life sciences
"In the strait of Magellan, looking due southward from Port Famine, the distant channels between the mountains appeared from their gloominess to lead beyond the confines of the world."
When Darwin composed this journal entry in Voyage of the Beagle, he had not yet read Lyell's Principles of Geology, which would give him a sense of the earth's antiquity and the incremental and relentless change that underlies his theory of evolution. Nor had he visited the Galapagos Islands, where he puzzled over forms of life that were both different from and similar to what he found on the South American mainland. Still, he somehow anticipated that he had already embarked upon a voyage leading beyond the familiar world, the world in which prevailing tenets of science held that nature is as it has always been. With the publication of Origin of Species, the moorings of humanity's self-understanding were loosed, and we have been journeying deeper into the uncanny ever since.
Darwin's account of evolution portrays life as a shape shifter, a restless and protean apparition that assumes myriad forms over vast stretches of time. Today, scientists tell us that the phenomenon of life is linked to the minuscule world of chemical happenings among nonliving molecules inhabiting every living cell. The intricate dance of those molecular entities is choreographed by laws elaborated by the physical and chemical sciences. When the whirl and joining of particles achieves a measure of complexity, an invisible threshold--dividing nonlife from life--is crossed. The three and a half billion-year history of life on earth, we now know, has been orchestrated by permutations of the molecule deoxyribonucleic acid--DNA. The substance of heredity, DNA's double helix stores and transmits vital biochemical information from generation to generation. Its coded instructions determine whether a developing embryo will grow into something with wings, fins, or opposable thumbs--perhaps with its mother's blue eyes or a predisposition that might lead to cancer.
Our understanding and increasing skill at manipulating the engine of life has set us on a course whose import is at once exhilarating and challenging. Biology professor Joe Ecker points out that databases being assembled by genome sequencing projects like the one he oversees are changing in fundamental ways how science is done. A whole industry has grown out of genetic research, and the effects are already being felt in medicine, pharmaceuticals, agriculture, law enforcement, and nutrition. Nancy Bonini of the Biology faculty has identified the molecular machinery that gives rise to certain neurodegenerative disorders, bringing closer the day when these diseases are no longer incurable.
Not long ago, Penn paleontologist Neil Shubin, along with Ted Daescher, Gr'98, unearthed a fossil fish with unusual finger-like appendages. The find behooves scientists to revise a chapter in our understanding of the fossil record, the story told in bones and rock impressions left behind by long vanished species. The chronicle etched in the fossil record confirms Darwin's thesis: Having bubbled up from the mud of a dead planet, life--the thing that lives amid the bones--ceaselessly sheds the skins of life forms as if to cast off death. In a moment of unscientific self-reflection, Shubin told ABC's Nightline, "It's like looking into a mirror that's 370 million years old and seeing part of my body in this fish." Like Darwin, he too senses the strangeness of it. We have come from a far place and find ourselves on a journey whose destination has not been disclosed.