Functional Morphology in Paleobiology: Origins of the Method of ‘Paradigms’

From the early nineteenth century, the successful use of fossils in stratigraphy oriented paleontology (and particularly the study of fossil invertebrates) towards geology. The consequent marginalising of biological objectives was countered in the twentieth century by the rise of ‘Paläobiologie’, first in the German cultural area and only later, as ‘paleobiology’, in the anglophone world. Several kinds of paleobiological research flourished internationally after the Second World War, among them the novel field of ‘paleoecology’. Within this field there were attempts to apply functional morphology to the problematical cases of fossil organisms, for which functions cannot be observed directly. This article describes the origins of the kind of functional inference for fossils that I proposed in 1961 as the method of ‘paradigms’ (a year before Thomas Kuhn made that word more widely familiar with a quite different meaning). Here I summarize some of my ‘worked exemplars’, which were intended to show the paradigm method in action. These case-studies were all taken from the paleontologically important phylum of the Brachiopoda, but the method was claimed to have much wider implications for the interpretation of the fossil record in terms of adaptive evolution. This article takes the history of the paradigm method as far as the late 1960s. I hope to trace, in a sequel, its ambivalent fate during the 1970s and beyond, when for example Gould’s critique of ‘the adaptationist programme’ and the rise of computer-based quantitative methods for the evolutionary interpretation of the fossil record led to the relative eclipse of functional morphology in paleontology.     

Towards “A Natural History of Data”: Evolving Practices and Epistemologies of Data in Paleontology, 1800–2000

The fossil record is paleontology’s great resource, telling us virtually everything we know about the past history of life. This record, which has been accumulating since the beginning of paleontology as a professional discipline in the early nineteenth century, is a collection of objects. The fossil record exists literally, in the specimen drawers where fossils are kept, and figuratively, in the illustrations and records of fossils compiled in paleontological atlases and compendia. However, as has become increasingly clear since the later twentieth century, the fossil record is also a record of data. Paleontologists now routinely abstract information from the physical fossil record to construct databases that serve as the basis for quantitative analysis of patterns in the history of life. What is the significance of this distinction? While it is often assumed that the orientation towards treating the fossil record as a record of data is an innovation of the computer age, it turns out that nineteenth century paleontology was substantially “data driven.” This paper traces the evolution of data practices and analyses in paleontology, primarily through examination of the compendia in which the fossil record has been recorded over the past 200 years. I argue that the transition towards conceptualizing the fossil record as a record of data began long before the emergence of the technologies associated with modern databases (such as digital computers and modern statistical methods). I will also argue that this history reveals how new forms of visual representation were associated with the transition from seeing the fossil record as a record of objects to one of data or information, which allowed paleontologists to make new visual arguments about their data. While these practices and techniques have become increasingly sophisticated in recent decades, I will show that their basic methodology was in place over a century ago, and that, in a sense, paleontology has always been a “data driven” science.     

Evolution in fossil lineages: paleontology and The Origin of Species

Of all of the sources of evidence for evolution by natural selection, perhaps the most problematic for Darwin was the geological record of organic change. In response to the absence of species-level transformations in the fossil record, Darwin argued that the fossil record was too incomplete, too biased, and too poorly known to provide strong evidence against his theory. Here, this view of the fossil record is evaluated in light of 150 years of subsequent paleontological research. Although Darwin's assessment of the completeness and resolution of fossiliferous rocks was in several ways astute, today the fossil record is much better explored, documented, and understood than it was in 1859. In particular, a reasonably large set of studies tracing evolutionary trajectories within species can now be brought to bear on Darwin's expectation of gradual change driven by natural selection. An unusually high-resolution sequence of stickleback-bearing strata records the transformation of this lineage via natural selection. This adaptive trajectory is qualitatively consistent with Darwin's prediction, but it occurred much more rapidly than he would have guessed: almost all of the directional change was completed within 1,000 generations. In most geological sequences, this change would be too rapid to resolve. The accumulated fossil record at more typical paleontological scales (10(4)-10(6) years) reveals evolutionary changes that are rarely directional and net rates of change that are perhaps surprisingly slow, two findings that are in agreement with the punctuated-equilibrium model. Finally, Darwin's view of the broader history of life is reviewed briefly, with a focus on competition-mediated extinction and recent paleontological and phylogenetic attempts to assess diversity dependence in evolutionary dynamics.     

Interactions within and between clades shaped the diversification of terrestrial carnivores

A longstanding debate in evolutionary biology and paleontology is whether ecological interactions such as competition impose diversity dependence on speciation and extinction rates. Here, we analyze the fossil record of terrestrial mammalian carnivores in North America and Eurasia using a Bayesian framework to assess whether their diversity dynamics were affected by diversity dependence within and between families (12 in Eurasia, 10 in North America). We found eight instances of within‐clade diversity dependence suppressing speciation rates and detected between‐clade effects increasing extinction rates in six instances. Diversity dependence often involved lineages that migrated between continents and we found that speciation was more responsive to diversity changes within the clade, whereas extinction responded to diversity of taxa in other clades. The analysis of the fossil record of Carnivora suggests that interactions within and between clades are associated with different speciation and extinction regimes, opening room for a broader theory of diversity dependence.     

北美西部古新世-始新世极热事件(PETM)期间的哺乳动物群序列(英文)

跟随一队研究哺乳动物群在古新世-始新世变化的生物地层学和古地理学的学者,已故周明镇教授开始了他的古脊椎动物学事业。这是化石记录中偶蹄类、奇蹄类和灵长类(APP类群)首次出现的时期。随着北美西部Polecat Bench新的最晚古新世Clarkforkian哺乳动物群的发现,古新世作为一个独立于始新世的分期从1911年开始被接受。后来,研究证明古新世-始新世界线包括了一段时间,这期间发育了矮小型哺乳动物支系。古新世-始新世碳同位素漂移(CIE)与哺乳动物矮小化以及APP类群的首次出现是同时的。据此可以对CIE进行全球性总结,结果表明它与古新世-始新世极热事件(PETM)相关。PETM这一全球温室变暖事件不仅对地球气候和生物群有短暂的影响,而且对生物群同样具有深远持续的影响。我们所知的哺乳动物与CIE和PETM之间关系的大部分内容是通过对Polecat Bench周边剖面独特地层记录的高分辨率研究得到的。周教授早年曾在那里工作过,如今他的骨灰也撒在那里。     

中国中生代哺乳类化石

本文对迄今所知的中国中生代哺乳类的化石地点、层位、时代、化石材料和系统分类位置作了总结和讨论。     

Darwin was a teleologist

It is often claimed that one of Darwin's chief accomplishments was to provide biology with a non-teleological explanation of adaptation. A number of Darwin's closest associates, however, and Darwin himself, did not see it that way. In order to assess whether Darwin's version of evolutionary theory does or does not employ teleological explanation, two of his botanical studies are examined. The result of this examination is that Darwin sees selection explanations of adaptations as teleological explanations. The confusion in the nineteenth century about Darwin's attitude to teleology is argued to be a result of Darwin's teleological explanations not conforming to either of the dominant philosophical justifications of teleology at that time. Darwin's explanatory practices conform well, however, to recent defenses of the teleological character of selection explanations.I would like to thank John Beatty, David Hull and one of this journal's readers for constructive comments on an earlier draft of this paper.     

THE FIDELITY OF THE FOSSIL RECORD: THE IMPROBABILITY OF PRESERVATION

Abstract:  The fidelity of the fossil record reflects how accurately it preserves the history of life. Since Darwin's time any mismatch between our theories and the fossil record has been attributed to the imperfections of the record. For over a century scarcity of gradual evolutionary trends was explained in this way until the punctuated equilibrium model was proposed. A null hypothesis that all morphological patterns in the fossil record are unbiased random walks can be rejected because it predicts far more apparent trends than exist. Current best estimates suggest that trends occur in at most 5% of characters. When an organism dies either it becomes fossilized or it doesn't. To be confident a species has not been preserved the probability against preservation must be significantly larger than the total number of individuals of that species that ever existed. For skeletized species preservation was the norm not the exception. Nevertheless, fossils must then avoid subsequent destruction and be discovered to be useful.     

Early Miocene catarrhine dietary behaviour: the influence of the Red Queen Effect on incisor shape and curvature

The early Miocene catarrhine fossil record of East Africa represents a diverse and extensive adaptive radiation. It is well accepted that these taxa encompass a dietary range similar to extant hominoids, in addition to some potentially novel dietary behaviour. There have been numerous attempts to infer diet for these taxa from patterns of dental allometry and incisor and molar microwear, however, morphometric analyses until now have been restricted to the post-canine dentition. It has already been demonstrated that given the key functional role of the incisors in pre-processing food items prior to mastication, there is a positive correlation between diet and incisal curvature (Deane, A.S., Kremer, E.P., Begun, D.R., 2005. A new approach to quantifying anatomical curvatures using High Resolution Polynomial Curve Fitting (HR-PCF). Am. J. Phys. Anthropol. 128(3), 630-638.; Deane, A.S., 2007. Inferring dietary behaviour for Miocene hominoids: A high-resolution morphometric approach to incisal crown curvature. Ph.D. Dissertation. The University of Toronto.). This study seeks to re-examine existing dietary hypotheses for large-bodied early Miocene fossil catarrhines by contrasting the incisal curvature for these taxa with comparative models derived from prior studies of the correlation between extant hominoid incisor curvature and feeding behaviour. Incisor curvature was quantified for 78 fossil incisors representing seven genera, and the results confirm that early Miocene fossil catarrhines represent a dietary continuum ranging from more folivorous (i.e., Rangwapithecus) to more frugivorous (i.e., Proconsul) diets, as well as novel dietary behaviours that are potentially similar to extant ceboids (i.e., Afropithecus). Additionally, early Miocene fossil catarrhine incisors are less curved than extant hominoid incisors, indicating a general pattern of increasing mesio-distal and labial curvature through time. This pattern of morphological shifting is consistent with the Red Queen Effect (Van Valen, L., 1973. A new evolutionary law. Evol. Theory 1, 1-30), which predicts that taxa that are removed from one another by geological time, although potentially having similar diets, may exhibit differing degrees of a similar dietary adaptation (i.e., differing degrees of incisal curvature).     

Early twentieth-century paleontological research of Freidrich von Huene: contributions to the knowledge of Late Cretaceous vertebrates of Central Brazil

Friedrich von Huene’s important scientific research on tetrapod fossils from Central Brazil has received little attention, even though it represents a significant contribution to early studies of vertebrate paleontology in the country including the first discoveries of dinosaur fossils in Brazil. von Huene described five reptile taxa in two papers published in important German scientific journals and used these specimens to make paleogeographic inferences regarding the Cretaceous of the Southern Hemisphere. von Huene warrants recognition as the first specialist to describe in detail the fossil reptile fauna of Central Brazil, which was made possible only by his network of contacts with important and influential naturalists of the cities of Rio de Janeiro and São Paulo.     

Macroevolution is more than repeated rounds of microevolution

SUMMARY Arguments over macroevolution versus microevolution have waxed and waned through most of the twentieth century. Initially, paleontologists and other evolutionary biologists advanced a variety of non-Darwinian evolutionary processes as explanations for patterns found in the fossil record, emphasizing macroevolution as a source of morphologic novelty. Later, paleontologists, from Simpson to Gould, Stanley, and others, accepted the primacy of natural selection but argued that rapid speciation produced a discontinuity between micro- and macroevolution. This second phase emphasizes the sorting of innovations between species. Other discontinuities appear in the persistence of trends (differential success of species within clades), including species sorting, in the differential success between clades and in the origination and establishment of evolutionary novelties. These discontinuities impose a hierarchical structure to evolution and discredit any smooth extrapolation from allelic substitution to large-scale evolutionary patterns. Recent developments in comparative developmental biology suggest a need to reconsider the possibility that some macroevolutionary discontinuites may be associated with the origination of evolutionary innovation. The attractiveness of macroevolution reflects the exhaustive documentation of large-scale patterns which reveal a richness to evolution unexplained by microevolution. If the goal of evolutionary biology is to understand the history of life, rather than simply document experimental analysis of evolution, studies from paleontology, phylogenetics, developmental biology, and other fields demand the deeper view provided by macroevolution.     

Built for speed,not for comfort. Darwinian theory and human culture

Darwin believed that his theory of evolution would stand or fall on its ability to account for human behavior. No species could be an exception to his theory without imperiling the whole edifice. The ideas in the Descent of Man were widely discussed by his contemporaries although they were far from being the only evolutionary theories current in the late nineteenth century. Darwin's specific evolutionary ideas and those of his main followers had very little impact on the social sciences as they emerged as separate disciplines in the early Twentieth Century. Not until the late twentieth century were concerted, sophisticated efforts made to apply Darwinian theory to human behavior. Why such a long delay? We argue that Darwin's theory was rather modern in respects that conflicted with Victorian sensibilities and that he and his few close followers failed to influence any of the social sciences. The late Twentieth Century work takes up almost exactly where James Baldwin left off at the turn of the century.     

A bridge-builder: Wolf-Ernst Reif and the Darwinisation of German paleontology

Wolf-Ernst Reif was an outstanding German paleontologist, who, along with his empirical studies (biomechanics, functional and constructional morphology, etc.), paid significant attention to theoretical issues and the history of his discipline. Reif was a bridge-builder, skillfully synthesising history, theory and empirical studies within German-language paleontology. This paper briefly discusses sophisticated relationships between German paleontology and Darwinism based on the historical studies of Wolf-Ernst Reif. German paleontology did not fully embrace Darwinism until the 1970s. There are several reasons for this. First, alternative evolutionary theories (saltationism, neo-Lamarckism, orthogenesis) occupied a significant segment of the theoretical landscape in the German life sciences. Second, typological thinking persisted in German paleontology after the Second World War. Third, German paleontologists were relatively uninterested in discussing mechanisms of evolution, concentrating instead on reconstructing phylogenetic history.     

THE IMPACT OF REGIONAL CLIMATE ON THE EVOLUTION OF MAMMALS: A CASE STUDY USING FOSSIL HORSES

One of the classic examples of faunal turnover in the fossil record is the Miocene transition from faunas dominated by anchitheriine horses with low-crowned molar teeth to faunas with hipparionine horses characterized by high-crowned teeth. The spread of hipparionine horses is associated with increased seasonality and the expansion of open habitats. It is generally accepted that anchitheriine horses did not display an evolutionary increase in tooth crown height prior to their extinction. Nevertheless, to test whether anchitheriines showed any changes interpretable as adaptation to local conditions, we analyzed molar teeth from multiple populations of Anchitherium in three dimensions. Our results show differences in tooth morphology that suggest incipient hypsodonty in Spain, the first region experiencing increasingly arid conditions in the early Miocene of Europe. Furthermore, analyses of tooth wear show that Spanish specimens cluster with present ungulates that eat foliage together with grasses and shrubs, whereas German specimens cluster with present-day ungulates that eat mostly foliage. Taken together, even a taxon such as Anchitherium , with a long and successful history of forest adaptation, did respond to regional environmental changes in an adaptive manner.     

The evolutionary radiation of modern birds (Neornithes): reconciling molecules, morphology and the fossil record

The pattern, timing and extent of the evolutionary radiation of anatomically modern birds (Neornithes) remains contentious: dramatically different timescales for this major event in vertebrate evolution have been recovered by the 'clock-like' modelling of molecular sequence data and from evidence extracted from the known fossil record. Because current synthesis would lead us to believe that fossil and nonfossil evidence conflict with regard to the neornithine timescale, especially at its base, it is high time that available data are reconciled to determine more exactly the evolutionary radiation of modern birds. In this review we highlight current understanding of the early fossil history of Neornithes in conjunction with available phylogenetic resolution for the major extant clades, as well as recent advancements in genetic methods that have constrained time estimates for major evolutionary divergences. Although the use of molecular approaches for timing the radiation of Neornithes is emphasized, the tenet of this review remains the fossil record of the major neornithine subdivisions and better-preserved taxa. Fossils allowing clear phylogenetic constraint of taxa are central to future work in the production of accurate molecular calibrations of the neornithine evolutionary timescale.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 141 , 153–177.     

Functional morphology and evolutionary ecology

Functional morphology studies physico-chemical properties and biological roles of organs. If applied to fossils this approach is connected with specific methodological problems. The fields of application of functional morphology in paleontology are illustrated with examples. In a working concept it is shown how the results of functional morphology can be integrated into an account of the evolutionary ecology of fossil taxa.     

埃迪卡拉纪至寒武纪苗岭世刺细胞动物化石研究现状与展望

刺细胞动物是一类具有刺细胞的水生无脊椎动物,分布在世界各地的海洋和淡水中.作为后生动物最早分化出的一支,刺细胞动物对研究后生动物的起源和早期演化具有极其重要的意义,也为研究后生动物系统发育、地层对比和古地理恢复等方面提供了重要的科研线索.本文简要介绍了刺细胞动物早期(埃迪卡拉纪至寒武纪苗岭世)的化石记录和研究现状,将刺...     

Darwinism and the Origin of Life: The Role of H.C. Bastian in the British Spontaneous Generation Debates, 1868--1873

Henry Charlton Bastian's support for spontaneous generation is shown to have developed from his commitment to the new evolutionary science of Darwin, Spencer, Huxley and Tyndall. Tracing Bastian's early career development shows that he was one of the most talented rising young stars among the Darwinians in the 1860s. His argument for a logically necessary link between evolution and spontaneous generation was widely believed among those sympathetic to Darwin's ideas. Spontaneous generation implied materialism to many, however, and it had associations in Britain with radical politics and amateur science. Huxley and the X Club were trying to create a public posture of Darwinism that kept it at arm's length from those negative associations. Thus, the conflict that developed when Huxley and the X Club opposed Bastian was at least as much about factional in-fighting among the Darwinians as it was about the experiments under dispute. Huxley's strategy to defeat Bastian and define his position as “non-Darwinian” contributed significantly to the shaping of Huxley's famous address “Biogenesis and Abiogenesis.” Rhetorically separating Darwinism from Bastian was thus responsible for Huxley's first clear public statement that a naturalistic origin of life was compatible with Darwin's ideas, but only in the earth's distant past. The final separation of the discourse on the meaning of Brownian movement and “active molecules” from any possible link with spontaneous generation also grew out of Huxley's strategy to defeat Bastian. Clashes between Bastian and the X Club are described at the BAAS, the Royal Society, and in the pages of Nature and other journals. This revised version was published online in July 2006 with corrections to the Cover Date.     

The impact of the Pull of the Recent on extant elasmobranchs

Modern elasmobranchs have a long evolutionary history and an abundant fossil record that consists mainly of teeth. Many fossil taxa have living representatives. However, the representation of extant taxa in the fossil record is unknown. To begin to understand the geological history of extant elasmobranchs, we here assess the quality of their fossil record. We do so by assessing the Pull of the Recent (POR). The POR can bias the fossil record because the rather complete record of living taxa allows palaeontologists to identify fossil members of the modern clades and to bridge time bins where fossils are absent. We assessed the impact of the POR by quantifying the proportion of extant elasmobranchs that have a fossil record, but do not occur in the last 5 million years (Pliocene and Pleistocene). We found that the POR does not affect orders and families, but it does affect 24% of elasmobranch genera. Within the different elasmobranch orders, the Lamniformes display the most complete generic fossil record, with no impact of the POR. Although modest, the impact of the POR in extant elasmobranch genera is higher than that found in other taxa. Overall, the geological history of elasmobranchs contradicts the usual assumption that the fossil record becomes worse backwards in time. This is the case across geographical regions and tooth size, further suggesting that sampling intensity and outcrop availability might explain the POR effect on sharks and rays.