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Silurian trilobite alpha diversity and the end-Ordovician mass extinction

2000· article· en· W2032223644 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

VenuePaleobiology · 2000
Typearticle
Languageen
FieldEarth and Planetary Sciences
TopicPaleontology and Stratigraphy of Fossils
Canadian institutionsUniversity of Alberta
Fundersnot available
KeywordsTrilobiteOrdovicianExtinction eventExtinction (optical mineralogy)PaleontologyLaurentiaGamma diversityCladeSpecies richnessAlpha diversityGeologyPaleozoicEcologyDiversity (politics)Beta diversityGeographyBiologyPhylogeneticsBiological dispersalDemography

Abstract

fetched live from OpenAlex

Following the end-Ordovician extinction, global clade diversity of Silurian trilobites dropped to about half of Ordovician levels. Although clade diversity failed to recover, this extinction had surprisingly little long-term impact on the number of trilobite species that occupied local habitats (alpha diversity). A new compilation of data from Laurentia and other continents indicates that Silurian trilobite alpha diversities in all major environments were comparable to those of the Late Cambrian and Ordovician; shallow subtidal diversity reached an all-time high during the Late Ordovician. The profound differences in patterns at local and global levels demonstrate the necessity for a hierarchical approach to analyses of diversity. Factors governing global clade diversity are lodged at hierarchical levels beyond those controlling local species richness and must be sought in studies of between-habitat (beta) or geographic (gamma) diversity.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.264
Threshold uncertainty score0.998

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0010.001
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0030.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.012
GPT teacher head0.194
Teacher spread0.182 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it