To Be Human: Genetics, Origins, and Identity
What does it mean to be human? We often strive to understand our uniqueness in this world by evaluating differences between ourselves and other living organisms. In this film, Drs. Georgia M. Dunston, Frans De Waal, and Rick Potts take a different approach, observing the similarities that exist between species and considering who we are in light of common ancestry and advances in genetics, primatology, and anthropology. They explain how new discoveries allow us to piece together a greater understanding of who we are as humans.
Dr. Frans de Waal is the Charles Howard Candler professor of primate behavior in the Emory University psychology department in Atlanta, Georgia, and director of the Living Links Center at the Yerkes National Primate Research Center.
Dr. Georgia Dunston is the chair of the Department of Microbiology and the founding director of the National Human Genome Center (NHGC) at Howard University.
Dr. Richard B. Potts is a paleoanthropologist and the director of the Smithsonian Institution Museum of Natural History’s Human Origins Program. Prior to joining the Smithsonian Institution, he taught at Yale University and was its Peabody Museum of Natural History Curator of Physical Anthropology. He has been involved with early human excavation sites in Africa and Asia.
Dr. Rick Potts: All species are unique in some way and humans happen to be unique also and we have a special interest in our own uniqueness.
Dr. Frans de Waal: Face recognition used to be thought of as uniquely human, but all the primates at the time had been tested on human pictures and they were not good at human pictures. Until we started testing chimpanzees on chimpanzee pictures. You can show them a model on a touch screen, and then you show two young chimpanzees and they can pick out who the offspring of the mother is and so on. And then it was found in the monkeys, then it was found in sheep, and now there’s a study on wasps. And so, this is one of those typical stories is that we first think that it is uniquely human and then it spreads and we find that it’s actually in many corners of the animal kingdom.
Dr. Georgia Dunston: So, to know what it is to be human, you have to get outside of the boundaries of humans so you can challenge our view, not only of biology, but of our identity.
Dr. Frans de Waal: The human species has such a tendency to set itself apart from the animal kingdom, but all sorts of animals come in who can do things that we thought were uniquely human. We usually find it first in the apes because we recognize it most easily, but then after the apes, come the monkeys and the dogs and the dolphins and the corvids. Corvids have very large brains relative to their bodies, and we have now discovered that not only do they use tools – we knew that, I believe – but they make tools. They pick up a little branch or a little leaf, and they start modifying it until it becomes a little hook so that they can stick it into the crevice and extract food. So that was one of the things that was claimed to be uniquely human and now we know that the corvids do the same thing. Recently, we have found that fifty genes that relate to articulation of sounds, which we use for speech, can be found in songbirds as well. So we always find these connections and human language is unique, but it’s never 100 percent, that’s an impossibility.
Dr. Rick Potts: Humans are primates, which includes the lemurs, monkeys, apes, and us. We owe a lot of our unique qualities as matters of difference in extent from other primates rather than differences of kind.
Dr. Frans de Waal: So, for example, human morality certainly is not something we developed from scratch. If you look at what I call the building blocks, which for me are empathy, being interested in others, and reciprocity, setting up a cooperative structure in which you help each other. If those are the building blocks, we can find those building blocks in other species. For example, chimpanzees console others who are distressed. If someone has been defeated in a fight, they go over and embrace them and groom them, and so on. If you break morality down into parts, you’re going to find some of these parts in other species. Whether other species have the whole thing that we call human morality, that’s a different issue.
Dr. Rick Potts: The nature of becoming human has been a piecing together of qualities that define ourselves as distinct from all other creatures. We walk upright, the size of our brains, our dependence on technology and especially symbolism. We live in a symbolic universe and we build different ones of those which we call cultures. Well, when did we become human? Human beings evolved on a very, very dynamic and changeable planet. Our evolutionary tree, in fact. At least 18 different species of different lineages that belong in our own evolutionary tree. All of those other ways of life have become extinct, and there’s only one of us now. I often say it as “the last biped standing.”
The skulls that I have here – this particular one is Homo habilis, and the name habilis comes from the idea of handy man. It was known to have made early stone tools. The idea that we could have access to such rich plant and animal material was critical to the initial increase in brain size that ultimately led to a brain size as large as this one – Homo heidelbergensis. Later on, of course, giving rise to Homo sapiens, and you can see again the evolution of a much larger brain, a projecting nose, and so that projecting nose was important in being able to humidify air as it’s breathed in and not lose that humidity when it’s breathed out. So, in many ways, the answer to what it means to be human is that part of what it means to be human has been a process of becoming human, a history that goes back 6 million years.
Dr. Georgia Dunston: The genome story says human origins are in Africa. Looking at the relationships of sequence, the genome bears out that literally we are one brotherhood, a sisterhood. Genetics is the study of individual genes or collections of genes. The human genome, we’re looking at all of the genes working together as one. The genome is that part that allows us to determine how we survive in different environments. For example, skin color. We know from anthropology studies, from archaeology studies that humans moved out to another environment, whether it’s far-east Asia, whether it’s Western Europe.
Where the Sun’s rays were not as intense, the loss of skin color had an advantage in being able to survive in certain environments. The genome had to adapt to whatever environment. The amount of information to account for anatomical features, skin color, hair texture, all of the things that we use, that we see on the outside, takes less than one tenth of one percent of our total genome information. But they are the things that allow us to distinguish ourselves, one from another. So, you can’t separate the role that the genome plays in our sense of identity.
Dr. Rick Potts: Embodied in Homo sapiens, human beings today, we have an amazing diversity within the one species of cultures, of ways of life, of ways of speaking and ways of assigning meaning. And so, what’s so interesting about human beings is this, in a sense, tension between the unity of our species, the long history that all human beings share over millions of years, plus the unity of the small amount of genetic diversity that exists, but then this outward expression that seems to divide people, they form the walls. But I think that what we need is this bring together, the unity and the diversity of human beings into a more holistic picture of who human beings are today.
- Course Categories: General Theology
- Science Topics: Life Sciences
genetics, Anthropology, science and religion, biology, To Be Human, common ancestry, becoming human, homo sapiens, Dr. Frans de Waal, Dr. Georgia Dunston, Dr. Richard B. Potts