Human Evolution Bone Quiz

Arboreal adaptations

Opposable thumbs and big toes, nails instead of claws

Aboreal adaptations - enhanced vision

forward facing eyes (increased depth perception)

Primate Teeth

primitive mouth with 4 distinct kinds of teeth:

1. incisors

2. canines

3. premolars

4. molars

Tarsier dental formula

Upper: 2/1/3/3

Lower: 1/1/3/3

Lemur dental formula

Upper: 2/1/3/3/

Lower: 2/1/3/3 (sometimes this varies in lemurs)

New World Monkey dental formula

Upper: 2/1/3/2 or 2/1/3/3

Lower: 2/1/3/2 or 2/1/3/3

Old World Monkey dental formula

Upper: 2/1/2/3

Lower: 2/1/2/3

Apes and Human dental formula

Upper: 2/1/2/3

Lower: 2/1/2/3

Monkey tooth variation

bilophodont (two-ridge tooth) molar

Ape and Human tooth variation

Y-5 lower molars

Lemur, Lorise, and Galago tooth variation

dental comb (lower incisors and canines are elongated, crowded together, and projected forward)

Prosimians

Smaller brain than monkeys, mostly nocturnal (large eye sockets), tooth combs, grooming claw. Includes:

• Lemurs

• Lorises

• Galagos

• Tarsiers

Anthropoids

Larger brains than prosimians. Includes:

• New world monkeys

• Old world monkeys

• Apes

• Humans

Hominoids

• Apes

• Humans

Dryopithecus

Extinct genus of great ape during Miocene epoch, 14-9 mya, France and Spain

Sivapithecus

extinct genus of great ape during miocene epoch, 14-8 mya, Asia

Oreopithecus

extinct great ape during miocene epoch, 9-7 mya, Italy

Trends in Hominin evolutions

• bipedal walking

• non honing chewing

• increased brain size

• decreases tooth size (especially molars)

Anatomy of Bipedalism

Foot:

• arch

• big toe aligns with other

Pelvis:

• basin shaped with short illium

• legs to side

Legs:

• femurs angled inwards

• offset facets at knew

• knees lock in extended position

• long in relation to arms

Spine:

• S-shaped, lumar curve

Skull:

• foramen magnum faces downward

Foramen magnum

opening for the spinal cord and other vital parts; humans exhibit a straight downward orientation

Nonhoning chewing

grinding or food, rather than shearing (honing); wear on the tip for canine

Sahelanthropus tchadensis

small brain (350cc), bipedal (foramen magnum), non honing chewing and small canines, massive browridge

Ardipithecus kadabba (Ardi)

• bipedal based on toe bones

• perihoning complex

• hand and arm bones indicate partial arboreal adaptation

Ardipithecus ramidus

• small brain (350cc)

• bipedal based on foramen magnum, pelvis, femur, and foot

• non honing canines

• mix of climbing and walking adaptations

Australopithecus anamensis

• bipedal based on shin bone

• arms and hands adapted to tree climbing

• non honing canines (larger than humans, smaller than apes)

• parallel rows of teeth

Australopithecus afarensis (Lucy)

• cranial capacity 430cc

• large premolars and molars (adaptation to tough fibrous plants, seeds, and nuts)

• small, fragile hyoid bone (no language)

• bipedal based on skull, pelvis, tibia, and ankle

Australopithecus gahri (Gracile)

• small brain (450cc)

• large teeth (premolars and molars)

• forward-projecting face

• curved phalanges (toes)

• long legs (human like)

Robust Australopithecines - Hypervegetarians

Variety of derived features that suggest a diet of hard, tough plant foods

• sagittal crest (a prominent ridge of bone running lengthwise along the top of the skull)

• massive cheekbones

• large palate

• massive molars

• thick enamel

Australopithecus aethiopicus

• small brain (410cc)

• massive posterior teeth

• robust skull with sagittal crest (a prominent ridge of bone running lengthwise along the top of the skull)

Australopithecus boisei

• small brain (510cc)

• massive posterior teeth

• robust skull with sagittal crest

Australopithecus africanus

• small brain (450cc)

• small, non honing canines; large premolars and molars; parabolic jaw (the curved, V-shaped arrangement of teeth in modern humans)

• straight phalanges (fingers)

• bipedal

Australopithecus sediba

• small brain (420cc)

• small teeth

• human-like face, hands, and pelvis

• primitive ape-like foot

Australopithecus robustus

• small brain (530cc)

• small, non honing canines; very large premolars and molars

• robust skull with sagittal crest

Homo habilis

• large brain (600cc)

• smaller teeth (indicative of dietary shift - more generalized)

• Australopithecus-like body

  • < 4 ft tall

  • long arms and short legs

Homo erectus

• larger and more robust than Homo habilis

• longer legs - body proportions similar similar to modern humans

• larger brain (950cc)

• classic cranial features:

  • low forehead

  • pronounced browridge

  • large anterior teeth

  • small back teeth

  • sagittal keel

  • occipital torus (a thickened, horizontal band of bone on the occipital bone at the back of the skull, often appearing as a prominent ridge or bump)

  • pentagonal rear view

• shovel shaped incisors

• classic features more pronounced in Asian examples

Homo naledi

• small brain (464-610cc)

• body smaller than modern humans

• human-like features include hands, feet, and legs

• shoulders positioned for climbing

• curved fingers

• small teeth

Homo sapien (modern humans)

• large brain size (1300-1500cc)

• rounded skull with high forehead

• small face and jaw

• reduced brow ridge

• flat face with less projection

Classic Neanderthal cranial features

• occipital bun

• long, flat, low brain case (>1400cc)

• reduced forehead

• brow ridge

• large nasal cavity

• projecting midface

• circular orbitals

• little or no chin (mental eminence

• large gap behind third molar

Neanderthal cold adaptations

• large nasal aperture (heat the air)

• large infraorbital foramina (hold in check that allows blood flow to face)

• stocky body (this reduced surface area relative to body size reduces heat loss)

• short limbs (reduces surface area to reduce heat loss)