I heard somewhere that Neo-Darwinism has been set aside by evolutionary biologists at this point…which I assume is the idea of gradualistic evolution championed by Ernst Mayr et alia as Population genetics and other fields were unified with natural selection theory. Is this setting aside true?
If so what new theories have taken its place?
Thanks.
Also wanted to say thanks for the reflections on the issues of “delusion”, mental illness, and religious fervor.
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Excellent question, and I look forward for the real scientists to answer, though my impression is that like all theories, evulutionary thought changes and develops as better information comes about, which is a good thing. As I understand it the " modern synthesis"which built on Darwinism and which has been around 75 or so years, is being built on by adding more factors in what is called the “extended evolutionary synthesis” with some healthy debate, but it is not a defeat of the old theory, but an…evolution. Extended evolutionary synthesis - Wikipedia
To quote from the Wikipedia article:
The biologist Eugene Koonin wrote in 2009 that “the new developments in evolutionary biology by no account should be viewed as refutation of Darwin. On the contrary, they are widening the trails that Darwin blazed 150 years ago and reveal the extraordinary fertility of his thinking.”
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I believe the typical scientist response is that Neo-Darwinism has been dead for decades and newer models take into account the important role of neutral drift and horizontal gene transfer. (What that means, I’m not all that sure, but that is the refrain I have heard around here.)
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What, exactly, does one mean by “neo-Darwinism” anyway?
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They’ll say that, or they’ll say that Neo-Darwinism has been expanded to include those newer processes. It’s a meaningless distinction, of course. Other features of classical neo-Darwinism that have been left behind, at least to some extent: the assumption that phenotypic variation can occur in any direction, rather than being highly constrained by existing developmental pathways; that adaptive evolution occurs by numerous small changes, rather than by something like polyploidization, which can cause dramatic changes in a single generation; that selection operates on a pool of phenotypic variation, rather than sometimes being rate limited by the arrival of certain mutations.
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The only part of Neo-Darwinism that’s “dead” is the idea, (probably never held by evolutionary biologists), that evolutionary theory was complete. This idea was promoted to some extent, probably unintentionally, by some of the popular press and writings of science communicators like Dawkins. The reality is of course, that nothing in biology is complete, we have a long way to go in all fields, and evolutionary theory is certainly among them. To continue with @glipsnort’s comments, we have new understanding of the environmental feedback systems in niche construction, mechanisms (which Steve mentioned) for Gould’s observations of punctuated equilibrium, the role of robustness in protein function in allowing for the rise of new functional variants (A. Wagner’s work), and the very complex effects of gene regulatory network alterations on evolution.
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Is Neo-Darwinism passe? No, in the sense that many scientists still believe in it, but it should be.
What is Neo-Darwinism? One source cited said it was a combination of Survival of the fittest Natural Selection, Genetic Variation, and Mendelian Inheritance, which seems a fair description. Also I would say that it is defined by Dawkins and Co. as the Selfish Gene.
The problem with Neo-Darwinism or the Modern Synthesis is that6 its focus is almost entirely on Genes and genetic changes and not upon the ecology or climate change which drives genetic change.
The mammals did not drive the dinosaurs to extinction, climate change did. Natural Selection is not powered by conflict within species, but by Symbiosis It is only recently that noted evolutionist, E. O. Wilson, has been able to combine evolution and ecology, and then to the objections of Dawkins.
The Extended Synthesis makes a move toward combining evolution and ecology, again with the opposition of Dawkins, but it seems to be limited. In my opinion the fact that Survival of the Fittest as Darwin understood it is no long a viable scientific idea, but must be replaced by ecology, means that Neo-Darwinism is passe, is out of date and no longer valid. It has nothing to do with ID which is the chimera of the evolution debate… .