Patterns in the evolution of herbivory in large terrestrial mammals: the Paleogene of North America
Bibliographic record
Abstract
Introduction This chapter examines the evolution of herbivory among the larger terrestrial mammals (ungulates and ungulate-like mammals) of the Early Tertiary (Paleogene, encompassing the Paleocene, Eocene, and Oligocene epochs). There are sound reasons for examining paleoecological trends in large mammals separately from small ones, both in terms of the allometry of the ecological attributes of living mammals (see Brown 1995) and in terms of paleontological and taphonomic biases (see Fortelius et al. 1996). The term ‘herbivory’ is used to refer to diets that include primarily plant material, as opposed to animal material. In this chapter, I especially emphasize the evolution of the more restricted form of herbivory, folivory, meaning the consumption of only the fibrous, structural parts of the plants, such as stems and leaves. Folivorous mammals today include both browsers and grazers. (There were no grasslands in the Early Tertiary to support the latter dietary habit.) These mammals have some sort of symbiotic association with micro-organisms in the gut for cellulose fermentation. Folivores are usually contrasted with frugivores, that is animals that eat primarily fruit and other non-structural parts of the plant. There is also a category of ‘frugivorous/folivorous’ mammals, which take a mixture of fruit, seeds and leaves but do not select fibrous food requiring fermentation. Exclusively herbivorous mammals must be above a certain body size (approximately one kilogram) because plant material does not contain enough nutrition per unit volume to support the metabolic rate of smaller endotherms (Kay 1975). Some small (i.e., less than 1 kg in body mass) extant mammals, such as voles and other specialized rodents, can be exclusively herbivorous by virtue of being ‘granivorous,’ specialized for taking grass seeds.
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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 | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".