Dietary tolerance and the advent of meat eating Flashcards
what is the general primate diet?
- mostly omnivores with generalised dentition
- have preferences
- most eat combinations of fruit, leaves and insects
- meat eaters - chimps, gorillas, baboons
- some are leaf specialists (colobine monkey)
how are we as a species becoming more and more unhealthy?
generally - lack of exercise and increase in consumption of unhealthy foods with little nutritional value
how are hominin diets reconstructed?
craniodental morphology
isotopic study
dental microwear analyses
how do we reconstruct hominin diets using craniodental morphology
-head and teeth morphologies
- Morphological features such as thin/thick enamel, small/large teeth, tooth shape, muscle attachment site and size, overall cranial size and shape can give one an idea of what and early hominin species was designed to eat
–not always good as other factors may have also influenced food eaten - availability
-
how do we reconstruct hominin diets using stable isotopes?
- “you are what you eat”
- stable isotopes of food stuffs can become incorporated into the growing teeth and bones
- these tissues then acquire isotopic composition related to that of the source food that can reveal much about the diets
- carbon isotopes are commonly used
how do we reconstruct hominin diets by studying dental microwear?
-Mammals show a strong and consistent association between dental microwear
pattern and food fracture properties.
- Those that crush hard, brittle foods (e.g., nuts, bones) typically have occlusal microwear dominated by pits, whereas those that shear tough items (e.g., leaves, meat) more often show long, parallel striations on their wear surfaces.
- These pits and scratches are traces of actual chewing events; they record activities during a moment in the life of an individual, much like footprints.
meat eating amongst primates?
- meat from vertebrates is rarely eaten by primates
- humans and chimps eat significant amounts of meat
describe the start of meat eating in early hominins
- First dominated by large quantities of plant matter
- tooth morphology and dental microwear suggests harder foods eaten as well
- 2.6 mya expansion in diet - meat and marrow
- possible evidence of hominin butchered bones at 3.39 years but little evidence and evidence is disrupted
what is some evidence for meat eating?
- butchery marks found on bones
- hominin teeth marks found on bones
what are cut marks on animal bones caused by?
slicing of meat off bone
what are percussion marks caused by?
pounding a bone with a large stone to break it open and extract the marrow inside
where was the first evidence of meat eating found?
Gona, Ethiopia (2.6 mya), earliest documentation of stone tools
describe the earliest well documented evidence of persistent hominin carnivort?
from in situ excavated fossil fauna occuring with large concentrations of stone tools
- 2.0 mya Kanjera Kenya
evidence of consumption of aquatic animals?
evidence at Koobi Fora
foods: turtles, crocodiles and fish
about 1.95 mya
which hominins were the first systematic consumers of meat?
- Aus africanus, aus garhi and paranthropus aethiopicus 2.6-2.5 mya
- africanus and aethiopicus = no butchered bones in sites = less likely
- garhi but only in homo do we see biological features often linked to meat eating
why did hominins begin to eat meat and marrow?
- calorie dense with essential amino acids and micronutrients
- aquatic fauna provided nutrients required for brain growth
- Increasing the consumption of animal foods could have assisted hominins in increasing their body and brain size without losing mobility, agility, or sociality.
describe the technological ‘feedback loop’
stone tools = meat could be processed and then consumed = brainsize increased = more complex tools = more meat could be processed and then consumed
evidence for the first uses of fire
- origins of fire associated with the cooking of meat
- 790kya = burnt seeds, wood, flint
- earlier traces of fire = eastern and southern africa : not widely accepted - swartkrans, koobi and chesowania (sediment discoloration)
how did hominins access meat and marrow?
hunting
scavenging
explain hunting in the context of the early hominins
earliest evidence of hunting tech - 500kya - hand crafted spears
complex projectiles - 71kya
when did the hunting of larger animals begin
- hunting big animals = advanced tech needed - started with heidelbergensis
what is persistence hunting?
running down one’s prey
type of hunting possible without advanced tech
persistence running - difficult to recognise in the archaeological record
what are some hunting signatures?
cut marks, no carnivore gnaw marks
explain scavenging in the context of early hominins
Given that the earliest evidence for the use of hunting technology is relatively recent, hominins probably obtained most of their meat, especially from larger animals, via scavenging carnivore kills.
what are some signatures of scavenging?
cut marks over carnivore gnaw marks
what are disadvantages of a carnivorous way of life?
competition with other and more powerful carnivores e.g. lions, leopards
what was another result of looking for meat?
becoming the prey of other carnivores
- evidence: skulls with predator marks in them
