything to do with it...

just like we use stemcells, and we 'Train' the cells into the body part we desire... the outershell (the skin and hair), re-trained itself to cope with the varied sporadic change.... it's only option was to use material as it could and grow hair as physically quickly as possible, but at the same time look for a happy medium(centre not material)

[arkain101]

and we 'Train' the cells into the body part we desire

which cell makes the choice?

when you say we, it seems to be excluding evolution theory, to say I train my cells. The theory says you are your cells.

[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.

[arkain101]

I have another inquiry.

As an example. Take the domestic cat. The cat of the house pet kind.

There are many breed types. Tabby, cal, black, white, and the like. Each cat is individually different from one another. However in all these differences, each cat that is capable to breed with eachother should be considered the same species, as they are able to reproduce.

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.

Using these examples lets look at a situation.

As we consider that a species must be capable to breed in order to survive, it is possible it must be the same species in order to do so.

If a species ever changed into a unique species, of which it can not breed with the blood line it came from, where is it going to breed, and start this new line of species?

For example, lets rewind in history. We go back to the first mamals.

Say we have a funky looking fish mammal that starts walking on the land. It needs to be able to reproduce. Either within itself, or with a mate.

Over time these species spread the land and physically adapt to their enviroment. So each mammal becomes slightly different. Some adapt for hotter dryer places, some adapt for colder wet places, some adapat for speed and agility because of preditors. However, each of these different looking creatures are linked as a species and can breed with eachother.

1)At which point can a species change and yet reproduce as the first of its kind?

2)Or the other option would be that each species came from a different line out of the ocean, and adapted all over the place.

Would #2 suggest that life started with millions of original seeds as it were and have only adapted since their begginning?

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 )

However, I have seen alot of people that don't look all that human, don't walk all that human, and don't talk all that human, but they came from a human, and must then still be a human. If it was not a human, its kind would die and become extinct unless it could self reproduce.

This is probably evolution in a nutshell. I havn't studied the subject much, so I wouldnt be sure.

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?