by Richard Peachey
During recent Web interactions with opponents of creation, I have been accused of putting the terms "macroevolution" and "microevolution" into the mouths of evolutionists. One (anonymous) blogger responded to me, ". . . macroevolution and microevolution are made-up creationist terms. there's no reason that an actual scientist would ever use them, as the distinction that they purport to describe is a fiction of the denialists." Another correspondent, a retired UBC physics professor, told me in a personal email, "Biologists like [Stephen Jay] Gould usually refrain from using marco- [sic ] and micro- evolution because of its use by creationists and intelligent designers."
To the latter writer, I sent the following detailed response:
. . . I will now offer several quotations from scientific journals showing that (a) evolutionists do in fact use those words; (b) the words were actually invented by a noted evolutionist; and (c) a significant number of evolutionists do regard microevolution and macroevolution as "decoupled" in the sense that the mechanisms of microevolution will not automatically, with the mere addition of time, result in macroevolution (thus such evolutionists would readily distinguish large-scale evolution from an intraspecific case like the peppered moth story). I am providing you with a lot of quotations because I would not want you to be tempted to dismiss what I'm saying as the uninformed carelessness of just a few fringe individuals. (Note: Bold print in the following quotes indicates emphasis added.)
(1) "Whether macroevolution is merely microevolution writ long has been a prominent debate in biology, with protagonists often talking at cross purposes. Some paleo-biologists have stressed that long-term evolutionary phenomena, such as stasis, mass extinctions and adaptive radiations, cannot be predicted from population genetic theory, insisting that additional macroevolutionary laws applicable over vast timescales are needed [1-3]. Population biologists have countered by stressing that these phenomena are nevertheless consistent with microevolutionary principles, rendering additional laws unnecessary or, at best, speculative and untestable [4,5]." (Michael S. Y. Lee and Paul Doughty, "The geometric meaning of macroevolution." Trends in Ecology and Evolution 18(6):263, June 2003. The square-bracketed reference numbers 1-3 and 4,5 are part of the article's text. Interestingly, of the five items referenced, two include the concept of "macroevolution" in their very titles. Reference 2 is "Jablonski, D. (1986) Background and mass extinctions: the alternation of macroevolutionary regimes. Science 231, 129-133". Reference 4 is "Charlesworth, B. et al. (1982) A Neo-Darwinian commentary on macroevolution. Evolution 36, 474-498".)
(2) "Evolutionary biologists have long sought to understand the relationship between microevolution (adaptation), which can be observed both in nature and in the laboratory, and macroevolution (speciation and the origin of the divisions of the taxonomic hierarchy above the species level, and the development of complex organs), which cannot be witnessed because it occurs over intervals that far exceed the human lifespan. . . . [from the abstract ]
"Macroevolution posed a problem to Darwin because his principle of descent with modification predicts gradual transitions between small-scale adaptive changes in populations and these larger-scale phenomena, yet there is little evidence for such transitions in nature. Instead, the natural world is often characterized by gaps, or discontinuities. One type of gap relates to the existence of 'organs of extreme perfection', such as the eye, or morphological innovations, such as wings, both of which are found fully formed in present-day organisms without leaving evidence of a transition between them. These discontinuities, plus the discontinuous appearance and disappearance of taxa in the fossil record, form the modern conceptual divide between microevolution and macroevolution. . . .
"Most evolutionary biologists think that Darwin explained macroevolution simply as microevolution writ large. In fact, Darwin had rather more to say about the relationship between microevolution and macroevolution and invoked additional principles to define it. . . . [Note: The authors do not mean to imply that Darwin himself used these terms.]
"An undercurrent of the debate about the mechanisms of macroevolution is whether natural selection (microevolution) is also the cause of macroevolution. . . . [from Box 1 ]
"Darwin's proposal carries a more general message for contemporary discussions of macroevolution, namely that microevolution alone cannot explain macroevolution." (David N. Reznick and Robert E. Ricklefs, "Darwin's bridge between microevolution and macroevolution." Nature 457:837,838,841, Feb. 12, 2009)
(3) "Speakers at the 'Macroevolution: Evolution above the Species Level' symposium, held at the National Association of Biology Teachers annual meeting last October, focused on macroevolutionary processes, the evolution of key innovations and major lineages of organisms, and the evidence for these processes. . . . [from the abstract ]
"'Some in the antievolution community assert that microevolution happens but not macroevolution,' Gordon Uno, chair of the AIBS [American Institute of Biological Sciences] education committee, pointed out in his opening remarks, 'because they believe there is no evidence for it.' . . .
"In her closing remarks, Kathleen Smith, director of NESCent [National Evolutionary Synthesis Center] and professor biology at Duke University in Durham, North Carolina, summed up the salient points of the symposium:
"The genetic toolkit is important in the study of macroevolution. The same set of genes are used again and again, so that major evolutionary change does not necessarily require major genetic changes.
"There is complexity in the tempo and mode of evolution. There are many different patterns in macroevolutionary events.
"Many macroevolutionary changes depend on significant changes in the environment, some of which may have led to large extinction events.
"The processes of microevolution and macroevolution are continuous." (Oksana Hlodan, "Macroevolution: Evolution above the Species Level." BioScience 57(3):222,225. March, 2007)
(4) "Evolutionary change occurs on different scales: 'microevolution' is generally equated with events at or below the species level whereas 'macroevolution' is change above the species level, including the formation of species. A long-standing issue in evolutionary biology is whether the processes observable in extant populations and species (microevolution) are sufficient to account for the larger-scale changes evident over longer periods of life's history (macroevolution).
"Outsiders to this rich literature may be surprised that there is no consensus on this issue, and that strong viewpoints are held at both ends of the spectrum, with many undecided. Traditionally, evolutionary geneticists have asserted that macroevolution is the product of microevolution writ large, whereas some palaeontologists have advocated the view that processes operating above the level of microevolution also shape evolutionary trends. . . .
"One of the evolutionary phenomena for which the mechanistic discontinuity between macroevolution and microevolution has most often been asserted is the burst of innovation and diversification associated with major radiations of forms—for example, the dramatic phyletic and morphological evolution seen in the explosive Cambrian radiation of animal phyla." (Sean B. Carroll, "The big picture." Nature 409:669, Feb. 8, 2001)
(5) "A wide spectrum of researchers—ranging from geologists and paleontologists, through ecologists and population geneticists, to embryologists and molecular biologists—gathered at Chicago's Field Museum of Natural History under the simple conference title: Macroevolution. Their task was to consider the mechanisms that underlie the origin of species and the evolutionary relationships between species. . . .
"The changes within a population have been termed microevolution, and they can indeed be accepted as a consequence of shifting gene frequencies. Changes above the species level—involving the origin of new species and the establishment of higher taxonomic patterns—are known as macroevolution. The central question of the Chicago conference was whether the mechanisms underlying microevolution can be extrapolated to explain the phenomena of macroevolution. At the risk of doing violence to the positions of some of the people at the meeting, the answer can be given as a clear, No. What is not so clear, however, is whether microevolution is totally decoupled from macroevolution: the two can more probably be seen as a continuum with a notable overlap." (Roger Lewin, "Evolutionary Theory Under Fire." Science 210:883, Nov. 21, 1980)
(6) "The central question of macroevolution concerns the evolution of major morphological innovations (and major taxonomic groups). It is a matter of scale rather than simply rate of evolution or hierarchical level of mechanism. Through the history of microevolutionary theory there is a constant counterpoint of macroevolutionary questioning: are current versions of microevolution sufficient to explain the data concerning origins of major novelties? . . . [from the abstract ]
"For a hundred and fifty years we have seen paleontology, morphology, genetics, and development wax and wane as dominant evolutionary disciplines (the custodians of the answers, as it were), but largely with no effect on the basic macroevolution problem of how major events that appear to happen very quickly can also be gradual. . . .
"The basic article of faith of a gradualist approach is that major morphological innovations can be produced without some sort of saltation. But the dilemma of the New [i.e., neo-Darwinian] Synthesis is that no one has satisfactorily demonstrated a mechanism at the population genetic level by which innumerable very small phenotypic changes could accumulate rapidly to produce large changes: a process for the origin of the magnificently improbable from the ineffably trivial. This leads to skepticism about the microevolutionary approach. . . .
"In looking back over the literature of the last 60 years, it is fascinating that throughout the whole grand development of the New Synthetic theory, the macroevolutionary question remains as a constant undercurrent. . . .
"In one of the most influential books of the New Synthetic approach as it evolved in Britain and the United States, Dobzhansky (1937) was quite circumspect about 'the mechanisms of a macroevolution, which require time on a geological scale.' However '. . . we are compelled at the present level of knowledge reluctantly to put a sign of equality between the mechanisms of macro- and micro-evolution, and proceeding on this assumption, to push our investigations as far ahead as this working hypothesis will permit.' " (Keith Stewart Thomson, "Macroevolution: The Morphological Problem." American Zoologist 32:106,107, 1992)
(7) "The words micro- and macro-evolution do appear in the scientific literature—which, of course, is where creationists got them to begin with. . . .
"Most professional biologists today think of microevolution as evolution within species and of macroevolution as what happens over time to differentiate species or 'higher' groups of organisms (genera, families, etc.). . . .
"I recently returned from a three-day conference at Indiana University on the problem of evolutionary novelties. No creationist there, but little agreement among the scientists present on what the best explanations are for the appearance of novelties. Some of my more conservative colleagues—like Darwin before them—saw no problem at all, arguing that the conceptual tools of the Modern [i.e., neo-Darwinian] Synthesis are sufficient for the task and we only need to work out the details. Others, including myself, disagreed and proposed a variety of other venues of inquiry (including somewhat obscure phenomena like phenotypic plasticity, epigenetic inheritance, and emergent complexity). . . .
"The reason I think creationists, and the public at large, are not well served by scientists in this case is because few evolutionary biologists talk to the public to begin with, and when they are confronted with the micro/macro question, they simply accuse creationists of making up such a distinction and move on. What they (we) should say is that there is indeed genuine disagreement among professional biologists about the meaningfulness of the concept, and even those who agree that there is something to it are still trying to figure out an explanation." (Massimo Pigliucci, "Is There Such a Thing as Macroevolution?" Skeptical Inquirer 31(2):18,19, March/April, 2007. This is not a scientific journal, of course, but Pigliucci is a prominent professor of evolutionary biology and philosophy.)
(8) "[Theodosius Dobzhansky's teacher] I. A. Filipchenko (1929) coined the terms microevolution and macroevolution and argued that one could not be inferred from the other. Microevolution concerned the origin of varieties and races within species. Macroevolution concerned the origins of higher taxa. . . . One of the major tenets of the Modern Synthesis has been that of extrapolation: the phenomena of macroevolution, the evolution of species and higher taxa, are fully explained by the microevolutionary processes that gives [sic] rise to varieties within species. Macroevolution can be reduced to microevolution. That is, the origins of higher taxa can be explained by population genetics. . . .
"The concept that macroevolution could not be derived from microevolution remained as an underground current in evolutionary theory. Every so often, it was brought to the surface by developmentally oriented evolutionary biologists such as Goldschmidt, Waddington, or de Beer. In 1940, Richard Goldschmidt stated the challenge to those who proposed the Modern Synthesis. How could the origin of such things as mammalian hair, aortic arches, mollusc shells, cnidocysts, or the compound eye be explained 'by accumulation and selection of small mutants'? But these attempts to decouple microevolution from macroevolution were either ignored or marginalized. . . .
"Macroevolution was brought back as an autonomous entity only after Eldredge and Gould (1972), Stanley (1979), and others postulated an alternative view to the gradualism that characterized the Modern Synthesis. By 1980, Gould claimed that the idea of 'gradual alleleic [sic] substitution as a mode for all evolutionary change' was effectively dead. This view did not go unchallenged, and by 1982, Gould's view had become more specific. It wasn't that the Modern Synthesis was wrong; rather, it was incomplete. 'Nothing about microevolutionary population genetics, or any other aspect of microevolutionary theory, is wrong or inadequate at its level. . . . But it is not everything' (Gould, 1982; p. 104 [ellipsis is the authors' ]). While punctuated equilibrium remained a controversial theory, it did bring to light the question of the autonomy of macroevolution. Indeed, the failure of microevolutionary biology to distinguish between punctuated equilibrium and gradualism demonstrated its weakness when applied to macroevolution (see Ayala, 1983). Molecular studies (King and Wilson, 1975) were similarly pointing to 'evolution at two levels,' one molecular, the other morphological. Thus, by the early 1980s, numerous paleontologists and evolutionary biologists (Gould, Stanley, Eldredge, Verba [sic, should be Vrba], and most critically, Ayala) came to the conclusion that although macroevolutionary phenomena were underlain by microevolutionary phenomena, the two areas were autonomous and that macroevolutionary processes could not be explained solely by microevolutionary events." (Scott F. Gilbert, John M. Opitz, and Rudolf A. Raff, "Resynthesizing Evolutionary and Developmental Biology." Developmental Biology 173:358,362, 1996)
(9) Stephen Jay Gould was not averse to using the terms microevolution and macroevolution. See this 1983 book, in which Gould's own chapter repeatedly uses the terms (pages 347, 351, 352, 354, 355, 356, 358, 364); also Francisco J. Ayala's chapter cites Gould using the terms (pages 387, 388). See also Gould's 1994 paper in which the terms appear throughout. Finally, note that Gould continued to use the terms even in his magnum opus, The Structure of Evolutionary Theory, published in 2002, the year of his death. This can be seen in the quotations given by Francisco J. Ayala in his review of Gould's book (Theology and Science 3(1), 2005). Note especially pages 97, 99, 100, 101 of Ayala's review.
(10) For a sampling of journal articles more recent than the ones I've cited, you can go to PubMed and enter either "macroevolution" or "microevolution" as your search term. Hundreds of up-to-date articles on those topics will come up. Some of them will even contain those terms in their titles.
My point above is reinforced in an earlier article by Intelligent Design advocate Casey Luskin:
"Busting another Darwinist Myth: Have ID Proponents Invented Terms like 'Microevolution' and 'Macroevolution'?"