Change Is Coming – Lessons from Geology on Extinction Events

I’ve been reading the second edition of Michael Benton’s, When Life Nearly Died: The Greatest Mass Extinction of All Time, which tells of what we know of the Permian extinction prior to the rise of the dinosaurs.

Unlike the Cretaceous extinction that spelled doom for the dinosaurs (with a few bird-like exceptions), the Permian extinction killed off 90% of life on earth. It’s the most devastating extinction to date and one which our ancestry almost didn’t live through.

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When discussing the Permian extinction and the history of its discovery, one has to inevitably talk about some of the great English and French natural philosophers of the late Georgian and Victorian eras in order to understand why evidence for the Permian extinction was known but remained unrecognized well into the late 20th century.

Many natural philosophers of the late Georgian period were Christian, and while they didn’t generally hold to a literal interpretation of the Biblical, Genesis, they did nevertheless presume that a great flood had occurred that would have left evidence of massive death in the fossil record.

One such diluvialist was the French scientist, George Cuvier. Cuvier was an exceptional anatomist and was essentially the inventor of what we now know as Comparative Anatomy– which is the study of physical similarities and differences across species.

georges-cuvier.jpg

The French naturalist, Georges Cuvier (1769-1832).

In part because of his belief in the great flood, Cuvier was a proponent of Catastrophism, which is the theory that geological change is not gradual but has occurred in catastrophic sputters and spurts throughout historical time.

It was apparent to the English geologist, Charles Lyell, however, that there was evidence in the geologic record that earth’s revolutions can and do occur in a gradual manner as well. Lyell observed, for instance, on a tour of Italy that the ruins of the Temple of Serapis provided a perfect example of exactly this. Originally, the temple had been constructed during the age of the Roman Empire but had over time sunk below sea level, only to later rise above it again. In Lyell’s age, the tops of the pillar ruins showed dark rings, which were evidence of mollusk holes and the slow upheaval of geologic change. He provided an image of the ruins in his Principles.

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The ruins of the Temple of Serapis.

Lyell’s theory was known as Uniformitarianism and, according to Benton, proposed several things (p. 64):

  1. The laws of nature are constant throughout time.
  2. Scientists should use observations of modern phenomena to interpret the past.
  3. Processes in the past occurred at the same rate they do today. (This precludes the use of major catastrophes to explain these phenomena.)
  4. Geologic change occurs cyclically rather than linearly, which is known as “nonprogressionism.”

The first two of Lyell’s ideas about uniformity are sound ones that all scientists today should agree with. The latter two, however, were Lyellian assumptions, namely that cataclysmic events could not be used to explain geologic change and that, essentially, there was no progression of history but it was instead cyclical. (Both Lyell and Cuvier didn’t believe in the extinction of entire species but believed instead in their constancy as an ordained creation of God.)

Although Cuvier was incorrect that all geological change is the result of catastrophes, we now know that Lyell was equally as incorrect in presuming that catastrophes never occurred to effect the course of life on earth.

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The geologist, Charles Lyell (1797-1875).

Unfortunately, Lyell’s Principles was far more influential to the field of Geology than was Cuvier’s work. This was in part due to European and British perceptions of the French Revolution and especially of the Reign of Terror, after which many “French” ideas were deemed revolutionary and potentially dangerous. Therefore, while Catastrophism became known as decidedly French, Uniformitarianism was inherently English and “sensible”.

According to the author, Michael Benton, even during his training in the 1970s, geologic hypotheses invoking major catastrophes were thoroughly frowned upon and it wasn’t until a decade later that slowly scientists began to accept evidence that major extinction events have occurred in earth’s history that have severely impacted life on earth. There has been only a single massive extinction, the Permian, but there have been several intermediate extinctions, including the Cretaceous that led to the rise of mammals, and there have been many small extinctions littering our historical past (and, undoubtedly, our future).

So, as Cuvier would have it, geological evolution does indeed occur in sputters and spurts, yet it also occurs in a gradual, uniform Lyellian way. Both men were partly right even though history has remembered Lyell more kindly.

Of relevance to our own fates, geological knowledge gives us the foresight to understand that the recent human past has been blessed by a time of relative geological and climate quiet. However, in spite of how much we may fear to admit it, catastrophic change is inevitable and part of the rich and turbulent history of life on earth. While we shouldn’t work to usher such change in any sooner than need be, we must also admit to ourselves that it is coming.

12 responses to “Change Is Coming – Lessons from Geology on Extinction Events

  1. Stephan J Gould also proposed his theory of punctuated equilibrium. Evolutionary change occurs with slow changes over time punctuated by short periods of sudden and dramatic change. One of the new findings in autism is the high rates of de novo genetic changes found in autism. All males and all females generate egg or sperm mutations throughout their lives and the question seldom being asked is ‘where do they come from’. For example:

    http://www.ncbi.nlm.nih.gov/pubmed/20931230

    • Yes, I myself was thinking of the analogy between gradualism vs. punctuated equilibrium, Robert. (Ironically, the book, Puncuated Equilibrium, which is now a stand-alone taken from Gould’s tome, The Structure of Evolutionary Theory, is next on my to-read list. I have a genetics project in mind which may have some explanatory power for PE.) That’s an interesting article you link to; interindividual differences that could also be explanatory in types of cancer risk too I’d imagine. Although in terms of de novo mutations in autism, I’d think some of it is probably also linked with paternal age. But definitely differences across haplotypes are probable factors as well.

      • You might consider reading Ni Dieu, ni gène (Sonigo & Kupiec) in tandem with Gould’s “PE”. The theses are complementary.
        ——–

        The interesting history you highlight here is a good example of how brilliant insights often come mixed with and hindered by other mistaken beliefs which are held from stubborn and unwarranted prejudices–which finally cede their places only after their last supports are demolished by the facts within the valid part of the insights. Thus, to our view, it seems remarkable that gradual change and catastrophic upheaval could ever have been thought of as other than completely compatible ways to view a changing natural environment.

        In Paris, rue Cuvier runs not that far from the Gare Austerlitz and the great museum of natural history. I passed it so often on my way to the university library of the Université de Paris VII-Diderot, where, among the works on biological science s are the complete works of Darwin, standing there like majestic jewels, usually undisturbed.

      • Great to see you back at SoaC, proximity. 🙂 Yes, I absolutely love the history of science in Paris. Although admittedly I’ve read far more surrounding England’s scientific history. I just ordered and received (though haven’t begun to read) the book, “No Need for Geniuses” focusing on science in France peri- and post-Enlightenment. Re “Neither God Nor Gene”, do you have a good English translation of Sonigo and Kupiec’s work?

  2. The Earth breathes, but, occasionally, sneezes. 😉

    Pops

    Armed and Safe – not just a theory.

  3. I ALWAYS look in and read here even if I don’t comment. Yours is the Best Science Site on the Inter-Webs. With a “nearby site” in close second place. ;^)

    RE: Re “Neither God Nor Gene”, do you have a good English translation of Sonigo and Kupiec’s work?

    Hélas, Non.

    At this writing, there’s no translation I know of in English (though I haven’t looked lately.) That would require a little “push” from the professional side of the amphitheatre of science. I don’t think my recommendation would mean much to a science publisher.

    Meanwhile, there’s always TEAM “You, a good French-English dictionary, some patience– occasional breaks for wine and cheese — a little time and “Voilà!”– you’re reading and getting the gist of it like it was a strip of DNA bands.

    P.
    ————-

    (“Bernie for ‘Prez’ “)

    • LOL, love it. However, you seem to have a great handle on the language with familiarity with the original text. Perhaps that could be your own labor of love in future?

      • As a non-expert, I’d need to be able to consult at least one of the authors to clarify frequent questions on details. Without that, I couldn’t dream of trying to do a worthy translation. Then, there’s the probability that one or both of them are as proficient in English as I am in French. I think that Kupiec read Darwin in English. Maybe Sonigo did, too.

        Their work is important. It deserves a well-done translation.

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