bluuebunny/crossref_metadata_2025 huggingface dataset:
Equilibrium between Sulphuric Acid and Sulphates in Aqueous Solution
Authors: Kay Sydney A.
Published: June 2019

In the year 1847, as one of the results of an investigation to determine the part played by the mass action of water in chemical reactions, H. Rose (Pogg. Ann., lxxxii. 545) showed that an acid sulphate in aqueous solution is progressively decomposed into free acid and neutral sulphate by increasing quantities of water. His observations were confirmed and extended by the thermo-chemical researches of Thomsen (Pogg. Ann. 1869, cxxxviii. 72), and Berthelot (Ann. Chim. Phys., 1873, xxix. 433), who indicated more exactly the course and extent of this decomposition, and from whose work it is known that in the solution of an acid sulphate there exist free sulphuric acid, neutral sulphate and acid sulphate. Finally Ostwald, in his first memoir on chemical affinity (Jour, prakt. Cliem. 1879, xix. 483), showed how to determine the magnitude of this decomposition, and was able to approximately measure the quantity of free acid in solutions of the acid sulphates at different dilutions. In a later paper (ibid., 1880, xxii. 305), Ostwald investigated the question of the influence of water on the action between sulphuric acid and a neutral sulphate. He measured the changes of volume which occurred when solutions of sulphuric acid and sodium sulphate were mixed in varying proportions, and at different dilutions, and obtained results in agreement with his previous work. He also pointed out, that if the mutual action between the acid and neutral sulphate obeyed the general law of mass action, it should follow that, for example, one molecule sodium sulphate plus three molecules sulphuric acid, give the same quantity of acid sulphate as one molecule sulphuric acid, and three molecules sodium sulphate, the volume of the mixture being the same in each case.
Note on Polarisation Phenomena observed in Quantitative Electrolytic Determinations
Authors: Marshall Hugh
Published: June 2019

The phenomena to which it is desired to call attention were first observed in the course of an investigation into the electrolytic methods of determining nickel, carried out in connection with the work of the British Association Committee on the Electrolytic Methods of Quantitative Analysis. The results of the investigation are given in the Report of last year's meeting (Bristol, 1898, p. 300), but the present matter is not referred to there, as it was first noticed only during the preparation of the report.

The apparatus employed for most of the determinations consisted of the usual Classen form of cathode basins, with disc anodes. The current was drawn from storage batteries at 12 volts, variable resistances being used in the circuits. A Davies' ammeter could be introduced easily into any circuit at will, and a Davies' voltmeter was also used to indicate the difference of potential at the electrodes. These measuring instruments were so arranged and connected that the operation which introduced the ammeter into a circuit simultaneously brought the voltmeter into action; hence it happened that voltmeter readings were always taken conjointly with ammeter ones, although attention was paid almost entirely to the effects of varying the current density, and to any changes which might occur during the course of the experiment, with no special consideration of the potential involved.

For the determination of quantities of nickel varying between 0·l and 0·5 gram, the conditions adopted as most generally suitable when employing the usual method were those given below:—

Volume of solution, about 135 c.c. (giving about 100 sq. cm. of cathode area), containing 5 grams each of ammonium sulphate and of ammonia; current density at cathode (amp. per sq. decim.), 0·6–0·7; ordinary temperature; time necessary, about 4 hours.
Magnetic Twist in Nickel Tubes
Authors: Knott C. G.
Published: June 2019

(1.) Introduction.—In previous papers I have had occasion to discuss at some length the relations between Joule's discovery of the elongations accompanying magnetization in iron and Wiedemainn's discovery of the twist produced in an iron wire under the combined influence of longitudinal and circular magnetizing forces. Following out a suggestion of Maxwell's as to the intimate connection between these two phenomena, I turned my attention to nickel, in the hope of finding the Wiedemann effect in it opposite to what it is in iron in low magnetic fields. The fact that, as Barrett ‡ had shown, nickel contracted in length when longitudinally magnetized, whereas, in low fields, iron elongated wds the ground for this hope, which experiment fully justified.

In a recent paper on the strains produced in iron, steel, nickel, and cobalt tubes in the magnetic field (Trans. Boy. Soc. Edin., vol. xxxix., 1898), I have obtained, on sufficiently reasonable assumptions, values for the strain coefficients at the inner and outer walls of these tubes. Hitherto, work by other experimenters on similar lines had been on ellipsoids, rods, or wires, solid through-out. The theoretical discussion of the Wiedemann Effect (as I have called it) was rendered the more difficult on this account, and also because the current producing the circular magnetization flowed through the magnetized material. In my paper of 1888 referred to above, I make an attempt to get a formula by means of which the Wiedemann effect may be calculated from the Joule effect.
On Duplicitas Anterior in an Early Chick Embryo
Authors: Bryce Thomas H.
Published: June 2019

The literature of Duplicity in Birds affords, out of a total of about ninety-five recorded cases of multiple formations of all kinds on a single blastoderm, from the stage of the primitive streak to the fourth day of incubation, only a small proportion of instances of “duplicitas anterior.” Dareste (i.) in his atlas figures three; Gerlach (ii.) adds representations of three others—one case of his own, a second originally described by Ahlfeld, and a third by Reichert; Klaussner (iii.) gives a seventh case; and Bianchi (iv.) describes a monstrous embryo at a later stage (1°5 cm. in length).

Most observers have been content with the partial information derived from the study of the whole object, and only three embryos of this class, which have been studied in serial sections, have been described:—

1st. Erich Hoffman's (v.) with three somites.

2nd. Mitrophanow's (vi.) with six somites.

3rd. Kaestner's (vii.) with seven somites.
The Role of Interests in Science
Authors: Newton-Smith W.
Published: June 2019

A series of lectures organized in part by the Society for Applied Philosophy and entitled ‘Philosophy and Practice’ is presumably aimed at displaying the practical implications of philosophical doctrines and/or applying philosophical skills to practical questions. The topic of this paper, the role of interests in science, certainly meets the first condition. For as will be argued there are a number of theses concerning the role of interests in science which have considerable implications for how one should see the scientific enterprise in general and in particular for how one assesses the claim that science ought to be accorded its priviliged position in virtue of its results and/or methods And in view of the respect and resources accorded to science what could be of greater practical interest? It remains the case, however, that my interest may seem the inverse of that of the organizers of this series. For in looking at the role of interest in science, one is examining, so to speak, the extent to which the sphere of the practical determines what goes on in science. One is exploring ways in which the non-scientific impinges on the scientific. While my primary focus will be on the physical sciences, it will be argued that there is a significant difference between them and the social sciences; a difference which renders the social sciences intrinsically liable to penetration from outside. As will be seen, some of the particular arguments for this conclusion make pressing the question: what about philosophy? The answer, it will be concluded, is that philosophy is insulated from external influences to a considerable extent. In that lies both its importance and an explanation as to why much of it has little practical application.
Were You a Zygote?
Authors: Anscombe G. E. M.
Published: June 2019

The usual way for new cells to come into being is by division of old cells. So the zygote, which is a—new—single cell formed from two, the sperm and ovum, is an exception. Textbooks of human genetics usually say that this new cell is beginning of a new human individual. What this indicates is that they suddenly forget about identical twins.
The Rights Approach to Mental Illness
Authors: Campbell Tom
Published: June 2019

The concept of rights is now so dominant in the language of politics that it is becoming difficult to identify its use with any particular approach to the solution of social problems or to gain a clear picture of its significance, its advantages and its disadvantages as a way of conceptualizing and resolving contentious political issues. None the less there is a perceptible shift towards an emphasis on rights in contemporary politics which many welcome and encourage and others question and even reject, a shift which is matched in jurisprudence by the renewed stress which many theorists place on rights as a basic legal concept despite recurrent problems associated with the concept as a tool for legal analysis and moral justification. Conflicting theories of legal rights are canvassed and this in turn feeds into the debate concerning the reality or significance of non-legal rights, for the process of law reform is often presented as a matter of giving legal embodiment to the rights which various interested categories of people are asserted to possess already.
Child Adoption and Identity
Authors: Griffiths A. Phillips
Published: June 2019

I am concerned with a very problematic concept of identity which one encounters in studies of practical problems concerning the adoption of children. The notion is problematic in the extreme, as I shall try to show. It seems to crop up not only in the work of researchers on this topic, but in the spontaneous and (apparently) untutored accounts of themselves given by adoptees. The question is whether there is a concept here at all: by which I mean not, instead, a family of concepts linked by family resemblances, but rather some disparate ideas linked only by verbal similarities, and run together for mistaken theoretical purposes. The notion arises crucially in attempts to deal with practical questions arising in determining policies with regard to adoption: with regard to the placement of children for adoption, and the advice to be given to adoptive parents and to adopted children, whether young or adult, who encounter, or perhaps do not even encounter, difficulties.
The Marxist Ethic of Self-realization: Individuality and Community
Authors: Archard David
Published: June 2019

If, for Marx and Marxists, communism would be the most ideal of human societies, this is because it would make possible the maximum use of human and natural resources to the equal benefit of all. This means that, under communism, human beings would ‘realize themselves’. In direct and pointed contrast to capitalism wherein all individuals lead alienated, stunted, and fragmented lives, communism for Marx would provide the preconditions for a flowering, a full and final development of all human potentialities.
Abstract Morality, Concrete Cases
Authors: Clark Stephen R. L.
Published: June 2019

Practitioners of disciplines whose problems are debated by moral philosophers regularly complain that the philosophers are engaged in abstract speculation, divorced from ‘real-life’ consequences and responsibilities, that it is the practitioners (doctor, research scientist, politician) who must take the decisions, and that they cannot (and should not) act in accordance with strict abstract logic.
On Applying Ethics
Authors: Brown James M.
Published: June 2019

Applied ethics work seems to me to be of three main kinds. There is participatory work, where a person whose specialism is ethics participates in a process leading to ethical judgments or decisions. And there are two kinds of teaching work where the teaching objective is to make learners better placed to participate in such processes; one kind of teaching work relates to matters which are specific to the future occupation of the learner, the other kind relates to matters which are not specific to it.
Justice, Exploitation and the End of Morality
Authors: Ryan Alan
Published: June 2019

This paper is a small contribution to two large subjects. The first large subject is that of exploitation—what it is for somebody to be exploited, in what ways people can be and are exploited, whether exploitation necessarily involves coercion, what Marx's understanding of exploitation was and whether it was adequate: all these are issues on which I merely touch, at best. My particular concern here is to answer the two questions, whether Marx thought capitalist exploitationunjustand how the answer to that question illuminates Marx's conception of morality in general. The second large subject is that of the nature of morality—whether there are specificallymoralvalues and specifically moral forms of evaluation and criticism, how these relate to our explanatory interests in the same phenomena, what it would be like to abandon the ‘moral point of view’, whether the growth of a scientific understanding of society and ourselves inevitably undermines our confidence in the existence of moral ‘truths’. These again are issues on which I only touch if I mention them at all, but the questions I try to answer are, what does Marx propose to put in the place of moral judgment, and what kind of assessment of the horrors of capitalism does he provide if not a moral assessment?
Leisure
Authors: Telfer Elizabeth
Published: June 2019

Although the theme of these papers is ‘Contemporary Moral Problems’ my paper is partly about Aristotelian ideas. I had originally intended to apologize for this, but I find there is no need: many other contributors have found Aristotle to be timelessly relevant, as I myself have.
The Right to Work
Authors: Cullen Bernard
Published: June 2019

There is widespread agreement that the most serious and debilitating contemporary social problem in the developed capitalist world is the problem of enforced or involuntary unemployment. The growth in mass unemployment in the 1970s and 80s has produced a renewal of the demand by the labour and trade union movement1 for the implementation of a ‘right to work’; presumably in the belief that the official recognition and legal enforcement of such a right would lead to the increased availability of jobs. This campaigning slogan has sometimes emanated from the most unlikely sources. In his introduction to a published account of the 1971 Upper Clyde Shipbuilders occupation and work-in, entitledThe Right to Work, Mr Harold Wilson (then, significantly, in opposition) declared that ‘what the men of the Clyde proclaimed, and what I went to Clydeside to assert, was “the right to work”. And that principle cannot, and must not, be denied.’
Surrogacy, Liberal Individualism and the Moral Climate
Authors: Brecher Bob
Published: June 2019

I attempt in this paper to do two things: to offer some comments about recent discussions of the suggested institutionalization of surrogacy agreements; and in doing so, to draw attention to a range of considerations which liberals tend to omit from their moral assessments. The main link between these concerns is the idea that what people want is a fundamental justification (other things being equal, of course) for their getting it. I believe that this idea is profoundly mistaken; yet it is an inevitable consequence of a liberal notion of the individual and liberals' extremely limited conception of harm. My intention, then, is to illustrate how unease about a concrete problem—whether or not surrogacy agreements should be institutionalized—might interact with dissatisfaction about liberal individualism to make clearer what the unease consists in and to suggest why liberal individualism is inadequate as a basis for moral philosophy.
Genetic Engineering and the Autonomous Individual
Authors: Karin-Frank Shyli
Published: June 2019

The aim of this paper is to expose the unique muddle in which moral philosophy finds itself with regard to genetic engineering. The latter can be essentially defined as the correcting of nature's mistakes at their source, the DNA acid molecule of the gene. I shall discuss the moral nature of genetic engineering with respect to a single issue: the potential harm it may inflict upon the autonomous individual. I shall also consider the distinctions between genetic engineering and other activities affecting human existence, in order to establish that the moral issues presented by genetic engineering are unique to it.
Brain Death and Brainstem Death: Philosophical and Ethical Considerations
Authors: Lamb David
Published: June 2019

This paper examines the development of the concept of brain death and of the criteria necessary for its recognition. Competing formulations of brain death are assessed and the case for a ‘brainstem’ concept of death is argued. Attention is finally drawn to some of the ethical issues raised by the use of neurological criteria in the diagnosis of human death.
Database applications in coral research
Authors: Löser Hannes
Published: June 2019

Data on extant and fossil corals are analyzed. The characteristics of the organisms are divided into five basic units of data: morphology, ecology, taxonomical relations, stratigraphical, and (paleo-) geographical occurrence. Six data complexes are derived from these units. Their relationships are defined and the database structures designed on the basis of the Entity-Relationship-Model. The data structures are described in detail and advice is given for building up databases. The various opportunities of querying the database and particularly of assessing the data are thoroughly discussed. Data obtainable by transactions on the stratigraphical and (paleo-) geographical distribution of the organisms are considered. Finally, the database on Mesozoic corals compiled by the author is introduced and some preliminary results as well as future projects are presented.
Phylogeny and Classification: Linguliformea and Craniiformea
Authors: Holmer Lars E.
Published: June 2019

Brachiopods within the subphyla Linguliformea Williams et al., 1996 and Craniiformea Popov et al., 1993 comprise most, but not all, of the taxa previously grouped together in the Class Inarticulata Huxley, as defined in the first edition of the brachiopod volume of theTreatise on Invertebrate Paleontology(Rowell, 1965). The phylogeny and classification of the inarticulated organophosphatic-shelled linguliforms (typified by the modern lingulides; Fig. 1) and the inarticulated and partly articulated organocarbonate-shelled craniiforms (typified by the modern craniides; Fig. 1) have been debated during the last decade, in connection with attempts to analyze the phylogeny of the entire phylum (for summaries see Holmer et al., 1995; Carlson, 1995; Williams et al., 1996, 2000a). Much of the discussion has been centered around the conflicting results of phylogenetic analyses, either based exclusively on the anatomy and morphology of the Recent taxa (e.g., Popov et al., 1993; Carlson, 1991, 1995), or including also the more numerous, mainly Cambro-Ordovician, fossil taxa (e.g., Carlson, 1991; Holmer et al., 1995; Williams et al., 1996, 2000a). The cladistic analyses have either tended to support the monophyly of the Class Inarticulata (e.g., Carlson, 1991, 1995), or indicated that this group is paraphyletic (e.g., Popov et al., 1993, Holmer et al., 1995; Fig. 1). The resulting cladograms in the comprehensive studies of fossil and modern taxa by Williams et al. (1996, 2000a), which were the basis for the classification adopted in the latest edition of the brachiopod volume of theTreatise on Invertebrate Paleontology, largely support a monophyletic Subphylum Linguliformea; however, the phylogenetic position of the Craniiformea remains uncertain, although it may represent a monophyletic group (Fig. 1). Recent molecular phylogenies have given some support to a monophyletic Linguliformea, but also more surprisingly have indicated that the phoronids might form a clade (formally recognized as the Subphylum Phoroniformea Cohen 2000) within the Brachiopoda, possibly together with the inarticulated modern forms (Cohen and Gawthrop, 1996, 1997; Cohen, 2000).
The Developmental Biology of Brachiopods
Authors: Freeman Gary
Published: June 2019

The chapter on anatomy in the Treatise on Invertebrate Paleontology (Part H, Brachiopoda, revised) (Williams et al., 1997) is the most current and comprehensive treatment that we have of reproduction and development in these animals. My contribution to this short course is a commentary on and addendum to this review. The study of the developmental biology of extant brachiopods describes a large part of their life history and defines several of the parameters that have to be taken into account when thinking about how a given set of genes will make it to the next generation (Havenhand, 1995). Some extant brachiopod genera like Discinisca and Crania (Neocrania) belong to families that first appeared in the fossil record during the Lower Ordovician or, as in the case of Glottidia, to a superfamily that first appeared during the Lower Cambrian. Studies on the development of these extant animals provide a picture of what the development of their Lower Paleozoic ancestors might have been like.
Physiology
Authors: Peck Lloyd S.
Published: June 2019

Brachiopods are one of the few phyla to have lived in the world's oceans for the last 550 million years, since early Cambrian times. For much of that time they were the dominant shelled form in marine aquatic environments. Throughout all of this time their physiological structure has remained unchanged, and for some extant species their external anatomy is remarkably similar to early Cambrian forms (e.g., some inarticulated lingulids and some articulated rhynchonellides). They perform all of the basic physiological functions common to the vast majority of marine ectotherms, namely feeding, growth, reproduction, and metabolic and excretory processes. Their bodies are enclosed by two unequal shells, which are oriented dorsally and ventrally, as opposed to the lateral, equal shells in bivalve molluscs. The ventral valve in articulated species has a characteristic opening for the pedicle to pass through. In some articulated brachiopods the shells are traversed by many extensions of the mantle tissue called caeca (e.g., inWaltonia inconspicua, orTerebratulina retusa), while in others the shells form a continuous solid integument (e.g., rhynchonellides such asNotosaria nigricans). The former are the punctate brachiopods and the latter are impunctate species.
Brachiopod Shells: Recorders of the Present and Keys to the Past
Authors: Buening Nancy
Published: June 2019

The Brachiopod shell provides more than protection for the organism dwelling within: it provides a structural record of growth and a chemical record of fluctuations in the environment in which it formed. Typically, a shell formed by an accretionary process will have growth lines visible on the shell surface that can be used to measure chronological age directly. This is common in many fossil and modern bivalve molluscs where growth bands are prominent (see, e.g., Lutz and Rhoads, 1980; Jones, 1983; Tanabe, 1988). However, growth increments are not always so easily identified in other shelled organisms. For instance, growth lines in brachiopod shells are often indistinct, and the time interval represented by each growth line is uncertain. When growth information can't be obtained directly, we must turn to an alternative method (Jones and Gould, 1999). Fortunately, periodicities in the chemical composition of a shell may serve as proxies for age (e.g., Buening and Carlson, 1992). The shell chemistry of brachiopods reflects, for the most part, the changes in chemistry of the surrounding seawater. For instance, partitioning of oxygen isotopes (18O/16O ratio) in shell carbonate is sensitive to temperature (e.g., Hoefs, 1997). Thus, if brachiopods precipitate shells in water that is affected by seasonal temperature variations, then fluctuations of the18O/16O ratio of the shell should provide a record of annual temperature variation in ambient seawater. Consequently, this seasonal record may be used in conjunction with structural growth lines to reconstruct the life history of the individual, as well as the local environmental conditions in which the brachiopod lived.
New Directions in the Paleoecology of Paleozoic Brachiopods
Authors: Leighton Lindsey R.
Published: June 2019

Because of their great abundance, widespread distribution, excellent preservation potential (Foote and Sepkoski, 1999), and a tendency not to disarticulate after death, brachiopods are ideal subjects for paleoecological research involving morphometrics, population analysis, and phylogenetics. Paleoecology is a subdiscipline that demands large data sets and statistical tests, and brachiopods provide the opportunity to create such databases. I fully expect to see brachiopods play a major role in the coming years in studies on the cutting edge of paleoecology. My approach in this chapter is to provide some background and tools that hopefully will inspire many new ideas for using brachiopods in the study of paleoecology. My intent is not to convince anyone of the correctness of my ideas, but rather to encourage future research in these directions.
Originations and Extinctions in Brachiopods
Authors: Copper Paul
Published: June 2019

Broad patterns of originations and extinctions of genera, as well as families and higher groups, have always interested those who study the fossil record (e.g., Sepkoski, 1984). They record an important part of the major changeovers, and thus the dynamics, of marine ecosystems over time (Droser et al., 1996; Droser and Sheehan, 1997). This seems especially true for the Paleozoic, when brachiopods were the dominant shelly animals on the seafloor in tropical, temperate, and even cold water settings. Attempts have also been made to determine turnover patterns at the species level (Patzkowsky and Holland, 1997), though this is a much more difficult task, as the validity of species depends a great deal on the skills of the taxonomist. A similar problem is the comparative analysis of diversification data based on a single continent, e.g., North America, as related to others (Miller, 1997a, b); though Laurentia is probably better studied than most areas except western Europe. The exercise of studying broad-scale generic gains and losses for the brachiopods is at the present time preliminary (only three volumes of the revised Treatise are published). The 1965 Treatise contains fewer than 25% of the genera known in detail and described today, with an almost exponential increase in taxonomic description since the 1960s (Williams, 1996). Since then, there have been dramatic revisions and re-interpretations of the evolutionary history of the major brachiopod families, as a new generation of brachiopod workers arrived and matured. We also have a considerably improved knowledge of molecular relationships within the Brachiopoda (Cohen and Gawthrop, 1996). Sound taxonomy is the fundamental basis for sound theoretical discussion of the nature and origins of major changeovers in phyla such as the Brachiopoda. Unfortunately, there are presently relatively few, active brachiopod specialists, as taxonomy has given way to other, more general interests.
Paleobiogeography: Documenting the Ebb and Flow of Evolutionary Diversification
Authors: Brooks Daniel R. , Folinsbee Kaila E.
Published: June 2019

Historical biogeography has recently experienced a significant advancement in three integrated areas. The first is the adoption of an ontology of complexity, replacing the traditional ontology of simplicity, or a priori parsimony; simple and elegant models of the biosphere are not sufficient for explaining the geographical context of the origin of species and their post-speciation movements, producing evolutionary radiations and complex multi-species biotas. The second is the development of a powerful method for producing area cladograms from complex data, especially cases of reticulated area relationships, without loss of information. That method, called Phylogenetic Analysis for Comparing trees (PACT), is described herein. The third element is the replacement of the model of maximum vicariance with the model called the Taxon Pulse hypothesis. PACT analysis of Hominoidea, Hyaenidae, and Proboscidea beginning in the Miocene, reveals that all three groups share a general episode of species formation in Africa in the early Miocene, followed by “out of Africa” expansion into Europe, Asia and North America, a second general episode of species formation in Asia in the mid-Miocene, followed by “out of Asia” expansion into Africa, Europe and North America. Finally, there were two additional “out of Africa” events during the late Miocene and into the Pliocene, the last one setting the stage for the emergence and spread ofHomo. In addition to these shared episodes of vicariance and dispersal, each group exhibits clade-specific within-area and peripheral isolates speciation events. The complex history of dispersal and speciation over largeareas exhibited by hominoids is part of a more general historyof biotic diversification by taxon pulses.
The Application of Geographic Information Systems to Paleobiogeography: Implications for the Study of Invasions and Mass Extinctions
Authors: Rode Alycia L. Stigall
Published: June 2019

Mapping geographic ranges of species and higher taxa using Geographic Information Systems (GIS) produces quantitative data on spatial and temporal changes in geographic ranges. The primary advantage of GIS analysis is that it has the capacity to utilize large amounts of occurrence data of species to produce quantitatively constrained geographic range reconstructions that are amenable to statistical analysis. The basic steps in GIS range reconstruction are database assembly (including taxonomic, geographic, and stratigraphic information for each specimen), mapping of localities of species on modern continental configuration, rotation of occurrence data of species onto paleocontinental reconstructions, and reconstructions of geographic ranges. GIS analysis of ranges of species has been used to assess faunal dynamics of the Late Devonian Biodiversity Crisis, and three case studies are presented here. In these case studies, GIS-derived ranges of species are used to assess the relationship of biogeography with sea level, speciation and extinction rates, mass extinction survival, speciation mode, and invasive history of taxa. These case studies represent a subset of the potential for GIS analyses to examine paleontological patterns and contribute to improving understanding of the interaction between paleobiogeography, paleoecology, and evolution in the fossil record.
Quaternary Mammal Communities: Relevance of the Individualistic Response and Non-Analogue Faunas
Authors: Graham Russell W.
Published: June 2019

Frequent and repeated climate fluctuations of the late Quaternary serve as a “natural experiment” for the response of species to environmental change. Analysis of the FAUNMAP database documents individualistic shifts in the geographic distributions for late Quaternary mammals. However, because the individualistic response is not necessarily random and because many species share similar niche parameters, it is possible that some species appear to form coherent groups of core species. In reality their dispersals are individualistic with regard to rate and timing. The individualistic response of mammals, as well as that of other organisms, has created late Quaternary communities without modern analogues. This concept has profound implications for the design of biological reserves and for land use management with respect to future global climate change. However, the relevance of non-analogue mammal communities has been challenged by Alroy (1999), who claims that non-analogue associations were not common in the Quaternary and that they appeared to occur in both the Pleistocene and Holocene. Reexamination of his analysis shows that he employed a different definition for non-analogue faunas and that his methods of analyses created artificially low counts of non-analogue communities and consequently an underestimate of their importance.
The View from the Top: A Century of PS Presidents' Perspectives on the Paleontological Society and Paleontology
Authors: Kelley Patricia H.
Published: June 2019

The Paleontological Society was founded in 1908, as a section of the Geological Society of America, for the purpose of promoting the science of paleontology. Although disciplinarily inclusive, our founders were an elitist, demographically limited group. Constitutional revisions over the past century trace the evolution of the PS, including increased democratization (with a setback during the McCarthy Era, but accelerating following the turmoil of society as a whole during the 1960s), internationalization, independence from the GSA and our sister organization SEPM, and broadening of our activities and concerns. Comments by Paleontological Society presidents, in their presidential addresses and/or a survey I conducted, reinforce these conclusions. In addition, the presidential addresses demonstrate the shifting concerns and interests of paleontologists over the past century: emphasis on stratigraphic paleontology during the early years of the Society; avoidance of the topic of evolution during the antievolution movement of the 1920s – 1950s; lack of participation in the debates over continental drift; development of paleobiology. Many presidents focused on the identity of paleontology, either praising our potential for contributions to science and society or bemoaning our status and recommending remedies for our situation. Despite some predictions of impending extinction of paleontology and the PS, both our Society and our field remain vigorous as we begin our second century.
Molecular Paleobiology and the Cambrian Explosion: 21stCentury Answers to 19thCentury Problems
Authors: Peterson Kevin J.
Published: June 2019

A number of challenges face us paleontologists as we head into the 21stcentury. None is more difficult than explaining the Cambrian explosion, the dramatic differentiation of most metazoan animal phyla and classes about 545–530 million years ago. Molecular paleobiology, the experimental and theoretical integration of the geologicandthe genetic historical records of life, holds promise to help elucidate the causality of the Cambrian explosion, especially as it relates to understanding how so many animal body plans appeared in such a relatively short period of time, and why these body plans were so stable over the subsequent 500 million years. Three discoveries made over the last few years suggest that the answers to these problems might be right around the corner. First, the notion that phenotypic plasticity was higher early, as compared to later, in a clade's history has finally been confirmed and quantified for trilobites. Second, it has been shown that a recently discovered group of genes, microRNAs, regulate the precision of genic output, turning what is a fairly sloppy process (the number of transcripts derived from any genetic locus) into a precise number of protein molecules. And third, microRNAs are continuously being added to metazoan genomes, with their first major influx occurring at the base of the protostomes and deuterostomes, the very animals that so dramatically make their first appearances in the Early Cambrian. I propose that because phenotypic variation decreases through geologic time, that because miRNAs decrease genic variation in output levels, and because the number of miRNAs found within a genome increases through geologic time, miRNAs might be instrumental in the canalization of development, sacrificing phenotypic variation for developmental precision, and ultimately allowing for increases to morphological complexity. Hence, part of the solution to the Cambrian conundrum might be microRNAs, how they control development through ontogenetic time, and how they evolve through geologic time.
Evolutionary Patterns Within Fossil Lineages: Model-Based Assessment of Modes, Rates, Punctuations and Process
Authors: Hunt Gene
Published: June 2019

Patterns of phenotypic change documented in the fossil record offer the only direct view scientists have of evolutionary transitions arrayed over significant durations of time. What lessons should be drawn from these data, however, has proven to be rather contentious. Although we as paleontologists have made great progress in documenting the geological record of phenotypic evolution with greater thoroughness and sophistication, these successes have been limited by the use of verbal models of how phenotypes change. Descriptive terms such as “gradual” have been understood differently by different authors, and this has led to completely incompatible summary statements about the fossil record of morphological evolution. Here I argue that the solution to this ambiguity lies in insisting that different evolutionary interpretations be represented as explicit, statistical models of evolution. With such an approach, the powerful machinery of likelihood-based inference can be help resolve long-standing paleontological questions.

Here I first review this approach and some aspects of its implementation. Then, I show how this approach leads to new traction on important issues in evolutionary paleobiology, including: understanding modes of evolution and determining their relative importance, separating evolutionary mode from tempo, assessing the evidence for hypotheses of punctuated change, and detecting adaptive evolution in the fossil record.
Phylogenetics and the Integration of Paleontology Within the Life Sciences
Authors: Brochu Christopher A. , Sumrall Colin D.
Published: June 2019

Paleontologists rely on information from modern organisms to understand fossils, but fossils can in turn be used to more completely understand the living. This is facilitated when the fossil record is understood from a phylogenetic context. Phylogenetic analyses allow the identification of robust calibration points for molecular dating analyses, and in the absence of phylogeny, “conflicts” between fossils and molecules may arise that are based not on the data, but on methodology or taxonomic philosophy. More importantly, phylogenetic analyses using fossils can overturn evolutionary scenarios based solely on living taxa, and they can direct researchers in more appropriate directions. This is necessary if paleontology is to be fully integrated with both the Earth and life sciences.
Direct Evidence of Ancient Symbiosis Using Trace Fossils
Authors: Tapanila Leif
Published: June 2019

Symbiotic associations are a poorly studied aspect of the fossil record, owing largely to the taphonomic biases that inhibit direct observation that two organisms shared an intimate association in life. A symbiosis between an infesting animal and a skeleton-producing host can form a bioclaustration cavity that directly preserves the association and has a high preservation potential. Identification of ancient mutuals and parasites must reject the null hypothesis of commensalism by demonstrating that the symbiosis correlates with a positive or negative change in host fitness as compared to a non-symbiotic relative of the host taxon. Reviews of the Paleozoic record of marine symbionts show that the majority are hosted by colonial animals, especially corals and calcareous sponges. These hosts include structural forms that have moderate to high levels of integration and can support bioclaustrations between clonal units, mitigating the negative effects of symbionts, and perhaps facilitating the symbiosis.

The fossil record is biased toward recording long-lasting, widespread, equilibrated associations. By contrast, parasitisms that are especially negative to the host are expected to be fossilized rarely. The symbiotic associations that form bioclaustrations may also represent an endolithic adaptive strategy in response to biological antagonisms, such as predation and spatial competition. The Late Ordovician rise in symbiotic bioclaustrations joins burrows and borings as trace fossil examples of infaunalization strategies that accompany the Ordovician faunal radiation.
Neoproterozoic-Cambrian microbialite record
Authors: Shapiro Russell S.
Published: June 2019

Microbes and the sedimentary record of their activity, microbialites, have existed since the Archaean. During the Neoproterozoic-Cambrian interval, there is a marked shift in the fossil record of microbialites with the widespread proliferation of thrombolites (clotted microbialites) and the appearance and proliferation of dendrolites (microbialites composed of dendritic clusters) alongside stromatolites (laminated microbialites). Calcimicrobes also diversified during this interval. The end of this resurgence coincided with the increase in invertebrate taxa at the end of the Early Ordovician. The ìMicrobialite Resurgenceî has long been recognized but the importance of the Neoporoterozoic microbialite record for deciphering trends of this interval has not been so widely realized. It is critical to note that some of the oldest skeletal invertebrates and calcimicrobes are found in Neoproterozoic microbial reefs. Also, microbe-invertebrate synecology and invertebrate abundance trends during this interval suggests that a simple model that keys the resurgence tied in to a lack of competition from reef-building sponges and corals may not be valid. Current re-evaluation of the environmental conditions, principally the fluctuations in the geochemical conditions of the global oceans and atmosphere, will likely shed new light on understanding the Neoproterozoic-Cambrian microbialite record.
The fossil record of early eukaryotic diversification
Authors: Porter Susannah M.
Published: June 2019

The Cambrian explosion can be thought of as the culmination of a diversification of eukaryotes that had begun several hundred million years before. Eukaryotes - one of the three domains of life — originated by late Archean time, and probably underwent a long period of stem group evolution during the Paleoproterozoic Era. A suite of taxonomically resolved body fossils and biomarkers, together with estimates of acritarch and compression fossil diversity, suggest that while divergences among major eukaryotic clades or 'super-groups' may have occurred as early as latest Paleoproterozoic through Mesoproterozoic time, the main phase of eukaryotic diversification took place several hundred million years later, during the middle Neoproterozoic Era. Hypotheses for Neoproterozoic diversification must therefore explain why eukaryotic diversification is delayed several hundred million years after the origin of the eukaryotic crown group, and why diversification appears to have occurred independently within several eukaryotic super-groups at the same time. Evolutionary explanations for eukaryotic diversification (the evolution of sex; the acquisition of plastids) fail to account for these patterns, but ecological explanations (the advent of microbial predators) and environmental explanations (changes in ocean chemistry) are both consistent with them. Both ecology and environment may have played a role in triggering or at least fueling Neoproterozoic eukaryotic diversification.
Early skeletal fossils
Authors: Bengtson Stefan
Published: June 2019

The Precambrian-Cambrian transition saw the burgeoning of diverse skeletal organisms (“small shelly fossils”), represented in the fossil record by spicules, tubes, tests, conchs, shells, and a variety of sclerites and ossicles. Whereas calcareous biomineralization as such may have been facilitated by changes in ocean chemistry at this time, the utilization of biominerals in mineralized skeletons is a different process. The massive appearance of skeletons is most likely an epiphenomenon of the general radiation of body plans and tissues. The “choice” of biominerals (mainly calcium carbonates, calcium phosphates, and silica) may reflect the environmental conditions under which the particular skeleton first evolved.
Environmental patterns in the origin and diversification loci of Early Cambrian skeletalized Metazoa: Evidence from the Avalon microcontinent
Authors: Landing Ed , Westrop Stephen R.
Published: June 2019

The Cambrian Radiation was expressed as major changes in marine communities. High-diversity skeletalized metazoan faunas appeared and persisted with little change in the most proximal onshore habitats and show little expansion into the offshore through much of the long (ca. 24 m.y.) pretrilobitic Placentian Epoch on the Avalon microcontinent. These small shelly fossil communities and a large number of coelomate burrowers that appeared earlier in the Placentian comprise the Placentian Ecologic Evolutionary Unit (new)—the initial stage of the Cambrian Evolutionary Fauna. Early members of a number of high-level metazoan groups were concentrated in onshore habitats vacated by the demise of the Ediacaran fauna, where they diversified and, possibly, originated no earlier than latter part of the Placentian Epoch (543–ca. 519 (m.y.a.). Development of unstable substrates and predation in open shelf habitats occupied coelomate trace producers may have been a key factor in the restriction of diverse skeletalized metazoan faunas to peritidal habitats, where mineralized skeletons may have served as protection from desiccation and UV-damage. In contrast, the oldest trilobites are most diverse and abundant in offshore habitats, and their appearance in habitats dominated by large trace producers suggests a protective role of their mineralized integument.
Ecosystem Paleobiology and Geobiology: Connecting the Biological and Earth Systems
Authors: Bush Andrew M. , Pruss Sara B. , Payne Jonathan L.
Published: June 2019

Ecology, the study of interactions among organisms and their surroundings, can be approached on multiple scales ranging from the organism to the biosphere (Fig. 1), with unique processes governing interactions and dynamics at each scale. Individual organisms interact with their environment in many ways, including feeding, movement, and respiration. Populations are groups of individuals of a single species living in a local area, and population ecology relates to the dynamics of population size, density, and demographic structure. Communities consist of the populations living and interacting in an area; community ecologists study interactions within communities and their effects on the abundance, diversity, and distribution of species and populations. Ecosystems consist of communities of organisms plus their chemical and physical environment, and ecosystems are typically studied in terms of the movement of energy and nutrients among organisms and the environment. The biosphere encompasses all ecosystems (Fig. 1).