Searching for the evolutionary roots of human morality

Humans, like all other organisms, have an evolutionary history, and many important events in our history have been documented by paleontologists who study the fossil record, and by molecular geneticists who sequence our genes. The challenge faced by researchers studying the evolutionary origins of morality is that behavior and cognition do not leave traces in the fossil record and cannot be extracted from DNA. However, we can gain some understanding of the evolutionary roots of morality by comparing ourselves to other closely related organisms. Evolutionary biologists generally reason that if two closely related species share a particular trait, then it is likely that they inherited the trait from their most recent common ancestor. Thus, if humans share a characteristic with chimpanzees (Pan troglodytes), such as the absence of a tail, then it is likely that the same trait characterized our most recent common ancestor, which lived about 5-7 million years ago. On the other hand, if humans possess a trait, such as bipedalism, which chimpanzees and other great apes do not display, we can be reasonably confident that this trait evolved after the human and chimpanzee lineages diverged.