The Precarious Perch of Humans on the Tree of Life

How do anthropologists deduce human behavior from fossil remains? What is the connection between mitochondrial DNA and Eve? What can we learn about ourselves by studying other primates? What is our place on the “Tree of Life”? Can evolutionary biology explain complex modern human behavior?

Programs at many universities are trying to answer these and similar questions. Evolutionary anthropology is a multi-disciplinary field which investigates the history of humankind with the help of comparative analyses for genes, cultures, cognitive abilities, languages, and social systems. This includes not only past and present human populations, but also those of other primates.

In this field of study, human history is seen through the lens of modern evolutionary theory, building on Charles Darwin’s work, but transcending it. In 1859, Darwin drew on the best science available to elucidate four principles of evolution:
1. Adaptation. All organisms adapt to their environments.
2. Variation. Organisms tend to diversify.
3. Over-reproduction. Populations tend to reproduce beyond the environment’s ability to support them.
4. Natural selection determines greater or lesser reproductive success and species survival.

Modern evolutionary theory includes the concept of “descent with modification” at the level of genes, phenotypes and populations. Its two primary tenets are:
1. All living things are related to one another through common ancestors. Ultimately, all life forms flow from a single common ancestor.

2. New species originate from random genetic mutations. Some are more likely to persist and spread in the gene pool than others. (It is estimated that 99 per cent of species that have evolved are now extinct.)

The classical philosophical questions, “Who are we?” “How did we get here?” and “Why are we the way we are?” are addressed scientifically through the study of human and primate genetics, behavior, culture and technology. This draws on the resources of fields such as archeology, behavioral ecology, comparative psychology, linguistics, and microbiology.

The Evolutionary Anthropology Society (EAS) brings together “all those interested in applying modern evolutionary theory to the analysis of human biology, behavior, and culture.” One of its primary purposes is “to promote the application of modern evolutionary theory to the analysis of human behavior and culture (including its paleontological, archaeological, and linguistic manifestations).”

This field of study draws together the physical and social sciences, considering both genetic and environmental influences. It is threatening to those who wish to give humankind a special status, one step up the ladder from the so-called animal kingdom. If it turns out that humans are descended from a single ancestor, they will have to choose between seeing themselves as “just another animal”, or promoting animals to living beings who have a intrinsic value beyond their usefulness to humans.
Evolutionary Anthropology Society (EAS)
Max Plank Institute of Evolutionary Anthropology
Wikipedia entry
Modern theory of evolution