B4.2.8—Dentition and diet in Family Hominidae
Hominid dentition reflects diet because incisors slice, canines tear and premolars or molars grind food of different toughness in feeding.
- Syllabus
- First assessment 2025
- Objective
- B4.2.8
- Level
- SL
Tooth Shape Reveals a Food-Processing Job
| Tooth | Shape and main mechanical job |
|---|---|
| incisor | sharp edge slices or bites off pieces |
| canine | pointed crown grips and tears |
| premolar | broader surface crushes and begins grinding |
| molar | large surface grinds food repeatedly |
Dietary inference uses more than one tooth: relative tooth area, cusp shape, enamel wear, jaw robustness and muscle-attachment sites reveal the forces and movements emphasized during feeding.
Form supports a probable processing strategy, not a complete menu. Tools, cooking, ancestry and convergent evolution can weaken a simple tooth-to-diet rule.
Infer Hominid Diet from a Cluster of Skull Features
| Evidence pattern | Supported inference |
|---|---|
| gorilla: large post-canine teeth, robust jaw, large chewing muscles and sagittal crest | repeated forceful processing of tough vegetation |
| Paranthropus robustus: megadont cheek teeth, thick enamel and robust mandible | high chewing loads from tough or abrasive foods |
| human: smaller canines and molars, gracile jaw, rounded molar cusps | generalized omnivorous processing with less emphasis on forceful grinding |
Make the inference from the combined pattern, then state its limit. Tooth wear and muscle attachment strengthen a claim; one isolated feature cannot prove exactly which foods were eaten.
Summary: Build a Niche from Constraints and Interactions
A niche connects abiotic tolerance + resource acquisition + activity and form + interactions. These dimensions explain how a species survives and reproduces, not merely where it is found.
potential conditions and resources → fundamental niche
competition, predation, mutualism and dispersal → realized niche
strong overlap for a limiting resource → competition
partitioning by food, space or time → reduced overlap and possible coexistence
To explain an adaptation, name the challenge, the feature or behaviour, its physical or physiological effect, and the consequence for survival or reproduction within that niche.
Concept essentials
- Incisors slice food, while canines tear or pierce.
- Premolars and molars crush and grind food.
- Robust jaws and large grinding teeth can indicate tough plant diets.
- Human dentition is consistent with omnivory and reduced canine size.