Epistemic and community transition in American evolutionary studies: the ‘Committee on Common Problems of Genetics,Paleontology, and Systematics’ (1942–1949)

The Committee on Common Problems of Genetics, Paleontology, and Systematics (United States National Research Council) marks part of a critical transition in American evolutionary studies. Launched in 1942 to facilitate cross-training between genetics and paleontology, the Committee was also designed to amplify paleontologist voices in modern studies of evolutionary processes. During coincidental absences of founders George Gaylord Simpson and Theodosius Dobzhansky, an opportunistic Ernst Mayr moved into the project’s leadership. Mayr used the opportunity for programmatic reforms he had been pursuing elsewhere for more than a decade. These are evident in the Bulletins he distributed under Committee auspices. In his brief tenure as Committee leader, Mayr gained his first substantial foothold within the coalescing community infrastructure of evolutionary studies. Carrying this momentum forward led Mayr directly into the project to launch the journal Evolution. The sociology of interdisciplinary activity provides useful tools for understanding the Committee’s value in the broad sweep of change in evolutionary studies during the synthesis period.     

A sort of revolution: Systematics and physical anthropology in the 20th century

During the first four decades of the 20th century, a system of ideas about the evolution and systematics of humans and other primates coalesced around the work of George Gaylord Simpson and W. E. Le Gros Clark. Buttressed by the “new physical anthropology” of the 1950s, that system provided an authoritative model—a disciplinary matrix or paradigm—for the practice of that aspect of biological anthropology. The Simpson-Le Gros Clark synthesis began to unravel in the 1960s and collapsed in the 1970s under the onslaught of cladistic systematics. The cladistic “revolution” resembles a paradigm shift of the sort proposed by Thomas Kuhn because it was driven, not by new biological discoveries or theories, but by a change in aesthetics.     

'Molecules and monkeys': George Gaylord Simpson and the challenge of molecular evolution

In this paper, I analyze George Gaylord Simpson's response to the molecularization of evolutionary biology from his unique perspective as a paleontologist. I do so by exploring his views on early attempts to reconstruct phylogenetic relationships among primates using molecular data. Particular attention is paid to Simpson's role in the evolutionary synthesis of the 1930s and 1940s, as well as his concerns about the rise of molecular biology as a powerful discipline and world-view in the 1960s. I argue that Simpson's belief in the supremacy of natural selection as the primary driving force of evolution, as well as his view that biology was a historical science that seeks ultimate causes and highlights contingency, prevented him from acknowledging that the study of molecular evolution was an inherently valuable part of the life sciences.     

Evolutionary contingency and SETI revisited

The well-known argument against the Search for ExtraTerrestrial Intelligence (SETI) due to George Gaylord Simpson is re-analyzed almost half a century later, in the light of our improved understanding of preconditions for the emergence of life and intelligence brought about by the ongoing “astrobiological revolution”. Simpson’s argument has been enormously influential, in particular in biological circles, and it arguably fueled the most serious opposition to SETI programmes and their funding. I argue that both proponents and opponents of Simpson’s argument have occasionally mispresented its core content. Proponents often oversimplify it as just another consequence of biological contingency, thus leaving their position open to general arguments limiting the scope of contingency in evolution (such as the recent argument of Geerat Vermeij based on selection effects in the fossil record). They also tend to neglect that the argument has been presented as essentially atemporal, while referring to entities and processes that are likely to change over time; this has become even less justifiable as our astrobiological knowledge increased in recent years. Opponents have failed to see that the weaknesses in Simpson’s position could be removed by restructuring of the argument; I suggest one way of such restructuring, envisioned long ago in the fictional context by Stanislaw Lem. While no firm consensus has emerged on the validity of Simpson’s argument so far, I suggest that, contrary to the original motivation, today it is less an anti-SETI argument, and more an astrobiological research programme. In this research programme, SETI could be generalized into a platform for testing some of the deepest assumptions about evolutionary continuity and the relative role of contingency versus convergence on unprecedented spatial and temporal scales.     

John Salter and the Ediacara Fauna of the Longmyndian Supergroup

John W. Salter's papers of 1856 and 1857 reported trace and body fossils from rocks of the Longmyndian Supergroup, Shropshire, that conventional wisdom had deemed literally “Azoic.” The significance of this work is reflected by its mention in On the Origin of Species, where it is cited as evidence for the existence of life prior to the Cambrian radiation. This study of Salter's historic specimens combined with recent field studies confirms that these structures likely represent microbial rather than metazoan markings. Nevertheless, this review confirms Salter as the unheralded founder of Precambrian palaeontology, many years before the existence of a Precambrian fossil record was widely known. This study also gives credit to a highly skilled palaeontologist, who appears to have struggled with psychological problems throughout his life. Salter had once been Adam Sedgwick's “youthful and cheerful companion” in the field, prior to embarking on an initially successful Geological Survey career. He was a widely renowned expert on Palaeozoic palaeontology, especially trilobites, but eventually fell into serious depression, which culminated in his suicide in 1869. Study and reinterpretation of his original materials reaffirms the importance of Salter's discoveries, and the Longmynd for our understanding of late Ediacaran palaeobiology.     

Optical and conformational properties of the 7-(beta-D-ribofuranosyl) purines

The optical and conformational properties of certain 7-ribosyl purines have been studied using several experimental and theoretical methods. The CD, MCD, and absorption spectra of the 7-ribosyl purines and their cations have been determined experimentally with some solvent effects being noted. Theoretically we have used the SCF-CI and CNDO molecular orbital calculations to determine the optical properties of the bases; Simpson's bond exciton theory to determine the optical properties of the bases; Simpson's bond exciton theory to determine the optical properties of the ribose moiety; the optical activity was determined by the dipole coupling and electricmagnetic coupling equations; and the conformational energy calculations are included as a basis for excluding highly improbable conformations. On the basis of these calculations, we concluded that the oxy derivatives and the amino derivatives are predominately in the “extreme anti” conformation and “standard anti” conformation, respectively. However, the conclusions are tentative since at the present time the band assignments are not unequivocal. At least one n-π* transition has been identified in the spectra which is not notably sensitive to pH and solvent effects. Several implications of this observation are discussed.     

The promise of primatology fulfilled?

In 1972, Sherwood Washburn, one of the forerunners of biological anthropology, gave an invited address during the 4th Congress of the International Primatological Society in Portland, Oregon, in which he expounded his vision for the field of primatology. His address was published the following year in the American Journal of Physical Anthropology and titled: “The promise of primatology.” In this centennial commentary, we revisit Washburn's “promise”, 45 years on. His address and article discuss the constraints acting on the field, including a positioning of the discipline across different kinds of university departments, and within the social sciences, which he viewed as a mixed blessing. Prescient aspects of Washburn's address include a focus on the need to study communication multimodally, and a hope that the study of mechanisms would become foundational within the field. We discuss new promising aspects of primatology, focusing on technological advances in a number of areas highlighted by Washburn that have ushered in new eras of research, and the increasingly large number of long‐term field sites, which see the discipline well‐set for new developmental and longitudinal studies. We find much to admire in Washburn's keen foresight, and natural intuition. Washburn hoped that primatology would repudiate the notion that “the social should be studied without reference to the biological.” In this regard, we consider much of Washburn's promise fulfilled.     

Waiting for Sequences: Morris Goodman,Immunodiffusion Experiments,and the Origins of Molecular Anthropology

During the early 1960s, Morris Goodman used a variety of immunological tests to demonstrate the very close genetic relationships among humans, chimpanzees, and gorillas. Molecular anthropologists often point to this early research as a critical step in establishing their new specialty. Based on his molecular results, Goodman challenged the widely accepted taxonomic classification that separated humans from chimpanzees and gorillas in two separate families. His claim that chimpanzees and gorillas should join humans in family Hominidae sparked a well-known conflict with George Gaylord Simpson, Ernst Mayr, and other prominent evolutionary biologists. Less well known, but equally significant, were a series of disagreements between Goodman and other prominent molecular evolutionists concerning both methodological and theoretical issues. These included qualitative versus quantitative data, the role of natural selection, rates of evolution, and the reality of molecular clocks. These controversies continued throughout Goodman’s career, even as he moved from immunological techniques to protein and DNA sequence analysis. This episode highlights the diversity of methods used by molecular evolutionists and the conflicting conclusions drawn from the data that these methods generated.     

Prolegomenon to a history of paleoanthropology: The study of human origins as a scientific enterprise. Part 1. Antiquity to the eighteenth century

Interest in the history of paleoanthropology and the other disciplines related to human origins studies has grown considerably over the last several decades. Some very informative historical surveys have been written by prominent scientists reflecting on the major developments in their fields. Some well‐known early examples include Glyn Daniel's The Idea of Prehistory (1962) and The Origins and Growth of Archaeology (1967), which focus primarily on the history of archaeology, Kenneth Oakley's “The problem of man's antiquity: an historical survey” published in the Bulletin of the British Museum (Natural History) [Geology] (1964), and L. S. B. Leakey's Unveiling Man's Origins; Ten Decades of Thought about Human Evolution (1969), with the latter two focusing on the contributions of geology, paleontology, and biology to the problem of human evolution.     

Keeping up with Dobzhansky: G. Ledyard Stebbins, Jr., plant evolution, and the evolutionary synthesis

This paper explores the complex relationship between the plant evolutionist G. Ledyard Stebbins and the animal evolutionist Theodosius Dobzhansky. The manner in which the plant evolution was brought into line, synthesized, or rendered consistent with the understanding of animal evolution (and especially insect evolution) is explored, especially as it culminated with the publication of Stebbins's 1950 book Variation and Evolution in Plants. The paper explores the multi-directional traffic of influence between Stebbins and Dobzhansky, but also their social and professional networks that linked plant evolutionists like Stebbins with Edgar Anderson, Carl Epling, and the 'Carnegie team' of Jens Clausen, David Keck, and William Hiesey with collaborators on the animal side like I. Michael Lerner, Sewall Wright and L.C. Dunn and other 'architects' of the synthesis like Ernst Mayr, Julian Huxley and George Gaylord Simpson. The compatibility in training, work styles, methodologies, goals, field sites, levels of analysis, and even choice of organismic systems is explored between Stebbins and Dobzhansky. Finally, the extent to which coevolution between plants and insects is reflected in the relationship is explored, as is the power dynamic in the relationship between two of the most visible figures associated with the evolutionary synthesis.     

The rise of bilaterians: a few closing comments

Freeman (2009, 2010) argue that Ediacara “faunas” should be analysed using “promorphologies” of extant animals, that rangeomorphs and erniettomorphs are colonial animals, and that Vernanimalcula is a bilaterian animal. Recent studies of Ediacara fossils have provided multiple lines of evidence that these fossils represent a sample of phylogenetically diverse marine organisms that included crown-group animals as well as stem-group animals and non-animals. Thus, it is inappropriate to analyse Ediacara fossils using “promorphologies” of extant animals. The interpretation of rangeomorphs and erniettomorphs as colonial animals is inconsistent with the functional morphologies of these Ediacara fossils. Although Vernanimalcula is a fossil, the purported germ layers of Vernanimalcula are of diagenetic origin and there is no morphological evidence in support of its bilaterian affinity.     

Ape-like endocast of “ape-man” Taung

I have identified and illustrated a spherical “dimple” or “depression” on the Taung endocast as indicating the most likely position of the medial end of the lunate sulcus but have not drawn an actual lunate sulcus on Taung because one is not visible. In a recent paper, R.L. Holloway (Am. J. Phys. Anthropol. 77:27–33, 1988) drew a lunate sulcus on his copy of the Taung endocast, incorrectly attributed this sulcus to me, and used it to obtain a ratio of 0.254 to describe “Falk's” position of the lunate sulcus. My published ratio of 0.242 for Taung (Falk: Am. J. Phys. Anthropol. 67:313–315, 1985a) was not considered, although the focus of Holloway's paper was my assessment of the position of the lunate sulcus. Holloway also excluded published ratios for a chimpanzee in my collection from his statistical analysis but, even so, my published ratio for Taung is still only 1.5 standard deviations from his chimpanzee mean. If my chimpanzee brain is included in the sample, the ratio for Taung is 1.2 standard deviations from the mean. Furthermore, one of Holloway's own chimpanzees (B60–7) has a ratio of 0.241, just 0.001 below my ratio for Taung. There is no sulcus where Holloway has drawn one on Taung, his “F(LS)” is not mine, his 2 mm error is not mine, and the correct ratio for my measurement of Tuang is the one that I published, not the one that Holloway attributes to me. Assessment of Holloway's chimpanzee data supports my claim that the dimple on the Taung endocast is within the chimpanzee range for the medial end of the lunate sulcus.     

On concept formation in systematics

In his “Grundzüge einer Theorie der phylogenetischen Systematik”, Hennig (1950 ) cited three philosophers: the leading empiricist Rudolf Carnap, the conventionalist Hugo Dingler, and the somewhat more obscure empiricist Theodor Ziehen. David Hull characterized Hennig's “Grundzüge” as one long argument against idealistic morphology. It will here be argued that Hennig attacked idealistic morphology (synonymous with “systematic” morphology) for its mode of concept formation. Building on Carnap and Ziehen, who both looked back on Ernst Cassirer, Hennig argued that the “generic”, “thing” or “class” concept of traditional nomothetic science must be replaced with Cassirer's “relation concept.” According to Hennig, such “emancipation” of systematics from the Aristotelian “species” concept would also allow transcendence from the distinction of idiographic from nomothetic sciences, thus preserving the unity of science. However, the establishment of relations in the construction of a system of order presupposes entities that can be, or are, related. Relations presuppose relata, which in modern systematics are best conceptualized (at least at the supraspecific level) not as Aristotelian classes, nor as individuals as was argued by Hennig and Ziehen, but as tokens of natural kinds. © The Willi Hennig Society 2006.     

Sampling strategies for the assessment of tree species diversity

Abstract. This paper aims at proposing efficient vegetation sampling strategies. It describes how the estimation of species richness and diversity of moist evergreen forest is affected by (1) sampling design (simple random sampling, random cluster sampling, systematic cluster sampling, stratified cluster sampling); (2) choice of species richness estimators (number of observed species vs. non-parametric estimators) and (3) choice of diversity index (Simpson vs. Shannon). Two sites are studied: a 28-ha area situated in the Western Ghats of India and a 25-ha area located at Pasoh in Peninsular Malaysia. The results show that: (1) whatever the sampling strategy, estimates of species richness depend on sample size in these very diverse forest ecosystems which contain many rare species; (2) Simpson's diversity index reaches a stable value at low sample sizes while Shannon's index is affected more by the addition of rare species with increasing sample size; (3) cluster sampling strategies provide a good compromise between cost and statistical efficiency; (4) 300 - 400 sample trees grouped in small clusters (10–50 individuals) are enough to obtain unbiased and precise estimates of Simpson's index; (5) the local topography of the Western Ghats has a major influence on forest composition, the steep slopes being richer and more diverse than the ridges and gentle slopes; (6) stratified cluster sampling is thus an interesting alternative to systematic cluster sampling.     

Species and paleoanthropology

The biotic world is self-evidently “packaged” into units, of which the most basic is the species. It is necessary to develop an accurate understanding of what species are and how they are to be identified before we can proceed to more complex analyses of the evolutionary histories and relationships of extinct and extant taxa at all levels of the systematic hierarchy. In this article, we review the major species concepts current today among paleoanthropologists, and examine the limitations of their applicability to practical studies of extant and extinct faunas. The primary such limitation for paleoanthropologists is the fact that all major species definitions stress reproductive continuity (whether by exclusionary or inclusionary mechanisms), a quality that is inferential at best among forms known only as fossils (and, in many cases, in the extant fauna as well). The only reliable signal as to species status in the fossil record is morphology, yet speciation carries with it no specifiable quantity of morphological innovation. Some groups with autapomorphies are not species, and some species do not bear autapomorphies. How, then, are we to recognize species in the hominid and other fossil records? Noting that osteodental differences among congeneric primate species tend to be subtle, and that when consistent identifiable “morphs” can be found at least as many species are present, we recommend equating morphs based on several characters with species—realizing that only one or two distinctive characters may not make a morph. In this way, our views of the phylogenetic histories of higher taxa may be oversimplified, but their essential patterns will not be distorted.     

Ulisse Aldrovandi (1522–1605): The Study of Trace Fossils During the Renaissance

The Renaissance was a time of flourishing for literature, art and science. A prominent figure in Renaissance science was the Italian naturalist Ulisse Aldrovandi, considered today to be one of the founding fathers of modern paleontology. Aldrovandi is known to have widely studied body fossils, but his work on trace fossils has yet to be explored by science historians. This paper proposes to critically analyze Aldrovandi's approach to trace fossils, based on his writings (most of which are still unpublished) and on the illustrations that accompany them. In his studies, the Bologna-born naturalist accurately describes such ichnological celebrities as Gastrochaenolites and Cosmorhaphe and discusses a few theoretic principles on the trace-making process. The study of the works of Aldrovandi brings to light a fascinating and little-known source of the history of ichnology.     

EARLY BURSTS OF BODY SIZE AND SHAPE EVOLUTION ARE RARE IN COMPARATIVE DATA

George Gaylord Simpson famously postulated that much of life's diversity originated as adaptive radiations—more or less simultaneous divergences of numerous lines from a single ancestral adaptive type. However, identifying adaptive radiations has proven difficult due to a lack of broad‐scale comparative datasets. Here, we use phylogenetic comparative data on body size and shape in a diversity of animal clades to test a key model of adaptive radiation, in which initially rapid morphological evolution is followed by relative stasis. We compared the fit of this model to both single selective peak and random walk models. We found little support for the early‐burst model of adaptive radiation, whereas both other models, particularly that of selective peaks, were commonly supported. In addition, we found that the net rate of morphological evolution varied inversely with clade age. The youngest clades appear to evolve most rapidly because long‐term change typically does not attain the amount of divergence predicted from rates measured over short time scales. Across our entire analysis, the dominant pattern was one of constraints shaping evolution continually through time rather than rapid evolution followed by stasis. We suggest that the classical model of adaptive radiation, where morphological evolution is initially rapid and slows through time, may be rare in comparative data.     

The proximate/ultimate distinction in the multiple careers of Ernst Mayr

Ernst Mayr's distinction between “ultimate” and “proximate” causes is justly considered a major contribution to philosophy of biology. But how did Mayr come to this “philosophical” distinction, and what role did it play in his earlier “scientific” work? I address these issues by dividing Mayr's work into three careers or phases: 1) Mayr the naturalist/researcher, 2) Mayr the representative of and spokesman for evolutionary biology and systematics, and more recently 3) Mayr the historian and philosopher of biology. If we want to understand the role of the proximate/ultimate distinction in Mayr's more recent career as a philosopher and historian, then it helps to consider hisearlier use of the distinction, in the course of his research, and in his promotion of the professions of evolutionary biology and systematics. I believe that this approach would also shed light on some other important “philosophical” positions that Mayr has defended, including the distinction between “essentialism: and “population thinking.”     

Rereading the Gods Must be Crazy Films

Studies of Jamie Uys's Gods Must be Crazy films have tended to focus on his pseudo-ethnographic representation of “Bushmen,” from primarily Western perspectives, both anthropological and anti-apartheid. This study examines critically the wider corpus of Uys's feature films, especially those employing “Bushmen” characters, in terms of intertextual relations. The article offers the comments of many San viewers of the films and also conveys the perspective of Gao, the main Ju/'hoansi actor. Finally, the study examines responses from the anthropological community to the films.