scholarly journals Does time matter in phylogeny? A perspective from the fossil record

2021 ◽  
Author(s):  
Pauline Guenser ◽  
Rachel C. M. Warnock ◽  
Philip Conrad James Donoghue ◽  
Emilia Jarochowska
Keyword(s):  
Bayesian Inference ◽  
Fossil Record ◽  
Phylogenetic Inference ◽  
Late Devonian ◽  
Tree Inference ◽  
Phylogenetic Hypotheses ◽  
Range Process ◽  
Flexible Models ◽  
Intense Debate

The role of time (i.e. taxa ages) in phylogeny has been a source of intense debate within palaeontology for decades and has not yet been resolved fully. The fossilised birth-death range process is a model that explicitly accounts for information about species through time. It presents a fresh opportunity to examine the role of stratigraphic data in phylogenetic inference of fossil taxa. Here, we apply this model in a Bayesian framework to an exemplar dataset of well-dated conodonts from the Late Devonian. We compare the results to those obtained using traditional unconstrained tree inference. We show that the combined analysis of morphology and stratigraphic data under the FBD range process reduces overall phylogenetic uncertainty, compared to unconstrained tree inference. We find that previous phylogenetic hypotheses based on parsimony and stratophenetics are closer to trees generated under the FBD range process. However, the results also highlight that irrespective of the inclusion of age data, a large amount of topological uncertainty will remain. Bayesian inference provides the most intuitive way to represent the uncertainty inherent in fossil datasets and new flexible models increase opportunities to refine hypotheses in palaeobiology.

Phylogenetic Analysis and its Application in Evolutionary Paleobiology

1991 ◽  
Vol 4 ◽  
pp. 103-122 ◽  
Author(s):  
Daniel C. Fisher
Keyword(s):  
Phylogenetic Analysis ◽  
Fossil Record ◽  
Phylogenetic Inference ◽  
Short Course ◽  
Unique Constraint ◽  
Service Role ◽  
History Of ◽  
Knowledge Of Evolution ◽  
Final Synthesis

Each of the perspectives on the fossil record represented by contributions to this short course (and many that are not) can claim a legitimate share of the mantle of “Analytical Paleontology,” earned by combining rigor and insight to provide some unique constraint on our understanding of the history of life. Dare I claim more for phylogeny? Certainly not, if “more” suggests that phylogeny is some final synthesis, complete unto itself, sought by all, and needing no further justification. Such a posture would make phylogenetic inference an end in itself, and, although it may sometimes appear that phylogeneticists have this in mind, I will argue here that it is the service role of phylogenetic analysis that makes it important in shaping our knowledge of evolution. Interpretation of the phylogenetic relationships of the organisms we study has profound implications for virtually all of our other ways of handling data from the fossil (or Recent) record.

scholarly journals The first iguanian lizard from the Mesozoic of Africa

2016 ◽  
Vol 3 (9) ◽  
pp. 160462 ◽  
Author(s):  
Sebastián Apesteguía ◽  
Juan D. Daza ◽  
Tiago R. Simões ◽  
Jean Claude Rage
Keyword(s):  
New Species ◽  
Bayesian Inference ◽  
Late Cretaceous ◽  
Fossil Record ◽  
New Taxon ◽  
Biogeographic History ◽  
Lower Jaw ◽  
Tree Inference ◽  
Inference Methods ◽  
Multiple Tree

The fossil record shows that iguanian lizards were widely distributed during the Late Cretaceous. However, the biogeographic history and early evolution of one of its most diverse and peculiar clades (acrodontans) remain poorly known. Here, we present the first Mesozoic acrodontan from Africa, which also represents the oldest iguanian lizard from that continent. The new taxon comes from the Kem Kem Beds in Morocco (Cenomanian, Late Cretaceous) and is based on a partial lower jaw. The new taxon presents a number of features that are found only among acrodontan lizards and shares greatest similarities with uromastycines, specifically. In a combined evidence phylogenetic dataset comprehensive of all major acrodontan lineages using multiple tree inference methods (traditional and implied weighting maximum-parsimony, and Bayesian inference), we found support for the placement of the new species within uromastycines, along with Gueragama sulamericana (Late Cretaceous of Brazil). The new fossil supports the previously hypothesized widespread geographical distribution of acrodontans in Gondwana during the Mesozoic. Additionally, it provides the first fossil evidence of uromastycines in the Cretaceous, and the ancestry of acrodontan iguanians in Africa.

scholarly journals Phanerozoic p O 2 and the early evolution of terrestrial animals

2018 ◽  
Vol 285 (1871) ◽  
pp. 20172631 ◽  
Author(s):  
Sandra R. Schachat ◽  
Conrad C. Labandeira ◽  
Matthew R. Saltzman ◽  
Bradley D. Cramer ◽  
Jonathan L. Payne ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Fossil Record ◽  
Insect Flight ◽  
Late Devonian ◽  
Low Oxygen ◽  
Physiological Constraint ◽  
Fossil Records ◽  
Physiological Suppression ◽  
Bashkirian Stage

Concurrent gaps in the Late Devonian/Mississippian fossil records of insects and tetrapods (i.e. Romer's Gap) have been attributed to physiological suppression by low atmospheric p O 2 . Here, updated stable isotope inputs inform a reconstruction of Phanerozoic oxygen levels that contradicts the low oxygen hypothesis (and contradicts the purported role of oxygen in the evolution of gigantic insects during the late Palaeozoic), but reconciles isotope-based calculations with other proxies, like charcoal. Furthermore, statistical analysis demonstrates that the gap between the first Devonian insect and earliest diverse insect assemblages of the Pennsylvanian (Bashkirian Stage) requires no special explanation if insects were neither diverse nor abundant prior to the evolution of wings. Rather than tracking physiological constraint, the fossil record may accurately record the transformative evolutionary impact of insect flight.

scholarly journals Free will and neurosurgical resections of the supplementary motor area: a critical review

2021 ◽  
Vol 163 (5) ◽  
pp. 1229-1237 ◽  
Author(s):  
Rickard L Sjöberg
Keyword(s):  
Executive Function ◽  
Free Will ◽  
Corticospinal Tract ◽  
Supplementary Motor Area ◽  
Personal Responsibility ◽  
Motor Area ◽  
Simple Motor ◽  
Motor Actions ◽  
Intense Debate

Abstract Background Research suggests that unconscious activity in the supplementary motor area (SMA) precedes not only certain simple motor actions but also the point at which we become aware of our intention to perform such actions. The extent to which these findings have implications for our understanding of the concepts of free will and personal responsibility has been subject of intense debate during the latest four decades. Methods This research is discussed in relation to effects of neurosurgical removal of the SMA in a narrative review. Results Removal of the SMA typically causes a transient inability to perform non-stimulus-driven, voluntary actions. This condition, known as the SMA syndrome, does not appear to be associated with a loss of sense of volition but with a profound disruption of executive function/cognitive control. Conclusions The role of the SMA may be to serve as a gateway between the corticospinal tract and systems for executive function. Such systems are typically seen as tools for conscious decisions. What is known about effects of SMA resections would thus seem to suggest a view that is compatible with concepts of personal responsibility. However, the philosophical question whether free will exists cannot be definitely resolved on the basis of these observations.

scholarly journals Labor Standards: Where Do They Belong on the International Trade Agenda?

2001 ◽  
Vol 15 (3) ◽  
pp. 89-112 ◽  
Author(s):  
Drusilla K Brown
Keyword(s):  
Developing Countries ◽  
International Trade ◽  
Labor Standards ◽  
Labor Regulation ◽  
National Sovereignty ◽  
The Past ◽  
Trade Sanctions ◽  
Technical Advice ◽  
Intense Debate

During the past decade, universal labor standards have become the focus of intense debate. Advocates argue from humanitarian concerns and the interests of industrialized-country labor, seeking enforcement with WTO sanctions. Opponents regard labor regulation as a matter of national sovereignty, challenge the effectiveness of trade sanctions, and prefer the ILO emphasis on dialogue, monitoring and technical advice. This paper analyzes the labor standards debate, with specific attention to the analytical underpinnings of universal rules; evidence linking weak labor protections in developing countries to industrialized country wages; and the role of labor standards in WTO negotiations.

scholarly journals An abundance of developmental anomalies and abnormalities in Pleistocene people

2018 ◽  
Vol 115 (47) ◽  
pp. 11941-11946 ◽  
Author(s):  
Erik Trinkaus
Keyword(s):  
Fossil Record ◽  
Elevated Level ◽  
Developmental Disorders ◽  
Upper Paleolithic ◽  
Developmental Changes ◽  
Single Factor ◽  
Developmental Abnormalities ◽  
Low Probability ◽  
Developmental Variants

Diverse developmental abnormalities and anomalous features are evident in the PleistoceneHomofossil record, varying from minor but rare dental, vertebral, and carpal variants to exceptional systemic disorders. There are currently 75 documented anomalies or abnormalities from 66 individuals, spanning the Pleistocene but primarily from the Late Pleistocene Middle and Upper Paleolithic with their more complete skeletal remains. The expected probabilities of finding these variants or developmental disorders vary from <5% to <0.0001%, based on either recent human incidences or relevant Pleistocene sample distributions. Given the modest sample sizes available for the skeletal or dental elements in question, especially if the samples are appropriately limited in time and geography, the cumulative multiplicative probability of finding these developmental changes is vanishingly small. These data raise questions regarding social survival abilities, differing mortuary treatments of the biologically unusual, the role of ubiquitous stress among these Pleistocene foragers, and their levels of consanguinity. No single factor sufficiently accounts for the elevated level of these developmental variants or the low probability of finding them in the available paleontological record.

scholarly journals The origin and early radiation of terrestrial vertebrates

2001 ◽  
Vol 75 (6) ◽  
pp. 1202-1213 ◽  
Author(s):  
Robert L. Carroll
Keyword(s):  
Fossil Record ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Lower Carboniferous ◽  
Major Transitions ◽  
Terrestrial Vertebrates ◽  
History Of ◽  
Paleozoic Tetrapods ◽  
Early Radiation ◽  
Ways Of Life

The origin of tetrapods from sarcopterygian fish in the Late Devonian is one of the best known major transitions in the history of vertebrates. Unfortunately, extensive gaps in the fossil record of the Lower Carboniferous and Triassic make it very difficult to establish the nature of relationships among Paleozoic tetrapods, or their specific affinities with modern amphibians. The major lineages of Paleozoic labyrinthodonts and lepospondyls are not adequately known until after a 20–30 m.y. gap in the Early Carboniferous fossil record, by which time they were highly divergent in anatomy, ways of life, and patterns of development. An even wider temporal and morphological gap separates modern amphibians from any plausible Permo-Carboniferous ancestors. The oldest known caecilian shows numerous synapomorphies with the lepospondyl microsaur Rhynchonkos. Adult anatomy and patterns of development in frogs and salamanders support their origin from different families of dissorophoid labyrinthodonts. The ancestry of amniotes apparently lies among very early anthracosaurs.

Hybrid crinoids in the fossil record (Early Mississippian, Phylum Echinodermata)

Paleobiology ◽  
1994 ◽  
Vol 20 (3) ◽  
pp. 362-367 ◽  
Author(s):  
William I. Ausich ◽  
David L. Meyer
Keyword(s):  
Fossil Record ◽  
Evolutionary Process ◽  
Parent Species ◽  
Probable Explanation ◽  
South Central ◽  
Most Probable Explanation ◽  
The Impact

Potential hybrid fossil crinoids, Eretmocrinus magnificus x Eretmocrinus praegravis, are identified from the Lower Mississippian Fort Payne Formation of south-central Kentucky. These are the first fossil hybrid crinoids identified, and one of very few examples of hybrids recognized in the fossil record. Eretmocrinus magnificus x E. praegravis specimens have shapes and calyx plate sculpturing that are morphologically intermediate between well-defined, distinct parent species. Suspected hybrids occur at localities where parent species co-occur and where the parent species are the most abundant; the hybrids occur at what may have been the distributional margins of the parent species; and the mixture of characters on suspected hybrids seems to be morphogenetically partitioned. Parent species are derived from separate lineages within Eretmocrinus, and hybridization is the most probable explanation for these morphologically intermediate specimens. This example highlights the need to consider hybridization as a potential interpretation of intermediate morphologies among fossils and raises questions concerning the impact of hybridization for our interpretation of the fossil record and the role of hybridization in the evolutionary process.

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