Origin and colours of mankind

[pirwany]

If the human race started from Africa why are we of different colours and physique?

[heathfield]

It's called evolution. The characteristics of humans changed under the climatic conditions in which they lived. Cooler climate = longer nose to help warm the air entering the lungs. Too cold, and longer noses mean frostbite, so shorter noses for eskimos - but an added layer of fat round the eyelids to help protect the eyeballs from the cold. Dark skin for those in the tropics to help radiate excess heat from the body - not needed in cooler climates. Etc,etc.

[VHG]

That is like asking why all birds or dogs dont all look the same.

Darwin noticed this when he did his world tour, and led to his book Origin of the species.

For example he noticed birds of the same type had different types of beaks depening what type of food was available in the area.

[Scarramouch]

Lol VHG. I understand your point but it isnt a very good analogy funny that it is. Like most species we have evolved our distinct and differing characteristics by means of natural selection. Dogs have evolved theirs by means of selective breeding.

[jno]

so all dogs looked the same before people started breeding them because they wanted a long low dog like a dachsund or a nice hairy collie? I don't think so. Dogs evolved on their own same as us.

[Ankou]

i suppose it depends whether you go along with the Multiregional model or the Out of Africa model.

[Scarramouch]

incorrect. Until mankind interfered hundreds of years ago dogs did all look much the same. All breeds of dog were derived from the wolf. Selective breeding can have dramatic effects in a relatively short time. Something darwin himself observed with pigeons. A breed can be completely changed in as much as to be almost unrecognisable in about 6 generations.

[heathfield]

Wolves and wild dogs have evolved through naturat selection. Domestic breeds are the result of selective breeding. Mongerels are the result of interbreeding between selective breeds.
I remember a TV programme some years ago about a Norwegian who keeps wolves. He reckoned he could replicate any present-day domestic breed by selective breeding, starting from pure wolves, in 6 to 10 generations.

[jno]

I don't want to underplay human breeding efforts (which I think go back thousands rather than hundreds of years) but as fair as I know dogs are capable of evolving on their own

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

[Scarramouch]

i dont think anyone would argue with that jno. Of course given the chance they would have evolved. But they would not look like any breed we know today and given the timesscale wouldn't have strayed too far from the wolf. This isnt a a matter of opinion mate. Its a statement of historical fact. Research it yourself.

[Ankou]

I remember seeing a programme quite a while back about breeds, and it did claim that the Victorians manipulated breeds by doing some horrid things to them to try to control their short term evolution. I don't know how true that is and cant seem to find anything to back it up, but I do remember claims such as severing muscles etc to stem growth and height and leg length. If I find something I will post a link.

[dundurn]

Ankou - the Victorians, and later dog breeders, have done all sorts of things to make their animals look different - ear cropping and tail docking, for example. There are also the "lesser offences" of poodle cuts and tartan coats. None of these, however, have any effect on the animals' evolution, neither long nor short term. Only genetic effects can be transmitted from parent to offspring.