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Record W2495218746 · doi:10.1017/cbo9780511549717.007

Dental constraints in the early evolution of mammalian herbivory

2000· book-chapter· en· W2495218746 on OpenAlexaff
John M. Rensberger

Bibliographic record

VenueCambridge University Press eBooks · 2000
Typebook-chapter
Languageen
FieldEarth and Planetary Sciences
TopicEvolution and Paleontology Studies
Canadian institutionsRoyal Ontario Museum
Fundersnot available
KeywordsHerbivoreEvolutionary biologyBiologyEcology

Abstract

fetched live from OpenAlex

Introduction The processing of plant food in mammals requires specialized mechanisms in order to sustain high rates of nutrient assimilation, and the evolution of herbivory in mammals can potentially be traced by examining changes in these structures. Conditions suitable for the preservation of soft tissues are exceedingly rare (Schaal and Ziegler 1993), and thus we cannot hope to trace the evolution of herbivory using structures of the stomach and intestinal tract. However, oral comminution of plant material is a nearly universal behavior among mammalian herbivores, owing to the problem of breaking down the plant cell walls composed of cellulose (Janis and Fortelius 1988). Fortunately, dental structures specialized for this purpose are well represented in the fossil record. One major group of Mesozoic mammals, the multituberculates, had already acquired masticatory mechanisms allowing herbivory (Hahn 1971; Krause 1982). However, the main mammalian radiation that led to modern herbivores probably occurred immediately following the extinction of the non-avian dinosaurs at the end of the Cretaceous. That event must have opened many niches that previously had been inaccessible to mammals, judging from the high taxonomic and morphological rates of evolution across the Cretaceous–Paleocene boundary (Sloan 1987). This chapter examines the functional changes in the shapes of teeth in the two dominant groups of early Paleocene ungulates in North America, compares these with common Eocene ungulates, and considers the influence that tissue strength had on the directions of these changes. The results indicate that the changes were non-linear, apparently because of mechanical constraints that had to be overcome before the more efficient mastication characteristic of modern ungulates emerged.

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.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.001
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.005
Threshold uncertainty score0.018

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.001
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0000.002
Scholarly communication0.0010.001
Open science0.0010.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0050.001

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 head0.018
GPT teacher head0.182
Teacher spread0.164 · 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

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations7
Published2000
Admission routes1
Has abstractyes

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