Macrodevelopment

Macrodevelopment is a biological hypothesis that proposes over millions of years the biosphere has nonlinearly unfolded taxa from generic forms to specific forms, in a manner analogous to the way in which a biological embryo develops in the womb. The theory was created by Robert F. DeHaan.

IntroductionEvolution, not development, occupies the high theoretical ground in biology and biohistory,indeed, in the scientific community as a whole, and in large sectors of western societyas well. The hegemony of evolution was clearly articulated by Theodosius Dobzhansky inhis manifesto, “Nothing in Biology Makes Sense Except in the Light of Evolution.”1 Evolutionaryliterature invokes this slogan endlessly, reinforcing the view that evolutionary theoryis the indispensable and only possible scientific theory of origins and change in the history oforganic life.2 The purpose of this essay is to make a brief evaluation of evolution from theperspective of macro-development in order to determine whether Dobzhansky is right. Isevolution essential for biology and does it shed light on all of biology?DEFINITIONS OF EVOLUTIONWhat is evolution? The problem with defining the term is that the concept of evolutionis subject to so many interpretations it is nearly impossible to find its core meaning. It isnot considered a single unitary concept by some authors.3 It has even been called a smorgasbordof concepts.4 The lack of a clear, consistent definition of evolution poses a problem forthose who wish to engage in a disciplined, critical discussion of it. What does Dobzhanskymean by “evolution” when he claims that nothing in biology makes sense without it?Let us begin with a brief summary of evolution given by Plantinga:5Organic life somehow arose from non-living matter by way of purely naturalistic meansand by virtue of the workings of fundamental regularities of physics and chemistry. Oncelife began, all the vast profusion of contemporary flora and fauna arose from those earlyancestors by way of common descent. The enormous contemporary variety of life arose,basically through natural selection operating on such sources of genetic variability as randomgenetic mutation, genetic drift and the like.6We will examine this definition more closely in the light of three meanings of the term,evolution, which have been provided by Thomson7 that help pin down the concept. They are1) change over time, 2) descent with modification from a common ancestor, and 3) naturalselection.Change Over TimeIn the first, most general sense, evolution is said to mean change over time. Thomsonasserted that “change over [geologic] time is the most solidly based fact of evolution.” Whereverone finds biological change occurring over long periods of time, according to this definition,there one finds evolution as the causal agent. This view fits hand-in-glove withDobzhansky’s manifesto, and is probably the most widely employed meaning of the term.This broad definition, linking all organic change over time with evolution, along withDobzhansky’s manifesto, establishes the hegemony of evolutionary theory since by definitionevolution becomes an established fact.There are three major defects in this interpretation of evolution. First, it is so broadand general that it defeats the purpose of clear, concise definitions, so necessary in science. Itcan cover almost any kind of long-term biological or paleontological change and thus losesits meaning. Second, and more important, it effectively stifles scientific skepticism, that attitudewhich scientists prize so highly and exercise so vigorously, but only rarely in evolutionarystudies. What happens when a “change over time” is discovered in the fossil record whichdoesn’t fit neatly into the evolutionary paradigm, as is the case, for instance, with the Cambrianexplosion that occurred 530 million years ago? No need to think critically or to searchfor an alternative, non-evolutionary explanation. “Change over time” explains it all. That’sit. Such an uncritical attitude, we hold, is not good science.Third, Thomson’s claim is an overstatement. Not every biological organism or systemchanges. Body plans, i. e., the basic architecture of all major groups of animals, called phyla,have remained essentially unchanged from the time they came into existence, more than 500million years ago. How does one account for their permanence? Are they immune fromThomson’s first definition?In sum, Thomson’s first definition, is overly broad, inhibits critical thinking and thesuppresses the search for alternative explanations. It does not allow consideration of an alternativeposition—the indispensable role played by macro-development as a major source ofchange over time as discussed in the previous essay.Relation Through Common AncestryThe second important meaning of evolution, according to Thomson,8 is that all organismsare related through common ancestry, the process of descent with modification from a singlecommon ancestor. All forms of life are thus allegedly interrelated. Descent with modificationand the unbroken continuity of life, however, are merely assumptions or hypotheses, notobjective facts, according to Thomson. He is right. Evolution predicts or hypothesizes commonancestry of all organisms because that’s theoretically what evolution should produce.9But is common ancestry born out by the facts?Recently reported research calls into question the validity of common ancestry.10 Theresearch focused on three very simple, but fundamental organisms, 1) yeast; 2) the bacterium,E. coli; and 3) the primitive bacterium called archaebacterium. These three simple organismsare important because they represent the three kingdoms of life, the highest, most importantdivision of living organisms—eukaryotes, eubacteria, and archaebacteria. If there is a commonancestor, these simple, ancestral organisms should show it. But do they? The answer isno. They are found to be so genetically different from each other that it is hard to justify usingone to explain the workings of another. Each has many unique genes that are not shared bythe other organisms; they share only a small set of common genes. The authors of the studystate:In a real sense, organisms that contain unique constituent parts cannot be models foranother.…that is [they cannot be] physiological representative of many other organisms.Having the whole genomes spread out for our examination underscores how different fromone another these organisms are (Emphasis added).In sum, the simplest representatives of the three kingdoms are genetically verydifferent from each other. This makes it very difficult to maintain that they descendedfrom a common ancestor. Thus, from the very start the kingdoms lack commonalty; theyare discontinuous from each other.Natural SelectionThe third meaning of evolution is natural selection. In its historic meaning, naturalselection occurs through small, accidental genetic variations, called mutations, in the germcells of individual organisms, and the sorting out by the environment of the most adaptableand reproductively successful organisms produced by these mutations. Thus the fittest surviveand reproduce. With the increase in the number of offspring of the most adaptive animalsor plants the favorable mutation spreads through the population.Natural selection is the historical core of evolutionary theory. It will be called “Darwinianevolution” because it was formulated by Darwin and remains the most basic meaningof evolution. Darwin asserted, “If it could be demonstrated that any complex organ existed,which could not possibly have been formed by numerous successive, slight modifications,my theory would absolutely break down.”11 It is the universal causal mechanism underlyingThomson’s first two definitions of change over time and descent with modification. Withoutit they become merely descriptive statements. Thomson holds that the theory of naturalselection has not seriously changed since Darwin’s day.12Alternative definitions. The centrality of natural selection, however, is not acceptedby all modern biologists. “The entire body of technical advance in experimental and theoreticalevolutionary genetics of the last fifty years has moved in the direction of emphasizingnon-selective forces in evolution.”13 The move has been toward genetic definitions of evolution.One such definition is “change in gene composition of a population.” According toGilbert14 and his colleagues, “The Modern Synthesis supported population genetics as themajor focus of evolutionary science and viewed genetics as ‘Darwin’s missing evidence’….Thusevolution could be completely explained by the mutation and separation of genes.” Accordingto Strickberger,15 gene-frequencies in a population change in a directional way by meansof mutations, selection, migration of genes from one population to another. Neutral mutations,random mutations and genetic drift are claimed by some also to be important in changinggene frequencies in non-directional, non-selective ways.16Criticisms of genetic definitions of evolution. Genetic definitions of evolution, emphasizingthe genetic composition of populations rather than environmental sorting, alsohave their critics.17 As Wells18 reported,Efforts to correlate evolution with changes in gene frequencies have not been verysuccessful. Detailed studies at the molecular level fail to demonstrate the expected correspondencebetween changes in gene products and the sorts of organismal changes which constitute [what Lewontin called] the “stuff of evolution.”It does not matter, moreover, to the theory of phylo-development whether the mechanismof evolution is a Darwinian mechanism, such as natural selection, or an alternative evolutionarymechanism. None is adequate to explain macroevolution—the origin and historyof major innovations such as phyletic lineages, to be discussed below. They explain, at best,only microevolution, not macroevolution. These terms will be discussed in detail below.Why has there been such a proliferation of alternative definitions to natural selection?We suggest that they arise because of the failure of the historical, Darwinian concept of naturalselection to provide a compelling explanation of major events in the history of organic life,such as the spectacular rise of 50 or so phyla in the Cambrian explosion, and how these phylachanged over time in the history of complex, multisystem life.These definitions of evolution and the definition of phylo-development may be comparedwith each other by employing two useful terms introduced by Raff,19 programmed andunprogrammed changes. Development and phylo-development are programmed changes, asdiscussed in the previous essay. Development is described in scientific literature as a goaldirected,20 internally driven and programmed,21 hierarchical process22—in stark contrast toevolution. All meanings of evolution are subsumed under unprogrammed— unplanned,23random (i.e., purposeless), externally directed process of natural selection of Darwinian evolution.24

References

* [http://www.macrodevelopment.org/ MacroDevelopment Home Page]
* [http://www.farfromequilibrium.com/Lhm_site/new_theory.html A New Theory of Evolution]
* [http://www.farfromequilibrium.com/Lhm_site/New_Evolutionary_Theory.pdf New Evolutionary Theory: The End of Ideology] (pdf)