Why does skin color vary with latitude?

As latitude increases, the amount of light reflected by the skin increases. This shows that skin gets lighter farther from the equator. This graph shows how skin color (as measured by light reflectance) changes with latitude.

Why did dark skin evolve near the equator?

As people moved to areas farther from the equator with lower UV levels, natural selection favored lighter skin which allowed UV rays to penetrate and produce essential vitamin D. The darker skin of peoples who lived closer to the equator was important in preventing folate deficiency.

What was the initial reason for diversity in skin color?

Theory held that darker skin had evolved in order to afford early humans—who had recently lost the cover of fur—a protection against skin cancer under the tropical sun.

What was the skin color of the first humans that originated in Africa?

Researchers agree that our early australopithecine ancestors in Africa probably had light skin beneath hairy pelts. “If you shave a chimpanzee, its skin is light,” says evolutionary geneticist Sarah Tishkoff of the University of Pennsylvania, the lead author of the new study.

Is black skin dominant or recessive?

Inheritance of Skin Color Each gene has two forms: dark skin allele (A, B, and C) and light skin allele (a, b, and c). Neither allele is completely dominant to the other, and heterozygotes exhibit an intermediate phenotype (incomplete dominance).

When did skin color change?

All modern humans share a common ancestor who lived around 200,000 years ago in Africa. Comparisons between known skin pigmentation genes in chimpanzees and modern Africans show that dark skin evolved along with the loss of body hair about 1.2 million years ago and that this common ancestor had dark skin.

What skin color did the first humans have?

dark skin
These early humans probably had pale skin, much like humans’ closest living relative, the chimpanzee, which is white under its fur. Around 1.2 million to 1.8 million years ago, early Homo sapiens evolved dark skin.

Why is skin color dark in areas with high UV radiation?

As explained in Question 9, in high-UV environments, darker skin offers protection from the damaging effects of UV radiation, especially on DNA and the valuable nutrient folate. Thus, people with dark skin in these high-UV environments would have had an advantage in survival and reproduction.

Why do indigenous peoples in Africa have different skin colors?

Human skin color found in indigenous peoples varies with latitude. (Credit: Emmanuelle Bournay, UNEP/GRID-Arendal) But the human lineage did not remain exclusively in equatorial Africa. At different times, people ventured both north and south, to higher latitudes with less sunlight. That’s when vitamin D became a problem.

How did humans evolve their skin colors?

Members of the Hamer Tribe walk at sunset in Ethiopia’s Omo River valley. Studies show that new skin colors evolved as humans moved north and south from equatorial Africa toward higher latitudes. (Credit: Kimberly Petts/Shutterstock)

Where do most African Americans come from?

Blacks occupied the largest area, from the southern Sahara to most of sub-Saharan Africa. The ancestors of most African Americans came from Africa’s western coastal zone, but similar peoples occupied East Africa as well, north to the Sudan and south to the southeast coast of South Africa.

Why does human skin color vary from light to dark?

Human skin color reflects an evolutionary balancing act tens of thousands of years in the making. There’s a convincing explanation for why human skin tone varies as a global gradient, with the darkest populations around the equator and the lightest ones near the poles.