Diet Flashcards
Are primates herbivores?
What is a key feature of primate diet
• Primate omnivory: large number of plant food and small number of animal resources.
Flexibility: switching to novel food sources.
What is a food repertoire
preferred food and occasional food (fallback food during food shortage)
What is hard food
What are USOs?
Hard food: food items resistant to plastic deformation (nuts and seeds). • Underground storage organ (USO): root, bulb, rhizome, storage of energy and water
What does food quality refer to?
What are high quality foods?
What type of food do fallback foods tend to be
Food quality: nutrient density (high- or low-quality food)
meat, nuts and USOs.
low in energy foods
What do the following refer to:
Foraging strategies
Food processing
Foraging strategies: how to obtain food. • Food processing: how to access food (e.g., oral processing, manual processing).
What is Kleiber’s Law?
an animal’s metabolic rate scales to the 3⁄4 power of the animal’s mass.
therefore, there is an
allometric relationship body mass/BMR
How is LHS related to food quality
Could be related to the r/K selection theory: predictable environments with
abundant food resources would favor K-selected species (large-bodied
individuals, long maturation, few offspring, long lifespan ≠ r-selected species)
How would folivory be reflected in digestive anatomy
diet of leaves requires large intestines and fermentation
What is the expensive tissue hypothesis briefly
who came up with it
why is diet related
The expensive tissue hypothesis (Aiello & Wheeler, 1995): less energy to the gut, more energy to the brain, same BMR. • Possible if easy-to-digest food consumed.
Define ecological niche
Ecological niche: species interactions within an ecosystem (biotic and abiotic
factors).
Give 2 different types of speciation
Sympatric speciation: competition for resources. • Ecological speciation: ecological factor (e.g., environmental change)
responsible of the formation of a new species as a result of adaptations to a
new ecological niche
define sympatric speciation
Sympatric speciation occurs when there are no physical barriers preventing any members of a species from mating with another, and all members are in close proximity to one another. A new species, perhaps based on a different food source or characteristic, seems to develop spontaneously
What does Paranthropus’ morphology suggest about its diet
Large, thickly enameled postcanine teeth, extended zygomatic bones and bony crests (powerful muscles of mastication).
• Craniodental features suggest that it could generate and dissipate high bite forces: consumption of hard food items (e.g., nuts, seeds, hard fruits)?
Do dietary changes only have implication on the cranium (4)
No
• Locomotion and posture: feeding positions, access to resources
(ecomorphology).
• Home range area (habitats).
• Meat consumption: technological innovations.
• Social behaviour: conspecific care.
Give an example of conspecific care in hominins
the edentulous specimen of early Homo (~1.7mya) from Dmanisi - Would require sharing of food etc from rest of group
advanced alveolar bone atrophy indicates substantial tooth loss several years before death as a result of ageing and/or pathology
What does diet reveal about social behaviours (not edentulous Homo from Dmanisi)
Give key references
Parental care and ontogeny: age at weaning and integration of solid food.
• Extended growth and development: maternal energetical costs.
• Dietary stresses may cause extended period of weaning (Joannes-Boyau et al., 2019).
• The grandmother hypothesis: greater longevitiy, foraged food sharing (Hawkes et al., 1998)
Give key features of dental morphological changes between folivores, hard-food-eaters, and frugivores
- Folivores: tall shearing crests.
- Hard-object feeder: low cusps and large teeth.
- Frugivores: intermediate, large basins.
When did Australopithecines wean their young
extended baby consuming mother’s milk bc there is reduced food sources around - age of weaning directly related to environment
What is dental topography
What parameters are used
Dental topography: aspects of tooth geometry. • Parameters: how much the tooth surface differs from a flat surface (RFI), surface curvature (DNE), tooth complexity (OPC)…
What is important about thick enamel
longer lifetime, resistant to abrasive and tough food
What is important about enamel distribution
reflects the stress dissipation pattern.
How does the ‘hardness’ of foods in a diet affect enamel distribution
soft - thin enamel with an even distribution
medium - thin enamel with an uneven distribution
hard- thick enamel with uneven distribution
What is an enamel hypoplasia
surface defect of the tooth crown that is caused by a disturbance of enamel matrix secretion (lines, pits, grooves).
often caused by Physiological stress (nutritional stress or disease during the development. )
What is the wear pattern of a tooth
Wear pattern: cumulative loss of enamel (and dentine) due to friction of hard(e.g., seeds) and abrasive (e.g., phytoliths in plants, minerals) food objects.
• Reflect feeding behaviour.
Were enamel hypoplasias common in australopithecines?
yes - indicates periods of starvation and environmental stress
How can we compare the feeding biomechanics of ancient hominins?
What has this revealed
Finite element analysis: simulation of a physical phenomenon using numerical
techniques
• Morphology of Paranthropus was very good at dissipating mechanical stress (much better than Australopithecus) - Smith (2015) showed this by comparing strain during molar biting in STS5 and OH5
What is important about cut marks on bones
evidence of tool-assisted consumption of meat
o What aniimals are present in the assemblage - o Were they hunting younger animals bc its easier - revealing about subsistence strategies
How can Isotopes be used to investigate fossil hominin diet
Carbon in tooth enamel: variations of carbon isotopes (δ13C) reflect isotopic composition of the plants and animal protein eaten.
• Strontium, barium and calcium: low Ba/Ca in carnivores, high Sr/Ca in grazers, related to the composition of the substrate.
What can we infer about Ardi. ramidus’ diet
diet dominated by C3
food similar to extant chimpanzees (forest/woodland feeding).
Thin enamel in Ardipithecus ramidus: no hard objects consummed.
How did A. anamensis’ diet relate to ramidus
How did this relate to Kenyanthropus’ diet?
Australopithecus anamensis, derived nearly all of its diet from C3 resources - similar to ramidus
ubsequently, by ca. 3.3 Ma, the later Kenyanthropus platyops had a very wide dietary range—from virtually a purely C3 resource-based diet to one dominated by C4 resources
What did the diet of Homo look like 2mya and how did this relate to P boisei
65/35 ratio of C3- to C4-based resources, whereas P. boisei had a higher fraction of C4-based diet (ca. 25/75 ratio).
Homo sp. increased the fraction of C4-based resources in the diet through ca. 1.5 Ma, whereas P. boisei maintained its high dependency on C4-derived resources.
Describe the Australopithecus teeth morphology
What did microwear analysis reveal
flat, blunt molars without shearing crests, suitable for processing hard brittle objects (nuts, fruits) and soft food, but no seeds or meat.
• Thick enamel: resits breakage during the consumption of hard objects.
• Microwear analyses indicate longer scratches and few pits: feeding on fruits and some abrasive material (phytoliths?)
increase in diet breadth, increased home range?
What does Isotope analyses (13C, Sr/Ca and Ba/CA) of Australopithecus teeth indicate? (4)
high C4
consumers (nearly close to the grass eating baboons),
→ consumption of USOs,
→ variability, thus highly flexible and opportunistic diet that includes frugivory and hard food (adaptations to fallback foods?).
elemental signatures and hypoplasias indicate seasonal dietary stress
What does boisei’s cranium suggest about its diet
Isotope analyses of Paranthropus teeth: 13C-enriched foods (80% of C4
foods in P. boisei).
• Feeding biomechanics in Paranthropus: high bite forces, face well suited to withstand those loads.
Compare briefly diet of robustus and boisei (2)
→ isotopic analyses: no overlap, unique diet in P. boisei,
→ microwear analyses: P. boisei leaf based diet (more similar to baboons?) and no hard objects, P. robustus much similar to savanna generalists and hard object feeders.
What is the e hypothesis of isotopic niche?
Was the Australopithecus broad diet split into Paranthropus and Homo with
lower diversity of food? (Balter et al., 2012) • Was the early Homo diet broad (i.e., omnivorous and opportunistic
preferences) and Paranthropus specialized on hard food?
Who was first hominin to eat meat?
Earliest evidence of tool-assisted consumption of meat: >3.4 Ma (Dikika) or at
least at 2.5 Ma (Gona). - maybe afarensis?
leaves question of when did diet Shift from intermittent to more frequent meat consumption and exploitation of megafauna
What are the temporal trends in diet and morphology in hominin evolution (4)
Molar size increase: tough and abrasive diets.
• Small anterior teeth: no food preparation.
• Thick mandibular bodies: can resist extreme stresses.
• Early hominins: hard and soft foods, abrasive and nonabrasive food
What does the isotope analysis suggest about the dietary shifts in hominin evolution
Two major dietary shifts: early hominins (broader diet) and Homo (high-quality
food).
• Isotope analyses: from C3 (Au. anamensis and Ardipithecus) to C3 /C4 (Au. afarensis) to C4 (Paranthropus) and C3 /C4 (Homo) diets in eastern Africa.
Related to environment that is changing?
Why is hominin anterior dentition interesting
• Apes can use these anterior teeth to access different parts of the food – not needed when we can prep before entering mouth
Give evidence australopiths may have eaten meat
lesions observed in the vertebral elements L4 andL5 of Australopithecus africanus Stw 431 seem to be more consistent with the pathological condition of early brucellosis
seen in modern zebra and impala
given chimps occasionally eat meat - not implausible
table carbon isotope analysis of A. africanus
from Makapansgat Limeworks, South Africa, that suggest a diet based not only on fruit and leaves, but also on large quantities of carbon-13-enriched foods such as grasses and sedges or animals that ate these plants, or both
What is the benefit of decreased prognathism in Paranthropus
jaw has greater muscular advantage
BUT
comes at a cost of tooth surface area and the size
of objects that fit in the mouth.
P. boisei solves the problem of tooth area by increasing the relative size of the teeth.
How does africanus differ from afarensis (3)
africanus has higher and shorter and rounder braincase, that rarely shows sagittal cresting and that never shows compound temporo-nuchal cresting.
The nasal aperture is bordered by prominent anterior pillars and the zygomatic bone shows bossing at the transition to the temporal process.
subnasal prognathism
