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The time-sensitivity and predictability of echinoderm disarticulation makes them model organisms to determine post-mortem transportation and allows recognition of ecological-time data within paleocommunity accumulations. The patterns present in crinoids and echinoids can be used to develop a more thorough understanding of all echinoderm clades.
"This Element reviews the ecologies of skeletal trace-producing interactions on echinoids in modern ecosystems and the recognition of those biogenic traces in the fossil record. This title is also available as Open Access on Cambridge Core"--
The echinoderms are an ideal group to understand evolution from a holistic, interdisciplinary framework. The genetic regulatory networks underpinning development in echinoderms are some of the best known for any model group. Additionally, the echinoderms have an excellent fossil record, elucidating in in detail the evolutionary changes underpinning morphological evolution. In this Element, the echinoderms are discussed as a model group for molecular palaeobiological studies, integrating what is known of their development, genomes, and fossil record. Together, these insights shed light on the molecular and morphological evolution underpinning the vast biodiversity of echinoderms, and the animal kingdom more generally.
Echinoderms have evolved diverse and disparate morphologies throughout the Phanerozoic. Among them, blastozoans, an extinct group of echinoderms that were an important component of Paleozoic marine ecosystems, are primarily subdivided into groups based on the morphology of respiratory structures. However, systematic and phylogenetic research from the past few decades have shown that respiratory structures in blastozoans are not group-defining and they have re-evolved throughout echinoderm evolution. This Element provides a review of the research involving blastozoan respiratory structures, along with research concerning the morphology, paleoecology, and ontogeny of each of the major groupings of blastozoans as it relates to their corresponding respiratory structures. Areas of future research in these groups are also highlighted.
Placing evolutionary events in the context of geological time is a fundamental goal in paleobiology and macroevolution. In this Element we describe the tripartite model used for Bayesian estimation of time calibrated phylogenetic trees. The model can be readily separated into its component models: the substitution model, the clock model and the tree model. We provide an overview of the most widely used models for each component and highlight the advantages of implementing the tripartite model within a Bayesian framework.
Computational fluid dynamics (CFD), which involves using computers to simulate fluid flow, is emerging as a powerful approach for elucidating the palaeobiology of ancient organisms. Here, Imran A. Rahman describes its applications for studying fossil echinoderms.
Echinoderms elaborate a calcite skeleton composed of numerous plates with a distinct microstructure (stereom) that can be modelled into different shapes thanks to the use of a transient amorphous calcium carbonate (ACC) precursor phase and the incorporation of an intraorganic matrix during biomineralization. A variety of different types of stereom microarchitecture have been distinguished, each of them optimized for a specific function. For instance, a regular, galleried stereom typically houses collagenous ligaments, whereas an irregular, fine labyrinthic stereom commonly bears muscles. Epithelial tissues, in turn, are usually associated with coarse and dense stereom microfabrics. Stereom can be preserved in fossil echinoderms and a wide array of investigating methods are available. As many case studies have shown, a great deal of important paleobiological and paleoecological information can be decoded by studying the stereom microstructure of extinct echinoderms.
The quantification of morphology through time is a vital tool in elucidating macroevolutionary patterns. Studies of disparity require intense effort but can provide insights beyond those gained using other methodologies. Over the last several decades, studies of disparity have proliferated, often using echinoderms as a model organism. Echinoderms have been used to study the methodology of disparity analyses and potential biases as well as documenting the morphological patterns observed in clades through time. Combining morphological studies with phylogenetic analyses or other disparate data sets allows for the testing of detailed and far-reaching evolutionary hypotheses.
Imaging and visualizing fossils in three dimensions with tomography is a powerful approach in paleontology. Here, the authors introduce select destructive and non-destructive tomographic techniques that are routinely applied to fossils and review how this work has improved our understanding of the anatomy, function, taphonomy, and phylogeny of fossil echinoderms. Building on this, this Element discusses how new imaging and computational methods have great promise for addressing long-standing paleobiological questions. Future efforts to improve the accessibility of the data underlying this work will be key for realizing the potential of this virtual world of paleontology.
Recent advances in statistical approaches called phylogenetic comparative methods (PCMs) have provided paleontologists with a powerful set of analytical tools for investigating evolutionary tempo and mode in fossil lineages. However, attempts to integrate PCMs with fossil data often present workers with practical challenges or unfamiliar literature. This Element presents guides to the theory behind and the application of PCMs with fossil taxa. Based on an empirical dataset of Paleozoic crinoids, example analyses are presented to illustrate common applications of PCMs to fossil data, including investigating patterns of correlated trait evolution and macroevolutionary models of morphological change. The authors emphasize the importance of accounting for sources of uncertainty and discuss how to evaluate model fit and adequacy. Finally, the authors discuss several promising methods for modeling heterogeneous evolutionary dynamics with fossil phylogenies. Integrating phylogeny-based approaches with the fossil record provides a rigorous, quantitative perspective on understanding key patterns in the history of life.
Fossil crinoids are exceptionally suited to deep-time studies of community paleoecology and niche partitioning. By merging ecomorphological trait and phylogenetic data, this Element summarizes niche occupation and community paleoecology of crinoids from the Bromide fauna of Oklahoma (Sandbian, Upper Ordovician). Patterns of community structure and niche evolution are evaluated over a ~5 million-year period through comparison with the Brechin Lagerstatte (Katian, Upper Ordovician). The authors establish filtration fan density, food size selectivity, and body size as major axes defining niche differentiation, and niche occupation is strongly controlled by phylogeny. Ecological strategies were relatively static over the study interval at high taxonomic scales, but niche differentiation and specialization increased in most subclades. Changes in disparity and species richness indicate the transition between the early-middle Paleozoic Crinoid Evolutionary Faunas was already underway by the Katian due to ecological drivers and was not triggered by the Late Ordovician mass extinction.
This Element provides insight into using Instagram as a science education platform by pioneering a set of calculated metrics, using a paleontology-focused account as a case study. The authors conducted year-long analyses of 455 posts and 139 stories that were created as part of an informal science learning project.
An ontogenetic series of Deltasuchus motherali helps clarify its niche and resolve a contested part of the crocodyliform family tree.
This Element provides a hypothesis-driven look at testing models for diversification in Cambrian echinoderms, fitting and using a joint tree and diversification model to estimate a dated phylogeny of the Cincta (Echinodermata).
The diversity crisis in paleontology refers not to modern biota or the fossil record, but rather how our discipline lacks significant representation of individuals varying in race, ethnicity, and other aspects of identity. This Element is a call to action for broadening participation through improved classroom approaches.
The principles of stratigraphic paleobiology can be readily applied to the continental fossil record. From these principles, stratigraphic paleobiology can be used to make various predictions. Few studies have addressed most of these predictions, making stratigraphic paleobiology of continental systems a promising area of investigation.
This Element includes time-lapse video made in 1983 on film, followed by recent digital videography from submersibles and remotely operated vehicles of deep-sea crinoids, revealing behaviors in taxa never before seen in life.
Students' passion for dinosaurs can be harnessed to trigger interest in science and be used to develop critical thinking skills. Three methods for developing critical thought are outlined in this Element: using dinosaur paleontology to illustrate logical fallacies and flawed arguments, evaluating primary dinosaur literature, and critiquing dinosaur documentaries.
Active learning is a natural fit for paleontology, which can provide opportunities for examining fossils, analyzing data and writing. This Element introduces different types of active learning approaches and explains how these can be applied to large introductory paleontology classes for non-majors.
'Big data' science initiatives, such as the Paleobiology Database (PBDB), provide inexpensive and accessible research opportunities for undergraduate courses. This Element provides an introduction to what the PBDB is, how to use it, how it can be deployed in introductory and advanced courses, and examples of how it has been used in undergraduate research.
In this Element best practices in experiential learning are illustrated by courses with embedded student research. Guidelines are presented for how to plan and execute a student research project. Research-based teaching provides challenges for students and faculty, but the benefits for all stakeholders are strong.
The Neotoma Paleoecology Database provides support to educators from primary schools to graduate students. Collaborations among pedagogic experts, technical experts and data stewards, centered around data resources such as Neotoma, provide an important role within research communities, and an important service to society.
Discusses the theory behind kinesthetic learning and how it fits into a student-centered, active-learning paleontology classroom. Presents methods for incorporating it into student exercises. Assessment data demonstrates that these exercises have led to significantly improved student learning outcomes tied to these concepts.
Student-centered learning shifts the power and attention in a classroom from the instructor to the students. This Element provides an overview of the research on student-centered pedagogy in introductory geoscience and paleontology courses and gives examples of these instructional approaches.
This Element outlines the use of Macrostrat and its mobile client Rockd, and provides examples of how to integrate these resources into a variety of paleontology and Earth science courses. These tools provide a unique educational opportunity for students to interact with primary geological data and make new field observations.
Evidence shows that active learning helps students strengthen learning and build more advanced skills. The flipped classroom is one approach to maximize time for active learning. This Element explores a number of ways lecturers can create a flipped classroom learning environment.
Prior conceptions that include erroneous or incomplete understanding represent a barrier to durable learning. By intentionally eliciting prior conceptions and implementing pedagogical strategies described in other Elements in this series, lecturers can shape instruction to challenge negative views of paleontology and improve student learning.
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