Genetics, ethnicity and the evolutionary causes for physical variation amongst ethnic groups?

I came across a similar question as this, asking 'why black people have big lips' on this network; although I feel this question was inspired by honest curiousity, the 'questioner' received much in the way of slander, being branded as 'racist' etc. by those who can only be described as naive, and received very little in the way of actual 'answers'. I would like to make it plain that avoiding these questions (especially branding those that ask as biggots) furthers racial taboos and seperation and that to be curious about such things is only natural; therefore serious answers only please.

Is anyone aware of any grounded evidence to suggest an evolutionary reason for phenotype variation, for example i'm sure we're all aware that afro hair types better insulate the owner from the sun. Moreover, what about other physical characteristics, the generalised angularity of caucasian structure as opposed to more rounded african structure, smaller asian frames etc?

Genetics, ethnicity and the evolutionary causes for physical variation amongst ethnic groups?

Well, it is well known that tannin allows greater resistance to sun exposure. So there is a variation easily paired with a reason. Some people hold a lot of body fat (not due to medical condition), and this clearly has pluses and minuses-greater fuel stored, but reduced maneuverability, and crosses all ethnic lines. So within groups, and between groups there may be some racially genetically intrinsic markers with no clear-cut purpose, but many that have purposes, and many that display a common genetic tree.

Genetics, ethnicity and the evolutionary causes for physical variation amongst ethnic groups?

I think physical variation is the proper term. Since all humans are inter-fertile that rules out evolutionary causes. Environment and isolation are definite factors. Natural barriers to travel seem to close the breeding pool. But modernity is eliminating those factors. I don't see any room for evolutionary causation.

Genetics, ethnicity and the evolutionary causes for physical variation amongst ethnic groups?

Curly, kinky hair does not mat easily and allows for air circulation over the skull. This in turn helps to cool the blood and the body. Wide nostrils allow for increased airflow into and out of the body. this also helps to cool the person. The bigger lips allow for more blood to be near the skin surface and again helps to cool the blood and the body.

Genetics, ethnicity and the evolutionary causes for physical variation amongst ethnic groups?

ethnicity is a moot point because your all ready looking at variation among ethnic groups. An evolutionary cause is an external one that effects the genetic make-up of a population. Genetics alone is an interal cause with the reproduction or passage of different genes though a population. Also what kind of evolution causes are we talking about? evolutionary changes that can occur with the organism can be caused by external and internal factors. Genetics is by its definition, can be be viewed as a catalyst rather than a cause in of its self. Therefore your only really looking for evolutionary causes.