Although we can't know precisely what is in the minds of other animals, scientists can make inferences through studies of animal behavior that inform our understanding. Humans have much in common with other mammals on Earth in terms of physiology but are most like two other living primate species in terms of genetics and morphology: the chimpanzee and bonobo, with whom we spent the most time on the phylogenetic tree. However, as much like the chimpanzee and bonobo as we are, the differences are vast.Īpart from our obvious intellectual capabilities that distinguish us as a species, humans have several unique physical, social, biological, and emotional traits. Although different branches of humans died out, the branch leading to the modern human, Homo sapiens, continued to evolve. These species, called hominins, migrated into Asia around 2 million years ago, then into Europe and the rest of the world much later.

Information obtained from early-human fossils and archaeological remains suggests that there were 15 to 20 different species of early humans several million years ago. Evolutionary biology and scientific evidence tell us that all humans evolved from apelike ancestors more than 6 million years ago in Africa. Most species that have existed on planet Earth are extinct, including a number of early human species. In fact, the very act of contemplating what makes us human is unique among animal species. While there may be no single conclusion, there is no doubt that humans are, indeed, unique. Ancient Greek philosophers Socrates, Plato, and Aristotle all theorized about the nature of human existence as have countless philosophers since. With the discovery of fossils and scientific evidence, scientists have developed theories as well.

The topic of human existence has been pondered for thousands of years. There are multiple theories about what makes us human-several that are related or interconnected.

What makes us who we are