Hominin Features Flashcards
Australopithecus afarensis
- erect
- bipedal
- relatively long forelimb (ape-like)
- sexually dimorphism (chimp like)
- small brains (chimp like)
- intermediate teeth (pre-canine diastema, reduced canine, thicker enamel)
- neck down: more like a human
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Paranthropus robustus
- more robustly built (masticatory apparatus)
- small incisors
- reduced canines
- massive cheek teeth
- sagittal crest for attachment of temporalis muscle
Homo rudolfensis
- face size reduced
- smaller teeth
Homo habilis
- face size reduced
- smaller teeth
- thinner enamel
- Oldowan tool use
Homo erectus
- used fire
- Oldowan tools
- dead end group
Homo ergaster
- fully terrestrial bipedal
- longer developmental period (later molar eruption) - Nariokatome Boy
- First wave of migration
- Acheulian tools, fire, hunted large animals
Homo heidelbergensis
- Second wave of migration
- Acheulian tools, fire, hunted large animals
Homo neanderthalensis
- large and elongated skull
- occipital bun
- supraorbital torus
- brain slightly larger than modern humans
- large nose (as air is breathed in it is warmed before entering the lungs - cold climate)
Homo sapien
- chin
- third wave of migration out of Africa ,
What is a morphological trait used to distinguish between humans and apes?
Diastema present in chimps
What is a diastema?
Space between the upper canine and incisor that accommodates the lower canine
What is brachiation?
Method of movement that uses ams to swing from branch to branch
What anatomical features are associated with brachiation?
- long arms
- relatively short legs
- long, slender fingers
- great mobility in joints
Chimp anatomical traits
- hindlimbs shorter than forelimbs
- long pelvis
- knuckle walking (forelimbs bear weight when walking quadrupedally)
- protruding face
- posterior foramen magnum
Evolution of hominidae themes
- locomotion
- diet
- brain
Evolution of hominidae themes - diet
- shifted to a harder, more fibrous diet
- thin to thick enamel
- reduced canines
- reduced prognathism (change in dental arcade)
Evolution of hominidae themes - locomotion
- cooling, drying climate
- expansion of savannahs
Evolution of hominidae themes - brain
- cranial capacity increased (long after bipedal locomotion)
Reasons for bipedality
- feeding from trees
- thermoregulatory
- metabolically cheaper than quadrupedalism
- carrying objects
Australopithecus afarensis lower body
- pelvis broad and narrow
- femoral neck long
- femur slants inwards
Obstetrical dilemma
- human pelvis is bowl shaped to adapt for bipedality but restricts the size of the birth canal
- dramatic increase in brain size after becoming bipedal created a problem
Obstetrical dilemma: maternal adaptions
- increase in size of female pelvis resulting in sexual dimorphism of the human pelvis
- softening of pubic symphysis at the end of the pregnancy under the influence of oestrogens so that the bones can move further apart
Obstetrical dilemma: neonate adaptions
- bones of the neonatal cranium are not fused which allows compression during birth
What is prognathism?
Condition in which the part of the face below the nose is pushed out
