Chapter 10: Early Hominin Origins and Evolution: The Roots of Humanity Flashcards
Mary and Louis Leakey
Started a dynasty of fossil hunting
Australopithecus Boisei
A male skull, has sagittal crest, 1.5 million years ago
What makes us humans?
Bipedalism Use of language Ability to speak Hunting/use of tools Non-honing canines Domestication of plants and animals
Steps to bipedality
Foramen magnum position S-shape of spine Shortened pelvis Leg length extended Valgus knee with bicondylar angle Longitudinal foot arch, not on hands Opposability of hallux or big toe
Difference between masseter muscles in humans and apes
Human: Connects in temporal region
Apes: Connects to sagittal crest
T.H. Huxley
Evidence as to Man’s Place in Nature, using comparitive anatomy
Taung Child
showed that large brains appeared early
Hunting Hypothesis
Charles Darwin suggest bipedality Hominins evolved in Africa Hunting meat=tool use Tool use and language=large brain Tool use=small canine Free hands=bipedalism *Overthrown by data* but good hypothesis because it could be tested
Patchy Forest Hypothesis
Rodman and McHenry
Forests becoming fragmented in patches
African Savanna was spreading and interspersed with retreating forest patches
Bipedalism favored over quadrupedalism in mixed landscape
Two legs are more efficient
Habitual Provisioning Hypothesis
Owen Lovejoy
Given that females are receptive only after infants are self sufficient
More food support from a monogamous male feeds more infants, which can lower Interbirth Interval
Suite of anatomies and behaviors coevolve
Habitual food provisioning
Pair bonding = reduced canine size
Cooperation
Bipedalism
Predicts reduced sexual dimorphism
Benefits of Bipedality
See greater distances
greater ease of transportation of young/food
freeing of hands
run long distances easier
Costs of Bipedality
Standing = increased predator exposure
lifting/carrying = increased back injury
circulatory burden on cardiovascular system like varicose veins
foot injury
Sahelanthropus tchadensis
Chad Africa
2500 km from Rift Valley = Rich fauna of a forest near a lake
small brain
bipedal? suggested by foramen magmum
non honing chewing, small canines like human
Massive brow ridge
Orrorin tugenensis
Tugen Hills, Kenya, Africa forest region
Bipedal, based on femur
Tree climber, based on long curved hand bones, longer fingers
Perihoning Complex, intermediacy of honing and non-honing
Ardipithecus Kadabba
Tim White
Lived in forested environment, Middle Awash Valley
Bipedal, based on toe bone and hallux, shows how it pushed off like humans
Comfortable in trees
Perihoning Complex
Ardipithecus Ramidus
Tim White and Y. Haile-Selassie Cool, wet forest, Middle Awash Valley Small brains Bipedal on ground, quad in trees Tree climbing, based on hand and foot bones Non honing canines lots of c3 plant eating grasping toe
Australopithecus is represented by
hundreds of fossils but without DNA evidence
Australopithecus Anamensis
Maeve Leakey and Alan Walker Known for jaw bone Woodland Living Bipedal, shin bone/tibia Non-honing canines, apically worn May be early descendent from Ardipithecus genus Parallel rows of teeth, like apes larger canines, like apes
Australopithecus Afrarensis
Don Johanson "Lucy" Woodland, grassland mix Bipedal phalanges of intermediate curvature longer arms evidence in shoulders of suspensory locomotion small nonhoning canines large molars and premolars short and stout biped bicondylar angle to femur tibia and ankle, human like Footprints in Laetoli
Australopithecus Deyiremeda
possible new spp with more grasping apelike foot
Australopithecus Platypos
Maeve Leakey
woodland environment, Lomekwi, West of Lake Turkana
Flat faced
small molar teeth
first makes, curators and users of stone tools
evidence of cutting with sharp tools, butchery
Australopithecus Garhi
suggests stone tools
oldowan complex
flake sharp tools
Robus paranthropines
Aethiopicus: Woodland and grassland Cranial Sagittal crest and massive molar and premolars Flaring zygomatic (cheek) bone Boisei: Grassland Cranial Sagittal Crest and massive molars and premolars Flaring zygomatic (cheek) bone
Australopithecus Africanus
Small, nonhoning canines, large premolar and molar
Forest and grassland
Missing mid Sagittal crest
Bipedal
Australopithecus Robustus
Small, nonhoning canines; very large premolars and molars Wider, flared zygomatic and face adapted to grassland Mid-Sagittal crest Bipedal
Australopithecus Sebida
Malapa Cave Forest and grassland, eating c3 diet Small brain, small teeth human like hand and pelvis Mosaic foot, apelike heel
