How Fossils Overturned Evolution
Walcott conservatively tried to place the creatures into groups that were known from other fossils, or living descendants. But decades later, when the Cambridge geologist Harry Whittington and his colleagues took another look, they realized that the Burgess Shale contained not just unique species, but entire phyla the broadest classification of animals new to science. The first European to see a kangaroo could not have been more surprised. What made the creatures seem new is they have no living descendants.
They represent entire lineages, major branches on the tree of life, left behind by evolution, most likely in one of the mass extinctions that punctuate the natural history of this planet. Other lineages did survive, including that of the humble Pikaia , which qualifies as at least a collateral ancestor of the vertebrates, including us. And that raises the profound, almost beautiful mystery that Gould saw in the Burgess Shale, the subject of his book Wonderful Life : Why us?
If one could somehow turn the clock back to the Cambrian and run the game again, there is no reason to think the outcome would be the same. These little creatures, entombed in rock for a half-billion years, are a reminder that we are so very lucky to be here. A science writer and author of the book High Rise , Jerry Adler is a frequent contributor to Smithsonian. He wrote about the role of fire in shaping human evolution in our June issue.
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The biologist using insect eggs to overturn evolutionary doctrine
Ask Smithsonian. The several different Neanderthal nuclear-DNA genomes now available have been extracted from bones several tens of thousands of years apart, to give genomics a whole new dimension—time. More startling still, genomes have been extracted from unremarkable bones, otherwise not attributable to species, but which have rocked our understanding of human evolution. From a cave in southern Siberia came a tiny finger bone, no bigger than a grain of rice, yielding a genome of a completely unknown human species, known as the Denisovans. These were neither Neanderthals nor modern humans, but related to both.
They lived in eastern Asia until as recently as 30, years ago, but before their genome had been discovered, nobody had any idea that they existed.
Cleveland researchers say fossil find overturns thinking on human evolution - dispohandcoligh.tk
Do these represent hitherto unknown species, rather than deformed examples of species we know? Could some puzzling skulls from China represent Denisovans, or other, even more shadowy species? Some modern African genomes show traces of some non-human archaic past: might this have some connection with two peculiar skulls from Iwo Eleru in Nigeria—dated to approximately 13, b. Still commonly perceived as an orderly progression from primitive to advanced, human evolution is actually far more complicated, as genomics studies have already demonstrated.
Vociferously dismissed by many as a pathological modern human, it is now as certain as anything can be in science that it represents a relic of a phase of human evolution that had hitherto been completely unknown, even unsuspected. Now, given that the chances of any creature becoming a fossil are exceedingly remote, you have to ask yourself the following question: If the Hobbit were the only hitherto unknown, enigmatic fossil human that ever existed, how likely do you think it is that a group of researchers, who were, incidentally, looking for something else, just happened to have stumbled on it, in just this one cave, in an archipelago full of similar deep, unexplored caves?
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To be sure, someone has to win the lottery. The DNA from Denisova, and the hints from genomes of the existence of further, undiscovered, archaic forms, supports that view. Because we H. Creation myths including the one in the Bible have humans created in their modern forms, without antecedents. When evolution came along, a misreading of natural selection as a kind of progressive force for improvement the result of a bastard fusion of Darwinism with older currents of thought gave us a single line of ancestors which were presumably there in the rocks for us to find, if we knew where to look, whose evolution would naturally lead to our current exalted state, higher than apes, but beneath the angels.
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The current evidence, from fossils and lately from DNA, reveals a very different picture. There have been humans of various sorts scattered across the world for millions of years. At first in Africa, where the human family appears to have evolved, but, some time around two million years ago, across the Old World. The human family has always been very thinly spread, separated into groups that are more or less genetically distinct, interacting and interbreeding only rarely.
If we wish to find a model for most of our existence, there is one—modern chimpanzees. There is more genetic diversity in the few scattered populations of chimps in West Africa than in the entirety of H. This speaks to another feature of our genetic past.
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