key terms Flashcards
characterization in the order of primates
primates–> Haplorhini –>apes and monkeys
–> strepsirrhini lemurs and tarsiers
primate locomotion
Quadrupedal,
bipedal
knuckle walking
brachiation
anthropoid
Monkeys and apes
compared to lemuriformes:
- generally larger body size
- shorter snouts with greater emphasis on vision
- closed orbits (eye sockets)
- less specialized dentition, no comb
- larger and more complex premolars
- derived, square molars
- nails instead of claws
- fuesed mandible
prosimian
lemurs, lorises, bushbabie, tarsiers
strepsirhini
suborder
leumurs and lorises
haplorhini
suborder
tarsiers, monkeys, apes, and humans
old world monkeys
Habitat ranges from tropical jungle to semiarid desert to seasonally snow-covered areas
- Cercopithecidae
- -cercopithecienes: more omnivorous with cheek pouches, arboreal, mostly found in africa
- -colobines: mainly eat leaves
- most are quadrupedal and arboreal
- ischial cllosities, hardened skin on buttocks
- sexual dimorphism
new world monkeys
-70 species in a bunch of arboreal environments
-outward facing nostrils
-size, diet and
ecological adaptation vary
-some possess prehensile tails
-all diurnal, except owl monkey
-quadrupedal, except spidermonkeys are semibrachiators
-most live in mixed sex groups of all ages
apes
blsa
evolutionary trends during cenozoic era
bla
y-5 molar pattern
molars that have 5 cusps, oriented in a manner forming a Y-shaped groove pattern on the surface
(apes and humans)
bilophodonty
molars that have 4 cusps, oriented in 2 parallel rows. characteristic of old world monkeys
mosaic evolution
A pattern of evolution in which the rates of evolution in one functional system vary from those in other systems
e.g bipedality paved the way for brain, behavior, and tool making stuff
taphonomy
the study of the decay of organisms over time, and/or fossilization of organic material. Also, patterns of sedimentation and damage done to organic material post-deposition
dating methods
they place sites and fossils into a time frame
relative dating
- stratigraphy
- fluorine analysis
chronometric dating
- potassium/argon (k/Ar)
- Carbon- 14
- Thermoluminiscence
other
- tree ring dating
- Biostrataphy
stratigraphy
used in relative dating b/c of the law of superpostion stating that a lower stratum (layer) is older than a higher stratum
valuable in reconstructing the history of earth and life
Drawback: disturbances can shift strata and objects making it difficult or impossible to reaconstruct the history
experimental archaeology
helps to understand how artifacts wer made and used by reconstructing prehistoric techniques of stone toolmaking, butchering, etc.
-i.e. using direct percussion or pressure flaking to make stone tools
bipedalism-origins
origin theories:
ecological influences
-vision model
–better view of surroundings
energy efficiency
- efficient walking
- Thermoregulatory model
- -reduces heat gain and increases heat loss
dietary influences
-reach fruit high up in trees
sexual selection and mating influences
- provisioning model
- -male provisioning of female and offspring is easier with bipedalism
Anatomical trends in the pre-australopithecines and australopithecines
b
gracility
reduced muscle attachement and tooth size
laetoli
laetoli footprints showed clear evidence that bipedalism preceded enlarged brains in hominins (showing habitual bipedalism came first as it started in australopithecus afarensis)
East African vs. South African gracile australopithecines
East african: affarenses
south african: africanus
Sahelanthropus tchadensis
A fossil found a while back from a pre-australopith
- named: July 2002
- Location: chad
- Found by: Brunet et al.
- estimated age: 6-7 mya
- cranial remains only
- Dated using index fossils (biostratigraphy)
hominin-like features:
- facially resembles younger species
- small canines
un-hominin-like features:
- Location of foramen magnum
- Brain size: 320-388cc
- U-shaped dental arcade
Orrorin tugenensis
“Millenium man”
pre-australopith fossil
- found in 2000
- location: Western Kenya
- Age estimate: 6 mya
hominin-like:
- inferiorly thick femoral neck
- small canines
un-hominin-like:
- Debate about femoral neck
- Brachiation adaptations apparently present
Ardipithecus
pre-australopith Genus
- found in NE Ethiopia
- around 5.8 mya but maybe 4.4 mya
mosaic of traits not referred to as Pan -Anteiror position of foramen magnum -Smaller canines, no functioning honing complex -Postcanine megadontia (not a Pan trait)
Not Australopithecus b/c
- not fully bipedal: opposable big toe, curved phalanges on hands, primitive pelvis, long arms
- Thinner enamel on teeth
Australopithecus anamensis
Found at 3 sites at Lake Turkana, Kenya
- 4.2-3.9mya
- mix of primitive and derived features
- definitely bipedal (tibia morphology)
gracile
Super hominin
- intermediate dentition (between ARdipithecus and later hominins)
- bipedality based on tibia
- bipedality is not questioned
reasons for Australopithecus
- small body
- small brain
- Prognathism (degree to which face projects in front of braincase)
- Mosaic features (primitive and derived)
- Much too early for it to be Homo
Australopithecus afarensis,
All over east africa
- 3.9-3 mya
- “Lucy) -40% complete; 3.2 mya
- Brain size: 380-430ccs
- Prognathic face
compared to Pan and Homo:
- Primitive features:
- -small brain (380-450cc)
- -Prognathic
- -Strong nuchral crest
- Derived features
- -Intermediate sized canines
- Other key features
- -Short legs
- likely highly dimorphic
- bipedal and climbing
- decendent of anamensis
Australopithecus africanus
- fossil found in south african rock quarry
- 3.5-2.0 mya
- specimen is cmmonly called “Taung Child”
- Estimated to be a five to six years old
Primitive traits:
-Postrcranially similar to A. afarensis
Derived traits:
- less prognathic
- rounded cranium
- Larger brain (450-550 ccs) than A. afarensis
Derived but not human:
- large molars (smaller than later Australopiths)
- Strong lower jaw
- Nasal pillars (only present in southern african)
Kenyanthropus platyops
in the genus Australopithecus
bipedalism anatomy
- spinous processes reduced
- anterior position of the foramen magnum
- vertebral column s-curved
- Adducted big toe
- Double arch in foot
- Vertebrae larger at base of vertebral column
- Femur angled - puts feet under center of mass
- Wider, “basin-like” pelvis
