Hat tip to the AfroSpear's All About Race Blog.
The concept of “race” may be the most powerful social construct ever created. This link takes you to a PBS site that lays out “Ten Quick Facts about 'Race'.” Some highlights:
"Race" is a modern idea - Ancient societies did not divide people according to physical differences, but according to religion, status, class, even language.
Race and freedom were born together - When the US was founded, equality was a radical new idea. But our early economy was based largely on slavery. The concept of race helped to explain why some people could be denied the rights and freedoms that others took for granted.
Race Justified social inequalities as natural - As the race concept evolved, it justified extermination of Native Americans, exclusion of Asian immigrants, and taking of Mexican lands. Racial practices were institutionalized within government, laws and society.
Skin color is only skin deep - Most traits are inherited independently of one another. The genes for skin color have nothing to do with genes for hair texture, eye shape, blood type, musical talent or athletic ability.
Race is not biological but racism is still real - "Race" is still a powerful social idea that gives different people different access to opportunities and resources. Our government and society have created advantages to being white. This affects everyone, whether we are aware of it or not. Ten Quick Facts about Race, PBS
Also, check out “The 'Race' Timeline”which answers the question: Has "race" always been the same?