Presentation on theme: "WAAS General Assembly Hyderabad, India October 17-19, 2008 Darwinism: Dead Wrong? Evolution ≠ Adaptation Writ Large Jeffrey H. Schwartz President, World."— Presentation transcript:
WAAS General Assembly Hyderabad, India October 17-19, 2008 Darwinism: Dead Wrong? Evolution ≠ Adaptation Writ Large Jeffrey H. Schwartz President, World Academy of Art & Science Departments of Anthropology and History and Philosophy of Science University of Pittsburgh
Gradual accumulation of infinitesimally small changes favored by natural selection because they are adaptively advantageous
In other words, Evolution is Adaptation writ large - which conflates two entirely different biological phenomena: 1) the advent of the feature/novelty (taxic diversity), and 2) the subsequent emergence of individual variation (i.e. slight degrees of difference in the expression of a feature or features among individuals of a species).
Thomas Henry Huxley and an alternative to gradualism - saltation: “…it is more than probable that the majority of varieties have arisen in [a] ‘spontaneous’ manner…[and] once in existence, varieties obey the fundamental law of reproduction that like tends to produce like, and their offspring exemplify it by tending to exhibit the same deviation from the parental stock as themselves.” (Huxley, 1860, review of Origin)
“…new forms must be produced by changes taking place in organisms in, after or before their birth, either in their embryonic, or toward or in their adult, condition.” (p. 233) St. George Mivart, the leading saltationist: “…it is probable that new species have appeared from time to time with comparative suddenness, and that they still continue so to arise if all the conditions necessary for specific evolution now obtain.” (p. 236)
Hugo de Vries Wm. Bateson Th. H. Morgan R. Goldschmidt O. Schindewolf Evolution and Adaptation must be decoupled!
Richard Goldschmidt: The Material Basis of Evolution (1940): Systemic mutations, ‘hopeful monsters’, cites Schindewolf (1936) for support from the fossil record “Micro-” versus “Macro-evolution” Repeated parts!!
Schindewolf on Goldschmidt’s Material Basis: “Th[e] explanatory attempt by Goldschmidt has aroused much opposition among other geneticists. Paleontology has no right to intervene on this dispute. From my personal point of view, I can add only that Goldschmidt’s inferences completely meet the challenge that fossil material appears to me to pose, and that he, a leading geneticist, has presented a completed interpretation that does justice to the tangible, historical phylogenetic data.” (Basic Questions, 1950, trans. 1993, p. 352; bold added)
Schindewolf’s overview: “The production of basic structural designs takes place independent of the environment and of the mode of life: the neomorphic organs are at first neutral with regard to their function and appropriateness; at first, their significance is completely incidental, and they do not attain value - and this usually in an environment different from the original one - until after they have acquired a certain degree of development and, with that, the capacity for being useful… the quality and quantity of neomorphs…are determined exclusively by the organism itself…you can’t make an elephant out of a mosquito [in other words, adult forms do not evolve].” (1950, trans. 1993, p. 372; bold/comment added added)
T. Dobzhansky (1941) Genetics & the Origin of Species (2nd ed) E. Mayr (1942) Systematics & the Origin of Species G. G. Simpson (1944) Tempo & Mode in Evolution The “modern synthesis”: constraining biology to a melding of Darwinism & Population Genetics
T. Dobzhansky re-writes Genetics and the Origin of Species (1st ed, 1937) basically to attack Goldschmidt: “ It is possible to imagine a mutation so drastic that its product becomes a monster hurling itself beyond the confines of species, genus, family, or class. But in what Goldschmidt has called the ‘hopeful monster’ the harmonious system, which any organism must necessarily possess, must be transformed at once into a radically different, but still sufficiently coherent, system to enable the monster to survive. The assumption that such a prodigy may, however rarely, walk the earth overtaxes one’s credulity, even though it may be right that the existence of life in the cosmos is in itself an extremely improbable event. ” (Genetics and the Origin of Species, 2nd ed, 1941: 52-53; bold added)
Mayr enters the fray - on speciation: “First, there is available in nature an almost unlimited supply of various kinds of mutations. Second, the variability within the smallest taxonomic units has the same genetic basis as…between subspecies [etc]…And third, selection, random gene loss, and similar factors, together with isolation, make it possible to explain species formation on the basis of mutability, without any recourse to Lamarckian forces.” “…the accumulation of small genetic changes in isolated populations can lead in the course of time to a new integrated genetic system, of such a difference that it thereby acquires all the characters of a new species, including reproductive isolation.” (Systematics and the Origin of Species, 1942: 70 & 158; bold added)
Simpson on Schindewolf (1936): “ After having carefully read the paper cited…it seems to me not only not to lead to some of the main conclusions of Goldschmidt but also to contradict them. This paper, although a theoretical work of great importance and value, is also in some respects, especially where it does approach Goldschmidt’s conclusions, at wide variance with the consensus of paleontologists and even with some of its own author’s other works.” (Tempo and Mode in Evolution, 1944: 58)
In 1949 Simpson continues his rejection of Schindewolf by suggesting why German scholars might think differently: “For some ten years Central Europe and the West have been separated by a highly effective intellectual isolating mechanism, only now beginning to break down. This barrier to inter-thinking virtually stopped the interchange of knowledge and ideas between the respective populations, within each of which the development of evolutionary theory continued independently of that within the other.” (1949, Evolution 3: 178; bold added)
Simpson continues: “Isolation has, of course, worked both ways; western students have been isolated from German scholars as much as the reverse. It is, however, assumed that readers of Evolution are…familiar with the main trends in western evolutionary studies during this period. These trends have been surprisingly uniform. Although using, at times, radically different data and working in widely distinct fields, [but] western students have in almost all cases tended toward a synthesis the core of which is the action of natural selection on genomes in populations.” (1949, Evolution 3: 178; bold/comment added)
Smoothly continuous, mostly gradual accumulation of small mutations producing slight morphological changes selected to allow the organism to adapt to its ever- changing environmental circumstances, eventually leading to evolutionary change. Evolution is Adaptation writ large, and that’s that.
Punctuated Equilibria vs Phyletic Gradualism: tempo “We postulate no ‘new’ type of selection” (Eldredge & Gould, 1972, p. 112)
Some of the backlash: “This idea is…a special case of Wright’s theory of random genetic drift as a mechanism for triggering shifts from one stable equilibrium (adaptive peak) to another.” “Evolution by jerks!” “Why do we need a new model when the one we already have works well enough?”
In order to be a true evolutionist, one must be entirely neo-Darwinian, and toe the line of the “synthesis” as conceived by Dobzhansky and Mayr via Morgan. The effect was and continues to be the squelching of alternative thinking - which was alive and well prior to 1941.
Jacob-Monod experiment (1961): absence (above) vs presence (below) of lactose
In the period of molecular systematics represented by the 1960s, concepts derived from study of the bacterial genome were extrapolated to multicellular organisms. That is: an integrated linear arrangement of DNA, with integrated DNA triplets (codons) that were translated into RNA codons that produced specific amino acids that formed a specific polypeptide. At the time, this extrapolation seemed reasonable.
Lenski and Trevisano (PNAS 81: 6814, 1994) The extrapolation of bacterial adaptation to multicelluar evolution
In contrast to bacteria, in which the promoter (non- coding) region is small and up to 98% of the genome is coding (i.e. results in metabolic activity), in multicellular organisms up to 98% of the genome is non-coding (introns, enormous promoter regions, junk DNA). (J. Eisen, Current Opinion in Microbiology 3: 475-480, 2000)
Conclusion: Adaptation (= survival of species) and Evolution (= introduction of novelty) must be decoupled conceptually and thus practically. Use of “evolution” outside its biological context continues its false conflation with “adaptation”. Social and biological change are different phenomena.
Conclusion: Social change might be conceived in terms of adaptation - as economists use the concepts “invention” and “innovation”. Even though we inherited the notion that “change” and “evolution” are synonymous terms, only multicellular organisms can evolve. Societies do not.
Conclusion: When one talks about evolution now in Homo sapiens, one is actually talking about adaptation, or in the Great Chain of Being sense, an “unfolding” - in this case the feedback effect of technological invention on exploiting the mental/neurological properties that have been there for at least 100 kya, since the first members of our species emerged.