scholarly journals Nonequilibrium evolution of volatility in origination and extinction explains fat-tailed fluctuations in Phanerozoic biodiversity

2019 ◽  
Vol 5 (6) ◽  
pp. eaat0122 ◽  
Author(s):  
Andrew J. Rominger ◽  
Miguel A. Fuentes ◽  
Pablo A. Marquet
Keyword(s):  
Fossil Record ◽  
Statistical Physics ◽  
Marine Invertebrate ◽  
Statistical Equilibrium ◽  
Niche Conservatism ◽  
Entire System ◽  
Nonequilibrium Statistical Physics ◽  
Adaptive Landscapes

Fluctuations in biodiversity, large and small, pervade the fossil record, yet we do not understand the processes generating them. Here, we extend theory from nonequilibrium statistical physics to describe the fat-tailed form of fluctuations in Phanerozoic marine invertebrate richness. Using this theory, known as superstatistics, we show that heterogeneous rates of origination and extinction between clades and conserved rates within clades account for this fat-tailed form. We identify orders and families as the taxonomic levels at which clades experience interclade heterogeneity and within-clade homogeneity of rates, indicating that families are subsystems in local statistical equilibrium, while the entire system is not. The separation of timescales between within-clade background rates and the origin of major innovations producing new orders and families allows within-clade dynamics to reach equilibrium, while between-clade dynamics do not. The distribution of different dynamics across clades is consistent with niche conservatism and pulsed exploration of adaptive landscapes.

scholarly journals More Than Names: The role of updated taxonomy in palaeontology collections

2019 ◽  
Vol 3 ◽  
Author(s):  
Ricardo Paredes
Keyword(s):  
Fossil Record ◽  
Marine Invertebrate ◽  
Research Community ◽  
Type Material ◽  
Museum Collections ◽  
Web Based ◽  
2D Imaging ◽  
Visual Impact ◽  
Fossil Data

The accuracy on taxonomic determinations of palaeontology collections may have significant consequences in estimations of organism diversity through time. This justifies the need of taxonomic standardization of palaeontological collections. The perception of palaeodiversity through Phanerozoic time has significantly improved since the Sepkoski showed the marine invertebrate taxonomic data in diversity graphs, organized in orders (Sepkoski 1978) and families (Sepkoski 1979, Sepkoski 1984). The visual impact of these graphs engaged palaeontologists into gathering quantitative macroevolution in order to better understand marine palaeodiversity. Alroy et al. (2008) presented a rebuilt diversity curve based on genus-level in a large sample record. These and other statistically sound and standardized datasets of fossil occurrences have combined sources as literature, databases, and museum collections data as a foundation. Integration of these datasets with the entire fossil record based on individual specimens in space and time would be the ideal approach to species-level taxonomy standards determinations. An example showing how this approach may be achieved is the use of initiatives such as the Web-based data facility Palaeontology Database (PdB) which includes a large amount of fossil record data from throughout the world. The major advantage of that is to gather institucional and also private palaeontological collections with taxonomy experts validation. The core of these datasets is the taxon, with the species as the expected most reliable unit. Taxonomy is therefore the discipline enrolled in the process with the taxonomist at the centre of the process. Updated taxonomy is crucial to create reliable datasets and a careful approach should prevent biased data due to under- or overestimation of diversity. Palaeontological museum collections are known to be one of the largest repositories of fossil data. Taxonomic standardization of palaeontology collections in the context of a museum should: Engage taxonomists in revising fossil clades of the museum material; Promote networking and museum researcher peers involved in similar collections activities; Avoid replication of errors in taxonomic determinations (e.g. exclusive use of Web-based databases sources of taxonomy); Use type material to compare with the collection specimens; Critically analyse previous taxonomic determinations on old labels and associated specimen information; Promote the accessibility of the collection to the research community; Emphasize digitisation of specimen catalogue records as well as 2D imaging of the specimens. Engage taxonomists in revising fossil clades of the museum material; Promote networking and museum researcher peers involved in similar collections activities; Avoid replication of errors in taxonomic determinations (e.g. exclusive use of Web-based databases sources of taxonomy); Use type material to compare with the collection specimens; Critically analyse previous taxonomic determinations on old labels and associated specimen information; Promote the accessibility of the collection to the research community; Emphasize digitisation of specimen catalogue records as well as 2D imaging of the specimens. These practices are valuable complements to current methodologies adopted to improve the taxonomy of collections, resulting in more reliable data which further enables museum-based research focusing on palaeodiversity estimations.

Reefs as the Centralizing Theme in an Undergraduate Invertebrate Paleontology Course

2012 ◽  
Vol 12 ◽  
pp. 21-42
Author(s):  
Constance M. Soja
Keyword(s):  
Fossil Record ◽  
Evolutionary History ◽  
Marine Invertebrate ◽  
Scientific Information ◽  
Field Trip ◽  
Mass Extinctions ◽  
Paleontological Data ◽  
San Salvador ◽  
Invertebrate Paleontology ◽  
The Impact

This course is designed so that topics in invertebrate paleontology are discussed in the context of reefs and their change through time. The goal is to help undergraduate students connect modern conservation issues with an enlightened appreciation of the fossil record. Using reefs as the centralizing theme of the course allows key concepts (invertebrate taxonomy and systematics, form and function, evolution, etc.) to be emphasized while exploring the importance of biogenic buildups—and communities that inhabited ecosystems adjacent to those “engines of evolution”—from the past to the present. Students who satisfactorily complete the course achieve seven main learning objectives: They 1) are intimately familiar with the fossil record of marine invertebrate life; 2) understand the evolutionary history of reefs and the ecological roles played by key reef-building invertebrates through time; 3) are able to engage in discussions about paleontological data published in the primary literature; 4) are knowledgeable about the value of paleontological evidence for shedding insights into the decline of ancient and living reefs; 5) gain experience working collaboratively and thinking outside-of-the-box to explore solutions to societal problems linked with the degradation of modern coral reefs; 6) improve scientific writing; and 7) develop a personal style for communicating scientific information to the general public. During classroom discussions, laboratories, a field trip, and museum visit, students explore the anatomy, ecology, evolutionary history, and life-sustaining ecosystem services of shelly animals and associated marine organisms that coexisted in reefs and adjacent habitats past and present. Evolutionary events, including the Cambrian “explosion,” mass extinctions, and gaps in reef existence, are linked to dramatic physical (tectonic) and climatic changes that occurred in Earth's past. Emphasizing evidence for the impact of global change on ancient reef communities alerts students to the value of paleontological data for predicting how modern reefs—and invertebrates living in interconnected marine ecosystems—will respond as the Sixth Extinction gains traction. That topic is the focus of an optional extended study (nine-day field trip offered in alternate years during spring break) of modern and Pleistocene reefs on San Salvador Island, Bahamas.

scholarly journals Spectral analysis for a class of integral-difference operators: known facts, new results, and open problems

2004 ◽  
Vol 2004 (1) ◽  
pp. 221-249 ◽  
Author(s):  
Yuri B. Melnikov
Keyword(s):  
Spectral Analysis ◽  
Present State ◽  
Statistical Physics ◽  
State Of The Art ◽  
Difference Operators ◽  
Open Problems ◽  
Nonequilibrium Statistical Physics

We present state of the art, the new results, and discuss open problems in the field of spectral analysis for a class of integral-difference operators appearing in some nonequilibrium statistical physics models as collision operators. The author dedicates this work to the memory of Professor Ilya Prigogine, who initiated this activity in 1997 and whose interesting and most enlightening advices had gudided the author during all these years.

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