Particularly significant given the Out of Africa Theory currently in vogue
and well substantiated by paleanthropological, linguistic and genetic data.
Emerging from sunny Southern Africa approx 120,000 years ago, it is
estimated we were in Europe by circa 60,000 years ago. Thus our diurnal
variations may be more attuned to that previous sunny climate and subtle
variations ensue ... .
"Wayne Alan Simon" <ariess at bellsouth.net> wrote in message
news:lSbha.71399$d15.34079 at fe06.atl2.webusenet.com...
> Many biological systems are effected by daylight or lack thereof. Some
> turned on and off via the light. Some are increased or decreased from
> ( various sources and wavelengths). Evolving on a planet that for the
> part has day and night cycles, has also allowed for various adaptations or
> maladaptions based on the planets light darkness cycle. Of course if you
> live in an area that is light half the year and dark half the year, you
> find your biological systems adapted quite differently. Diurnal
> in most neurohormonal and endocrine systems is the rule and not the
> exception. Vitamin D, as mentioned many times is just one factor of many.
> The situation is complex, and to shed a little "light" on the subject is
> always enlightening!