Darwin

An Evolution of Thinking

by Peter Ungar, Professor of Anthropology

This year marks the 150th anniversary of Charles Darwin’s seminal work The Origin of Species, and the 200th anniversary of his death. Darwin’s ideas remain today fundamental guiding principles for research in many of the disciplines represented in the Fulbright College of Arts and Sciences. But the name “Darwin” strikes fear in the hearts of many of our students, especially those not exposed to evolutionary theory before they arrive in our hallowed classroms. Darwin’s ideas are really not scary — they are simple, obvious, and elegant.

So what, after all is evolution, and how did Darwin contribute to our understanding of it? Evolution can be defined as a change between generations in frequencies with which inherited traits appear in a population. Enough change over enough generations, and you get a new species. If, for example, the percentage of people with “dimples” (or some other trait) changes over time, evolution has occurred. It’s really that simple. Trait frequencies can change between generations for many reasons. Perhaps a population bottleneck leaves the next generation with a disproportionate number of people with dimples, or maybe legions of dimple-less people migrate in or out of the population.

The principal driving force of evolution though, is Natural Selection. And we can credit Charles Darwin, along with Alfred Wallace, for its discovery. The basic idea is that individuals within a species vary, and that variation can be passed between generations. Those with favorable traits will survive longer and produce more offspring that those with less favorable ones. Over time, species will evolve traits to improve their “fit” in a given environment. This may seem simple and intuitive, but it remains the foundation of the most profound law in all of biology, and it explains the diversity of life on this planet and its likely descent from a single common ancestor.

But if Natural Selection is so obvious to us today, why didn’t Aristotle or any of the countless naturalists in the two millennia that followed him think of it? Aristotle believed that biological species were real and unchanging entities with fundamental “essences”, and that variation between individuals was simply imperfection in translation to the world around us. The brilliance of Darwin (and Wallace) was not the idea of natural selection per se, but rather, the rejection of long-held notions of essentialism, and the recognition that variation was not imperfection, but the key to unlocking the fundamental organizing principle of all living things on Earth.

From an anthropological perspective, the history of evolutionary theory has been largely about the human struggle to come to terms with our place in Nature. Darwin and his followers recognized that we humans are simply one small branch on the tree of life. We are not apart from nature, but a part of it. This can be a hard pill to swallow for some. In fact, the struggle continues today, 150 years after The Origin of Species was published, played out in school board meetings and courtrooms across the country.

Nonetheless, as the great 20th century geneticist Theodosius Dobzhansky wrote, “nothing in biology makes sense except in the light of evolution”. Evolution happens; it is fact. But the devil is in the details, and students and faculty here in Fulbright College are helping to improve our understanding of the origin and evolution of life, and of our place in Nature.

Seemingly uncountable numbers of researchers dedicate their lives to teasing more and more of the details that explain how living things on this planet came to be as they are today. In my own field of research, paleoanthropology, new technologies are giving us details about human evolution that Darwin could not have possibly imagined. Advances in the study of ancient DNA, for example, hint the colors of the hair and skin of Neandertals, and high-resolution imaging of microscopic tooth wear combined with isotopic signatures of dental tissues offer up menus for the last suppers of our fossil forebearers.

New methods and theories in anthropology, evolutionary and developmental biology, and a whole host of other fields continue to bring new insights, and allow us to expand the boundaries of our knowledge, and even what is “knowable”. Nature does not give up its secrets easily, but the study of evolution is itself evolving, and faculty and staff here at the University of Arkansas and on other campuses around the world are training the next generation of researchers to meet this challenge. We can no more predict what we will learn about evolution than we can predict what evolution itself will bring. Nevertheless, just as life itself will continue to evolve, so too will our understanding of how life came to be the way it is today.

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