Excerpt: “It took hundreds of millions of years for plants to become such proficient vitamin C manufacturers, but vitamin production can change in far less time. Our own ancestors needed just thousands of years to alter their production of vitamin D.
When humans left equatorial Africa and spread to higher latitudes, the sun was lower in the sky and supplied less ultraviolet light. By evolving lighter skin, Europeans and Asians were able to continue making a healthy supply of vitamin D.”
My comment: Is there any current evidence from the fossil record or mitochondrial DNA that supports the old Out-of-Africa story. Is there any experimental evidence that shows how Europeans and Asians “evolved” lighter skin so that they could alter their production of vitamin D? Is the evolution of skin color like the evolution of plumage color in birds? If so, were birds black in Africa before they migrated into Europe and Asia?
Did skin color first evolve in Africa via mutations that caused it to become darker? Did mutations then cause skin color to change as Africans automagically evolved into Europeans and Asians?
Is anyone willing to ask Carl Zimmer questions like these, since he blocks my comments?