Things sure have changed… GG Simpson & the “historian of life”

3 04 2007

Yesterday I received a yellowing copy of George Gaylord Simpson’s The Meaning of Evolution (3rd Edition, 1950), and although I am only about 50 pages into it, it is absolutely amazing how much things have changed in the last half century when it comes to evolution. In the book, Simpson notes that the oldest rocks we have are about 2,000,000,000 years old, there are about 1,000,000 extant species, there was some sort of extinction near the end-Permian (although it was largely a mystery), there were few fossils from before the Cambrian (although he rightly notes that the Cambrian “explosion” that creationists cite as proof against evolution is not true), and dinosaurs are still dragging their tails and looking more like big, grumpy lizards. Indeed, on page 30 there is a chart showing the radiation of “significant” phyla through time, Chordates seemingly more diverse than arthropods and even molluscs during the present, at least according to the chart. While Simpson notes that there are likely more arthropods than currently recognized, it is still interesting to consider that not long ago the whole of our understanding of life’s diversity didn’t even scratch the surface.

A piece from the Prologue is also interesting, not only because it notes the professional bias of the time, but because it perhaps reflects my own interest in paleontology & evolution in more “traditional” fields of study;

There are many ways of studying the history of life. The geneticist, raising tiny fruit flies in bottles, and the well driller, piercing thousands of feet of the earth’s crust in search of oil, are both contributing to this study. One way of pursuing the study, the most direct way and the one around which all other contributions need to be organized to articulate the whole history, is that of the paleontologist. In his most immediate and narrow occupation, the paleontologist is a student of fossils, the preserved remains of ancient life. He seeks these in the rocks throughout all the lands of the earth, takes them to his laboratory, cleans them for study, compares them with each other, identifies and names their kinds, determines their ages, and finally sets up their associations and historical sequences. As with any other sort of worker, the paleontologist’s day-by-day attention is mostly focused on the concrete and more or less routine details of the jab in hand rather than on the broad whole of which this job is a small part. When he does turn to these broader aspects, the paleontologist becomes not merely a student of fossils but a historian of life. The historian of life takes not only knowledge of fossils but also a tremendous array of pertinent facts from other fields of earth sciences and of life sciences and weaves them all into an integral interpretation of what the world of life is like and how it came to be so. Finally, he is bound to reflect still more deeply and to face the riddles of the meaning and nature of life and of man as well as problems of human values and conduct. The history of life certainly bears directly on all these riddles and problems, and realization of its own value demands investigation of this bearing.

Sounds awfully lofty, doesn’t it? I especially find this passage interesting in that over the past week, science bloggers have been abuzz about a new study that used genetic data to try and determine what happened in mammalian evolution, the science of genetics having considerably more reach and power than it did in Simpson’s time. As a child, however, I didn’t grow up knowing anything about genetics; if you wanted to understand evolution and life’s history, paleontology is the way to go. Indeed, it is clear that in Simpson’s writing that while he does not write genetics off as unimportant, it only merely contributes to understanding gained from paleontology, the field which allows for scientific and well as (according to the last few sentences, at least) philosophical understanding of life and its history. I wonder what Simpson would say today, with genetic studies and paleontology-based studies sometimes at odds with each other, many people choosing one over the other. As with the new mammal diversification study, many of those who work in genetics and related fields heralded it as doing away with an old paradigm, whereas others (like myself) believed that it was a bit over-hyped and did not say what many ascribed to it (that there was no mammal proliferation following the K/T extinction). Hopefully, paleontologists and geneticists will work together in the future to help our understanding of evolution and extinction, but for my own part I still largely fall into the paleontology camp; I grew up wanting to be the “historian of life” that Simpson writes of.

I know that if I am ever to truly understand evolution, I cannot overlook genetics or developmental studies; ecology, paleontology, anatomy, etc. do not in of themselves constitute the whole picture. There is something that I find enthralling about bushwhacking through the forest in order to get a better idea of the life history of an organism, or peeling away layers of rock to reveal an organism that once was alive and has a story of its own to tell. There must be a psychological component (likely Jungian) to my love for these outdoor studies of the individual or population and my aversion to laboratory work, which I sometimes think of as sterile and boring. This is not to say that I find such work unimportant, but rather that I am not cut out to do it and I must overcome my own bias. If I cannot, if I simply regard my own narrow field as work as the field that illuminates science, I will be doing a disservice to myself and those who may agree with me.




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