Origin and evolution of the grazing guild in Cenozoic New World terrestrial mammals
Bibliographic record
Abstract
Introduction Today grasslands cover about 25% of the world's land surface and constitute an enormous food resource that is exploited by invertebrate and vertebrate grazers. Grazers are defined as herbivores with diets consisting predominantly (>90%) of grass and other associated low ground cover in grassland biomes (Janis and Ehrhardt 1988). In present-day ecosystems, grazing is a common-place feeding strategy. Although terrestrial herbivory can be documented in vertebrates over the past 300 million years since the Carboniferous (Sues and Reisz 1998; Reisz and Sues, this volume), the origin of the grazing guild in vertebrates is a relatively recent arrival on the global ecological landscape. This chapter presents paleontological evidence that terrestrial grazing guilds have only existed since the middle Tertiary, about 35 million years ago. I will confine my discussion here to mammals because: (1) although in terms of biomass and diversity, invertebrate grazers (mostly insects) are potentially the largest component of terrestrial grazing guilds worldwide (Dyer et al . 1982), the fossil record of this group is relatively poor; and (2) extinct mammalian grazers generally have an exceedingly rich fossil record that can be used to understand the evolution of the grazing guild. Furthermore, recent studies of extinct mammalian grazers combine a diverse array of traditional morphological evidence along with some new techniques, including stable isotopic analyses. Together these techniques allow a better understanding of the origin and evolution of the grazing guild. This chapter will focus attention on the fossil record in the New World; however, the pattern described here also is generally applicable to the Old World.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".