One important fossil and two stories about fossils were announced this week. They demonstrate that the fossils themselves mean nothing apart from an interpretive context.
Birds: A new fossil of Archaeopteryx, the 11th known, has been discovered in Germany. This one shows many of the same fine details of other specimens, including detailed feathers, but lacks a head. New Scientist posted a good photo of it. Historians of science know that the interpretation of this fossil has undergone numerous swings since the time of Darwin, from transitional form, to full bird, to fake, and back to transitional form, according to the current leading consensus. No saying what the consensus in 2020 will be.
Cycads are an exotic kind of plant that look like palm trees but are gymnosperms, not angiosperms. Slow-growing and endangered, they have been known from Jurassic fossils and have been called classic “living fossils” due to their resemblance to living cycads. Time to revise the textbooks: PhysOrg reported, “Long-held belief debunked: Cycad is not a ‘Dinosaur Plant’.” Based on molecular studies (not fossils), researchers at the Royal Botanic Garden in Sydney have decided that modern cycads are “totally different,” having diversified within the last 10 million years. Some questions arise from this opinion, however. They are cycads, so they can’t be totally different from the Jurassic fossils in every sense. Further, the authors posit “a gap of 55 million years between when dinosaurs were extinct and modern cycads started to diversify,” an odd and seemingly ad hoc evolutionary move. (Note: the “molecular clock hypothesis” on which their analysis was based assumes a uniform rate of evolution.)
Even more questions arise from their explanation of why, after 55 million years of stasis, the cycads “began to diversify at the same time.” What could have triggered them to awaken from their long Darwinian slumber? “It seems that the trigger was a change in the climate, that is when global cooling began and when the world started having distinct seasons.” But if that is the case, it will now be necessary to explain why all the other species in the world followed other evolutionary trajectories, in spite of living on the same planet with the same climate history. Even more surprising is how the researchers could blame humans for endangering them, if they indeed had already survived 200 million years of every imaginable kind of global upheaval….
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