scholarly journals Fossils with Feathers and Philosophy of Science

2019 ◽  
Vol 68 (5) ◽  
pp. 840-851 ◽  
Author(s):  
Joyce C Havstad ◽  
N Adam Smith

AbstractThe last half century of paleornithological research has transformed the way that biologists perceive the evolutionary history of birds. This transformation has been driven, since 1969, by a series of exciting fossil discoveries combined with intense scientific debate over how best to interpret these discoveries. Ideally, as evidence accrues and results accumulate, interpretive scientific agreement forms. But this has not entirely happened in the debate over avian origins: the accumulation of scientific evidence and analyses has had some effect, but not a conclusive one, in terms of resolving the question of avian origins. Although the majority of biologists have come to accept that birds are dinosaurs, there is lingering and, in some quarters, strident opposition to this view. In order to both understand the ongoing disagreement about avian origins and generate a prediction about the future of the debate, here we use a revised model of scientific practice to assess the current and historical state of play surrounding the topic of bird evolutionary origins. Many scientists are familiar with the metascientific scholars Sir Karl Popper and Thomas Kuhn, and these are the primary figures that have been appealed to so far, in prior attempts to assess the dispute. But we demonstrate that a variation of Imre Lakatos’s model of progressive versus degenerative research programmes provides a novel and productive assessment of the debate. We establish that a refurbished Lakatosian account both explains the intractability of the dispute and predicts a likely outcome for the debate about avian origins. In short, here, we offer a metascientific tool for rationally assessing competing theories—one that allows researchers involved in seemingly intractable scientific disputes to advance their debates.

Author(s):  
Georgy S. Levit ◽  
◽  
Uwe Hossfeld ◽  

Philosophical theories proceeding from the history of physical-mathematical sciences are hardly applicable to the analysis of biosciences and evolutionary theory, in particular. This article briefly reconstructs the history of evolutionary theory beginning with its roots in the 19th century and up to the ultracontemporary concepts. Our objective is to outline the dynamics of Darwinism and anti-Darwinism from the perspective of the philosophy of science. We begin with the arguments of E. Mayr against the applicability of T. Kuhn’s theory of scientific revolutions to the history of biology. Mayr emphasized that Darwin’s publication of the Origin of Species in 1859 caused a genuine scientific revolution in biology, but it was not a Kuhnian revolution. Darwin coined several theories comprising a complex theoretical system. Mayr defined five most crucial of these theories: evolution as such, common descent of all organisms including man, gradualism, the multiplication of species explaining organic diversity, and, finally, the theory of natural selection. Distinguishing these theories is of great significance because their destiny in the history of biology substantially differed. The acceptance of one theory by the majority of the scientific community does not necessarily mean the acceptance of others. Another argument by Mayr proved that Darwin caused two scientific revolutions in biology, which Mayr referred to as the First and Second Darwinian Revolutions. The Second Darwinian Revolution happened already in the 20th century and Mayr himself was its active participant. Both revolutions followed Darwin’s concept of natural selection. The period between these two revolutions can be in no way described as “normal science” in Kuhnian terms. Our reconstruction of the history of evolutionary theory support Mayr’s anti-Kuhnian arguments. Furthermore, we claim that the “evolution of evolutionary theory” can be interpreted in terms of the modified research programmes theory by Imre Lakatos, though not in their “purity”, but rather modified and combined with certain aspects of Marxian-Hegelian dialectics.


2021 ◽  
Author(s):  
Haifeng Zhang ◽  
Renjie Shang ◽  
Kwantae Kim ◽  
Wei Zheng ◽  
Christopher J. Johnson ◽  
...  

The size of an animal is determined by the size of its musculoskeletal system. Myoblast fusion is an innovative mechanism that allows for multinucleated muscle fibers to compound the size and strength of individual mononucleated cells. However, the evolutionary history of the control mechanism underlying this important process is currently unknown. The phylum Chordata hosts closely related groups that span distinct myoblast fusion states: no fusion in cephalochordates, restricted fusion and multinucleation in tunicates, and extensive, obligatory fusion in vertebrates. To elucidate how these differences may have evolved, we studied the evolutionary origins and function of membrane-coalescing agents Myomaker and Myomixer in various groups of chordates. Here we report that Myomaker likely arose through gene duplication in the last common ancestor of tunicates and vertebrates, while Myomixer appears to have evolved de novo in early vertebrates. Functional tests revealed an unexpectedly complex evolutionary history of myoblast fusion in chordates. A pre-vertebrate phase of muscle multinucleation driven by Myomaker was followed by the later emergence of Myomixer that enables the highly efficient fusion system of vertebrates. Thus, our findings reveal the evolutionary origins of chordate-specific fusogens and illustrate how new genes can shape the emergence of novel morphogenetic traits and mechanisms.


2019 ◽  
Vol 116 (36) ◽  
pp. 17880-17889 ◽  
Author(s):  
Valentina Rossi ◽  
Maria E. McNamara ◽  
Sam M. Webb ◽  
Shosuke Ito ◽  
Kazumasa Wakamatsu

Recent discoveries of nonintegumentary melanosomes in extant and fossil amphibians offer potential insights into the physiological functions of melanin not directly related to color production, but the phylogenetic distribution and evolutionary history of these internal melanosomes has not been characterized systematically. Here, we present a holistic method to discriminate among melanized tissues by analyzing the anatomical distribution, morphology, and chemistry of melanosomes in various tissues in a phylogenetically broad sample of extant and fossil vertebrates. Our results show that internal melanosomes in all extant vertebrates analyzed have tissue-specific geometries and elemental signatures. Similar distinct populations of preserved melanosomes in phylogenetically diverse vertebrate fossils often map onto specific anatomical features. This approach also reveals the presence of various melanosome-rich internal tissues in fossils, providing a mechanism for the interpretation of the internal anatomy of ancient vertebrates. Collectively, these data indicate that vertebrate melanins share fundamental physiological roles in homeostasis via the scavenging and sequestering of metals and suggest that intimate links between melanin and metal metabolism in vertebrates have deep evolutionary origins.


2017 ◽  
Author(s):  
Christopher A. Emerling

AbstractRegressive evolution of anatomical traits corresponds with the regression of genomic loci underlying such characters. As such, studying patterns of gene loss can be instrumental in addressing questions of gene function, resolving conflicting results from anatomical studies, and understanding the evolutionary history of clades. The origin of snakes coincided with the regression of a number of anatomical traits, including limbs, taste buds and the visual system. By studying the genomes of snakes, I was able to test three hypotheses associated with the regression of these features. The first concerns two keratins that are putatively specific to claws. Both genes that encode these keratins were pseudogenized/deleted in snake genomes, providing additional evidence of claw- specificity. The second hypothesis is whether snakes lack taste buds, an issue complicated by unequivocal, conflicting results in the literature. I found evidence that different snakes have lost one or more taste receptors, but all snakes examined retained at least some capacity for taste. The final hypothesis I addressed is that the earliest snakes were adapted to a dim light niche. I found evidence of deleted and pseudogenized genes with light- associated functions in snakes, demonstrating a pattern of gene loss similar to other historically nocturnal clades. Together these data also provide some bearing on the ecological origins of snakes, including molecular dating estimates that suggest dim light adaptation preceded the loss of limbs.


Human Studies ◽  
2019 ◽  
Vol 43 (1) ◽  
pp. 61-87 ◽  
Author(s):  
Hub Zwart

Abstract Gaston Bachelard (1884–1962) occupies a unique position in the history of European thinking. As a philosopher of science, he developed a profound interest in genres of the imagination, notably poetry and novels. While emphatically acknowledging the strength, precision and reliability of scientific knowledge compared to every-day experience, he saw literary phantasies as important supplementary sources of insight. Although he significantly influenced authors such as Lacan, Althusser, Foucault and others, while some of his key concepts (“epistemological rupture,” “epistemological obstacle,” “technoscience”) are still widely used, his oeuvre tends to be overlooked. And yet, as I will argue, Bachelard’s extended series of books opens up an intriguing perspective on contemporary science. First, I will point to a remarkable duality that runs through Bachelard’s oeuvre. His philosophy of science consists of two sub-oeuvres: a psychoanalysis of technoscience, complemented by a poetics of elementary imagination. I will point out how these two branches deal with complementary themes: technoscientific artefacts and literary fictions, two realms of human experience separated by an epistemological rupture. Whereas Bachelard’s work initially entails a panegyric in praise of scientific practice, he becomes increasingly intrigued by the imaginary and its basic images (“archetypes”), such as the Mother Earth archetype.


2020 ◽  
Vol 131 (1) ◽  
pp. 61-75
Author(s):  
Christoph Abel ◽  
Jutta M Schneider ◽  
Matjaž Kuntner ◽  
Danilo Harms

Abstract Few spider species show truly cosmopolitan distributions. Among them is the banded garden spider Argiope trifasciata, which is reported from six continents across major climatic gradients and geographical boundaries. In orb-weaver spiders, such global distributions might be a result of lively dispersal via ballooning. However, wide distributions might also be artefactual, owing to our limited understanding of species taxonomy. To test the hypothesis that A. trifasciata might be a complex of cryptic species with more limited geographical ranges, we investigated the biogeographical structure and evolutionary history of A. trifasciata through a combination of time-calibrated phylogenetic analyses (57 terminals and three genes), ancestral range reconstruction and species delimitation methods. Our results strongly suggest that A. trifasciata as currently defined is not a single species. Its populations fall into five reciprocally monophyletic clades that are genetically distinct and have evolutionary origins in the Plio-Pleistocene. These clades are confined to East Asia, temperate Australia, Hawaii, the New World and the Old World (Africa and most of the Palaearctic). Our results provide the basis for future investigation of morphological and/or ecological disparity between the populations that are likely to represent species, in addition to examinations of the attributes and dispersal modes of these species.


2018 ◽  
Vol 61 (4) ◽  
pp. 69-103
Author(s):  
Nebojsa Lukic

Even though Thomas Kuhn was a physicist by formal education, he is better known for his achievements in philosophy of science than in science itself. He was primarily concerned with history of science and subjects such as development of science, growth of scientific knowledge, changes in science and others. In that sense Kuhn was focused on giving the correct description of scientific reality in human history, that is, on giving the description of the most relevant elements of scientific research. Kuhn claims that scientists base their research on paradigms which are the key factor in scientific practice overall. All other concepts of Kuhn?s philosophy - such as, for instance, normal science, revolutionary science, incommensurability of paradigms - gain their meaning in relation to the concept of a paradigm. However, the concept of a paradigm in its original definition was very problematic, which, later on, led Kuhn to make its meaning more precise. Hence, the task of this paper is to illuminate the nature of that central concept i.e. to determine the essential features of a paradigm in relation to the rest of the conceptual network of Kuhn?s theory, and therefore its role in science and in that conceptual network. At the same time, the meaning of all those elements of Kuhnian science which are in direct relation to the paradigm will be illuminated. I will restrict my research on early and transitional period of Kuhn?s creatorship, and I base this distinction on Sankey?s analysis. The difference between these two periods is determined by Kuhn?s thinking about the formulation of the thesis of incommensurability of paradigms. Accordingly, it is necessary to deal with definition of incommensurability, its division to types and Kuhn?s view on implications of incommensurability for science and its progress.


Author(s):  
Wendy Parker

Arguments in environmental ethics often appeal to information from environmental science, such as information about the causes of environmental problems. Contemporary work in philosophy of science can shed light on the practice of environmental science as well as some of the challenges it faces. This chapter surveys some of this work, focusing on three interrelated topics: the nature of scientific evidence, including connections with uncertainty and consensus; the use and evaluation of scientific models; and values and objectivity in scientific practice. A better understanding of these topics can help to ensure that scientific information is used appropriately and effectively in ethical argumentation.


2021 ◽  
Vol 22 (12) ◽  
pp. 6348
Author(s):  
Dongmei Liang ◽  
Weiguo Li ◽  
Xiaoguang Yan ◽  
Qinggele Caiyin ◽  
Guangrong Zhao ◽  
...  

Sesquiterpenes are important defense and signal molecules for plants to adapt to the environment, cope with stress, and communicate with the outside world, and their evolutionary history is closely related to physiological functions. In this study, the information of plant sesquiterpene synthases (STSs) with identified functions were collected and sorted to form a dataset containing about 500 members. The phylogeny of spermatophyte functional STSs was constructed based on the structural comparative analysis to reveal the sequence–structure–function relationships. We propose the evolutionary history of plant sesquiterpene skeletons, from chain structure to small rings, followed by large rings for the first time and put forward a more detailed function-driven hypothesis. Then, the evolutionary origins and history of spermatophyte STSs are also discussed. In addition, three newly identified STSs CaSTS2, CaSTS3, and CaSTS4 were analyzed in this functional evolutionary system, and their germacrene D products were consistent with the functional prediction. This demonstrates an application of the structure-based phylogeny in predicting STS function. This work will help us to understand evolutionary patterns and dynamics of plant sesquiterpenes and STSs and screen or design STSs with specific product profiles as functional elements for synthetic biology application.


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