From the University of Glasgow. A friend draws our attention to these words in a recent open-access paper: “Although biologists are now moving beyond the idea that random mutation provides the sole source of variation for adaptive evolution, we still assume that variation occurs randomly…” in the Abstract.
Later: “Darwin’s idea that variation is generated randomly has largely been taken for granted rather than tested, representing a fundamental gap in our understanding of evolution.”
They propose “nonrandom variation”:
Abstract: The generation of variation is paramount for the action of natural selection. Although biologists are now moving beyond the idea that random mutation provides the sole source of variation for adaptive evolution, we still assume that variation occurs randomly. In this review, we discuss an alternative view for how phenotypic plasticity, which has become well accepted as a source of phenotypic variation within evolutionary biology, can generate nonrandom variation. Although phenotypic plasticity is often defined as a property of a genotype, we argue that it needs to be considered more explicitly as a property of developmental systems involving more than the genotype. We provide examples of where plasticity could be initiating developmental bias, either through direct active responses to similar stimuli across populations or as the result of programmed variation within developmental systems. Such biased variation can echo past adaptations that reflect the evolutionary history of a lineage but can also serve to initiate evolution when environments change. Such adaptive programs can remain latent for millions of years and allow development to harbor an array of complex adaptations that can initiate new bouts of evolution. Specifically, we address how ideas such as the flexible stem hypothesis and cryptic genetic variation overlap, how modularity among traits can direct the outcomes of plasticity, and how the structure of developmental signaling pathways is limited to a few outcomes. We highlight key questions throughout and conclude by providing suggestions for future research that can address how plasticity initiates and harbors developmental bias. pdf.(open access) – Does phenotypic plasticity initiate developmental bias? Kevin J. Parsons Kirsty McWhinnie Natalie Pilakouta Lynsey Walker Evolution & Development First published: 26 July 2019 https://doi.org/10.1111/ede.12304 More.
Perhaps the researchers will help elucidate some laws that govern development over time.
Darwin, our friend notes, felt much more strongly about the importance of randomness, as he told Lyell: “If I were convinced that I required such additions to the theory of natural selection, I would reject it as rubbish.” (To Charles Lyell 11 October )
See also: So creationism works—but only for genes? So 2/3 of the time, we have “ de novo emergence from ancestral non-genic sequences, such that homologues genuinely do not exist?” Okay. Somebody better go put their arm around the Selfish Gene. It’s tough being the Last Darwinian.
Gene, we did not do this to you. Francis Collins and Craig Venter did this to you. Honest.
Direct experimental falsification of Darwinism? (The Selfish Gene was heard to sob uncontrollably in the background.)
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