S I N G I N G P E O P L E

Each day babies are born in every country on earth. The number of people, or the population, on our planet is increasing each year.

One of the most noticeable differences among people is the color or their skin. This color comes from tiny grains of melanin, a pigment found in the second and third layer of a person's skin. These grains are so small that, to the eye, they blend together and make the skin look smoothly colored. Many scientists think that the different shades of human skin evolved as a response to the sun's intensity.

Thousands and thousands of years ago, when only small tribes of people lived scattered across the tropical areas of the earth, the color of a person's skin could offer important protection from the powerful ultraviolet rays of the sun. To these early equatorial people, darker skin proved to be a shield from this danger. Survival depended on just such advantages, and dark-skinned people flourished. As people moved toward the poles, where winters are long and sunlight scarce, lighter-skinned people benefited from their ability to more easily absorb the sunlight necessary for a healthy body. More of these pale-skinned people survived the demands of winter, and successive generations in colder climates favored fairer-skinned people. Thus people's skin evolved to the range from very deep brown, or nearly black, to light brown, shades of beige, or even light pink, depending on where they lived on the planet. Scientists expect skin color to slowly continue to adapt to the changing conditions on earth.