This edition: Patterns of Variation
The lesson begins with comments on some instances of ethnic genocide that have occurred in the past in the Sudan, Rwanda, Bosnia, and Nazi Germany during World War II. It relates these occurrences to the concept of “race,” a concept based on physical differences between groups. It defines the everyday usage of the word “race” and includes its biological definition, which leads to the conclusion that the word and concept of “race” cannot apply to Homo sapiens because, as is well understood, there are no subspecies of Homo sapiens. The video then briefly explains the historical context of how the concept of race emerged among European explorers during the 16th century. It explains that today anthropologists and scholars look beyond visible physical differences to explain human variation. They analyze genetics and DNA, the cornerstone of genetic studies, to describe and understand human diversity. The lesson defines polymorphisms and clearly explains how their presence in human genotypes causes differences in phenotypic variation. Using interviews with a Somali family who had to flee their country because of race-based violence, the lesson points out that the easiest difference to see is skin color. The lesson explains that science now explains skin color shifts as a response to geographical regions called clines. A montage of images illustrates the phenotypic variation of skin tones in Africa to illustrate this perspective. The video features Gregory Lanzaro, a medical entomologist working to eradicate malaria, and it describes how the sickle-cell allele began and how it has become adaptive in malarial regions. The concept that humans are products of biocultural evolution is discussed, as well as the latest theoretical viewpoints on the “thrifty gene” hypothesis.