“It turns out that everybody on Earth is descended from people that lived here in Africa,” Nye said in the TikTok clip, pointing to two maps highlighting the intensity of Earth’s ultraviolet rays as well as various skin shades around the globe.
“And then as groups of us moved around the world, the color of our skin had to change. And here’s why. Our skin is where we make vitamin D. If you don’t get enough ultraviolet, then you don’t get enough vitamin D. But if you get too much ultraviolet, then you break down your folates. You have to have it in perfect balance. And because the ultraviolet varies, the color of our skin varies. And that’s it, everybody. That’s why we have different colored skin.”
Nye went on to argue that humans were all the same species but weren’t “treating each other fairly.”
“Not everybody is getting an even shake,” he said, rattling a bottle of vitamin D. “So it’s time to change things.”
At the beginning of the video, Nye was referring to the work of Nina Jablonski and George Chaplin, two Penn State University anthropologists. They carried out extensive research on the link between skin color and ultraviolet radiation as it relates to the production of vitamin D, which they called a “selective force in the evolution of pigmentation” in a scientific paper published in 2010.
The Smithsonian National Museum of Natural History’s website on modern human diversity points out that because “strong sun exposure damages the body, the solution was to evolve skin that was permanently dark so as to protect against the sun’s more damaging rays.”
Nye’s video went viral on Twitter shortly after it was posted, with multiple commentators praising his usage of TikTok to share scientific knowledge. Others said that his argument that humans are all the same species proved the folly of racism.
Racism is “the belief that another person is less than human ... because of skin color, language, customs, place of birth or any factor that supposedly reveals the basic nature of that person,” according to the Anti-Defamation League.
Nye previously used TikTok to demonstrate the effectiveness of face masks against COVID-19, arguing that wearing a mask is “literally a matter of life and death.”