I am red-haired, with blue
eyes with a pale, freckled skin that burns easily, so it is clear that Tropical
Africa is hardly my natural environment. In fact, I am a rather typical common
or garden human specimen originating from North West Europe. So why do so many
Northern Europeans have blue eyes, fair or red hair and a pale skin? Why are
Scandinavians and the Dutch so tall in comparison to other people?
Stinne Andreasen put these
questions to Peter K A Jensen of the University of Aarhus in Denmark. Dr Jensen
has been involved in the study of the origins of humankind and our development
for most of his life The answers to these questions he says are to be found
thousands of years ago with all our ancestors. These were the first modern
humans who lived in the Southern part of East Africa many thousands of
years ago.
All people on earth today can
trace their ancestry and origins back 50-60 000 years ago to this place in
Sub-Saharan Africa before spreading ourselves all over the world. Then, each
one of us had brown eyes, dark hair and dark skin to protect us from the sun’s
ultra violet rays.
SKIN
So how did pale skin come
about? Jensen reckons this began 10-15 000 when the first people from
Africa settled in Europe at the end of the Ice Age so even then there was not
much sunlight around and precious little in the winter. This was a problem as
these first Northern Europeans needed sunlight to make Vitamin-D for their
bodies. Over time they developed a lighter skin colour that could more easily
absorb Vitamin-D from the sun than in the past.
Of course there are
exceptions; the Inuit do not need pale skin. They get enough Vitamin D from
their diet, from seal, whale and liver, so do not need the vitamins from the
sun.
In contrast Australian
Aborigines are overwhelmingly light in colour; but that is because many are of
mixed-descent, having European ancestors.
HAIR
What about fair and red hair?
We do not know as much about this as our skin, but there is a clear relationship
between skin type and hair colour. Some of the gene mutations that give rise to
very pale skin also give rise to fair and red hair. But it is more complex than
just that.
EYES
And blue eyes? Again we do not
know for certain why blue, grey and green eyes are so common in N Europe. The
most rational explanation again is probably natural selection, reproduction and
adaptation. Just as pale skin was exotic, so were blue eyes so they had a
better chance of reproducing themselves than brown eyes. But the vast majority
of humankind have brown eyes.
HEIGHT
Northern Europeans’ height has
increased in the past 100 years due certainly to improved social and living
conditions and better nutrition but N Europeans are on average several
centimetres taller than Italians or Spaniards. There has been little change in
average heights since 1980s, so Europeans have probably reached their maximum
possible heights given our gene pool. There are also climactic and topographic
reasons in considering why some peoples are taller than others.
If you live in a hot dry place
you need to be able to lose heat quickly to avoid overheating. A tall thin body
ensures the body’s surface area is greater in relation to your mass and allows
a faster loss of heat. The Masai are some of the world’s tallest people as they
are built to survive the dry open savanna in Sudan, Kenya and Tanzania.
If you live in the Arctic you
tend to be small and squat. The Inuit and Laplanders have a relatively small
body surface area in comparison to their mass so it is easier to keep warm.
MASS
Why are Northern Europeans so
heavy? Yes, they live in the richest and most developed part of the world. Yes,
they eat too much and do not exercise enough. But that is not the whole reason.
Our African ancestors weighed between 30-40 kilos.
So modern Northern Europeans
weigh less than Neaderthals but more than their parents or grandparents because
we have got fatter. This tendency has grown in the recent past and will probably
continue in the years to come.
