Lab Practical 2 Flashcards
sexual dimorphism
difference in size/shape between sexes of the same species
what are the exaggerated features of male primates?
- larger body size
- larger canines
- more robust
high dimorphism
polygyny/high male-male competition for mates
low dimorphism
monogamy/low male-male competition for mates
shoulder morphology
- apes have flexible shoulder joints for climbing through trees
- quadrupedal monkeys have more restricted shoulder joints
- scapula placement impacts how flexible or restricted/stable the shoulder joint is
what is the intermembral index?
- ratio of limb proportions
forelimb length/hindlimb length = humerus length + radius length/ femur length + tibia length x 100
what is an IMI above 100?
- hindlimb dominated
- leapers/bipeds
what is an IMI at 100?
- forelimb and hindlimb equally dominant
- quadrapeds
what is an IMI below 100?
- forelimb dominated
- suspensory
what are the four categories primates are placed into based on their diets?
- folivore
- frugivore
- insectivore
- gumnivore
folivore
high cusps/crests for shredding and shearing leaves
frugivore
low rounded cusps for crushing fruit pulp
insectivore
high. sharp cusps for piercing and tearing
gumnivore
robust, sometimes lengthened incisors used to chew through tree bark, short molar cusps
what does australopiths stand for?
- australo = southern
- pithecus = ape
what are the two groups the australopiths are divided into?
- robost
- gracile
australopithecus afarensis
- 3.2 mya
- afar region of Ethiopia
- 40% complete with crania and post-crania
which came first, bipedalism or encephalization?
- bipedalism
- Lucy taught us this
what is the purpose of the valgus knee?
- this attribute contributes to bipedalism
- allows the foot to be placed directly below the center of gravity, providing for more efficient bipedal locomotion
adaptations
- characteristics that allow an organism to interact with its environment in a distinctive way
homoplasies
- traits can change rapidly
- the environment or lifestyle might select for the same kinds of traits in different organisms
- are not useful for reconstructing how animals are related
what are the common sexual dimorphic features in primates?
- overall body size/mass
- degree of robusticity
- canine size
- supraorbital torus (brow ridge)
- sagittal crest
what is the foramen magnum?
the large hole at the base of the skull which the spinal cord passes, connecting to the brain
how old is Lucy and where was she found?
- 40% of her skeleton was found in the afar region of ethipia
- dated to 3.2 mya
robust v gracile australopiths
- sagittal crest
- nuchal crest
- post-orbital constriction
- zygomatic arch
between chimpanzees and humans, which one has a skull with a foramen magnum more anteriorly placed? why would the placement need to be different?
- humans = more anterior
- chimpanzees = more posterior
- humans need to have a more forward foramen magnum in order to be bipedal
what group of vertebrae are curved differently in humans compared to other quadrupedal animals?
- curve in the lumbar regions of humans in order to push the spine upright
what role does the os coxa play in the appendicular skeleton?
- plays an important role in how force is transmitted from the axial skeleton to the hindlimbs
describe the placement of the scapula in a macaque and a human
- human = more dorsal
- macaques = more lateral
dental formula of an aye-aye
mandible = 1 - 0 - 0 - 3
maxilla = 1 - 0 - 1 - 3
abducted hallux
the big toe is separated from the other toes
adducted hallux
the big toe is in line with the other toes
what type of hallux do humans have?
adducted
Laetoli footprints
- 1976 in Tanzania
- estimated to be 3.6 mya
- established the origin of bipedalism in hominins
what are the two indicators of bipedal locomotion present in the Laetoli footprints?
- placement of the feet in front of the other
- nonoppossable toes (adducted hallux)
what genus are robust australopiths placed into?
- paranthropus
biological species concept
a species is a group of organisms that are potentially or actually able to interbreed
when did h. heidelbergensis first appear?
- 600,000 - 400,000 kya
when and where were neanderthals present?
- 40,000 kya in europe and the middle east
- complex stone tools and cultural behavior
when did h. floresiensis appear?
- island of flores
- 95,000 - 17,000
- possible descendent of h. erectus
biological profiles
estimations of their age, sex, ancestry, stature, and identifying characteristics based on traits visible and/or measurable in the recovered skeletal remains
clines
geographical gradients
concordant
traits frequently appear together in the same individual
during what age range do the first adult teeth erupt? which teeth are these?
- about 7 years old (+/-2 years)
- first incisors and first molars
by what age range would all deciduous teeth be fully replaced by adult/permanent dentition? by what age are all adult teeth fully erupted?
- 11 years (+/- 2 years)
- 21 years old
suckey-brooks method
- estimate the age range of adult skeletal remains
- combines descriptions of age-related changes in the pubic symphysis with helpful casts of known-age skeletal materials
where are the Australopithecines and Homo habilis found?
- only in africa
where is homo erectus found?
all over the world
homo erectus
- sagittal keel
- football shaped head
homo ergaster
- supraorbital torus
- globular shaped head
allen’s rule
- body shape is more elongated in warm climates and more rounded/compact in cold climates
- compact/round forms have smaller surface area to volume ratios
bergman’s rule
- body size is large in cold climates and small in warm climates
- large bodies have a smaller surface area to volume ratios
canine fossa
- depression on the anterior surface of the maxilla below the infraorbital foramen and on the lateral side of the canine
- just like the chin, a canine fossa is a characteristic of anatomically modern humans
how do you age a child? an adult?
- child = development
- adults = patterns of degeneration
modern human variation
- nasal bridge
- nasal aperture
- nasal sill
what are the two types of incisors?
- shovel shaped
- blade shaped
asian skull characteristics
- orthognathic
- flaring/forward projecting zygomatics
- incisor shoveling
- nasal aperture moderate
- interorbital breadth intermediate
- orbits circular
- nasal architecture tented
european skull characteristics
- pointed face
- midfacial prognathism (zygomatics recede)
- carabelli’s cusp
- nasal aperture narrow
- nasal sill present
- interorbital breadth minimal
- nasal architecture steepled
african skull characteristics
- alveolar prognathism
- receding zygomatics
- nasal spine small
- nasal aperture wide
- nasal architecture round
- interorbital breadth wide
- orbits rectangular
- molar crenulation
small body size - tall cusp height
insectivore
small body size - short cusp height
gumnivore
large body size - tall cusp height
folivore
large body size - short cusp height
frugivore
polygynous
-high sexual dimorphism
- high competition for mates
what are the features of bipedalism?
- knee: valgus angle
- foot: robust tarsals, adducted hallux, and arch in the foot
what is the difference between paranthropus and australopithicus?
- paranthropus is robust while australopiths are gracile
what are the differences between homo erectus and homo ergaster skulls?
- homo ergaster = globular skull
- homo erectus = football shaped skull and sagittal keel
what are the differences between homo sapien and homo neanderthalensis skulls?
- homo sapien = chin, canine fossa, tall forehead
- homo neanderthalensis = occipital bun and retromolar gap
