In The Beginning

[whiskeryron]

Theory tells us that the human race started in a small area of Africa,if this is so where would each human find a partner to procreate with? Would we in fact be mating with brothers & sisters ? If not then where do the extra people come from ?

[Old_Geezer]

In a small community sex with relatives will be common. Unless regular raids on nieghbouring tribes allow one to kidnap non-related wives.

[dunnitall]

This is one question I've asked religionists before now....never had a suitable answer, maybe I will get one from your question whiskeryron.

[Canary42]

Evolution progresses by gene mutation in a single specimen - then the specimen mates with non-mutated but the dominant mutated gene recurs in the offspring, and so the new population grows, and if it has an advantageous feature it survives at the expense of the original unmutated one, or can co-exist alongside it.

[dunnitall]

Canary...but what about 'god' having created man in his own image....? Cough, cough..

[Canary42]

Cough cough indeed !

[whiskeryron]

Further to my original question, as the tribes spread to different parts of the globe, if the theory is sound why would people take on such differences in appearance ?

[dunnitall]

Ron do you mean as in Chinese, Japanese etc etc? A conundrum that's for sure as you would think everyone would look very similar wouldn't you.

[Canary42]

Not at all - just more beneficial mutations (e.g. black skin more resistant to UV light in very sunny regions, white skin survives in more temperate zones).

[jim360]

Also it's typical for subsets of a population to diverge a little from the rest of the population if they become isolated -- the basic point being that there is less room for genetic variation in a smaller group, so that any differences tend to be accentuated rather than "smeared out".

Then there's the fact that if that subset is living somewhere different then there are different evolutionary pressures -- for example people in the far north have no especial reason for high levels of melanin in their skin as opposed to those living in equatorial regions.

But anyway. The answer to the OP is basically "incest -- incest everywhere".

[Zacs-Master]

I never really know why people ask questions which can be easily researched rather than relying on speculation and opinions of the general public, on a forum.
http://scienceline.ucsb.edu/getkey.php?key=1138

[Canary42]

The Forum method can be more entertaining :-)

[whiskeryron]

I can understand skin changes etc. But why changes in eye shape & other facial differences ?

[jim360]

For example I think it's cheetahs that are supposed to have dropped to a population numbering in the hundreds at least twice in their past -- they only recovered in number through massive amounts of familial inbreeding, leading to a very low genetic variation. This isn't unknown in other species either.

[Old_Geezer]

Differing appearances due to differing local personal tastes. Local conditions may make certain features an advantage and this would be picked up by folk looking for a mate.

[Canary42]

That's a bit more tricky Ron, but it's surely possible that while the eye change itself did not confer advantage but as that feature proliferated, somewhere in the descendant population a further unidentified one did. Incidentally all this is highly speculative on my part, I'm not an expert in genetics.

[Canary42]

Good point OG.

[Khandro]

//Would we [sic] in fact be mating with brothers & sisters ? If not then where do the extra people come from ?

Of course, just like all the cats in my village.

[whiskeryron]

Don't know if anymore can be added, but thanks guys for a splendid discussion

[dunnitall]

So it's evolution all the way? That's more in keeping with what I think. However, how would religionists answer these questions or am I not allowed to ask lol?

[Khandro]

Depends which "religionists" you're talking about