If there is no biological explanation for race, how did it come about and why does it continue to be important to this day?

        People originated from Africa. Thousands of years ago, humans migrated from African to the rest of the world. Initially they went north towards Egypt to Saudi Arabia, across southern Asia and even further south to Australia. Another group went north to Egypt and made their way to Europe. A third group went across Russia and up through Alaska to North America. Finally, some from that group continued on to South America. Everyone that settled near the Equator (more or less between the Tropic of Cancer and the Tropic of Capricorn), had a darker skin color than those closer to both the North and South Poles. This is because some traits evolved by natural selection in order for people to adapt to different climates or environments. Being near the Equator is quite hot, so having darker skin might make a person less likely to get skin cancer from the ever-present sun. Someone who had migrated closer to the North and South Poles would not need something in their biological makeup that would prevent them from getting skin cancer. As the biological explanation is factually inaccurate, this geographical reason for races is necessary.
        Race also came about culturally despite a biological explanation, because two people of different "races" look very different. This could be based on skin color, nose and eye shape, height, etc. Europeans who discovered new lands were curious about these differences in the natives, and since they seemed to be living more primitively, didn't speak English (or whatever the language may have been), and had not been the ones to find the Europeans, the explorers presumed they were lesser beings. When it was realized that the natives were, in fact, humans as well, these stigmas remained because they were still visibly different.
        The reason race is still important today is because people still take notice of it. Race is one of the first thing a person notices about another person. People still regularly try to fit in with "their own kind," and people still have common misconceptions about skin color and "race." Even though the Declaration of Independence in 1776 declared that "All men are created equal," many people don't believe it. Besides, when the few men who got together wrote this, they 1) neglected to include women and 2) were really only thinking of white Europeans and not those of other races. Additionally, even though humans have left their initial homes from centuries ago, there are still few enough people in one area for that group to be considered a minority. Until, the world has become properly mixed thousands of years from now, if at all, meaning minority in the way we use it today will become an obsolete term as there will be a roughly the same number of all different "races"in any given place, racism won't be an issue. (This is not to say that racism would stop existing, but I think it would be more difficult to be racist in a place where everyone is different.)