ANT 2511 Exam 3 Sinelli Flashcards
What is a fossil?
the remains of an organism chemically changed into rock
What is taphonomy?
the study of what happens to an organism after death
Best conditions for fossilization?
soil, sediments, water, sand, mud, ash
Steno’s Law of Superposition in Stratigraphy
things on the bottom are older than
things on the top
Cultural dating
things found together can be related and used to date each other
Relative dating
simple observation that one artifact or fossil is older than another. Ex: stratigraphy, biostratigraphy, cultural dating, flourine dating
Absolute dating
methods provide specific dates and time ranges. Ex: K-Argon dating, fission track dating, luminescence dating, dendrochronology
Dendrochronology
based on reading rings of trees
Radiocarbon C14 dating
-based on the
decay of 14C, which is an unstable isotope of carbon.
-Carbon 14 has a half-life of 5,730
years
-Only used on remains of biological organisms
-date up to 50,000 years old
Argon dating
-half-life of circa 1.3 billion years
-based on decay of potassium-40 (40K) to argon-40 (40Ar)
-dates the layers around the fossil to give approximate dates for when fossil was deposited
Hominin
Members of the Family Hominidae that occurred after the split from African great apes
Protohomin
-Early hominin, do not exhibit all the characteristics of hominins. maintain some climbing/ robust features.
-Sahelanthropus tchadensis, Orrorin tuganensis
How is bipedalism in hominids distinct from that of birds and kangaroos?
-“habitual” bipedalism in humans, main form of locomotion
-bipedal posture, body always at 90 degree to walking surface
Skeletal indicators of bipedalism
-foramen magnum position—centered (anterior) toward the back (posterior)
-S-shaped spine
-basin shaped pelvis, (also know impacts on birthing with bipedal pelvis shape)
-lower limb features: enlarged femoral head, knee angled inward, short toes
-arched feet
-Valgus angle (Knees inward)
Foramen Magnum position
Means “Large Hole”
Ape: Spine attaches to back of skull
Hominin: Attaches under skull, indicating bipedalism
Hypotheses of the origin of bipedalism
-Darwin’s: freeing hands, looking over tall grass, ability to make tools, hunting
-Lovejoy’s provisioning: food sharing improves status, status improves fitness, better fitness is everything
“Ghari” meaning
Afar language in Ethiopia meaning “surprise”
Gracile vs. Robust
Gracile: better suited for more varied diet including softer foods along with some meat
Robust: specialized for processing tougher, more abrasive plant materials
Sahelanthropus tchadensis
-Protohominin
–7-6 mya, gracile
-Chad, Southern Sahara
-Small brain (350cc), hominin teeth
Orrorin tuganensis (Millenium Man )
-Protohominin
-6 mya, gracile
-Tugan Hills, Kenya
-biped legbones (long femoral neck), Human like teeth
Ardipithecus kadabba
-Afar Valley, Ethiopia
-5.8-5.2 mya, Gracile
-Tim White
-Bipedal unique toe, reduced canines (evolving teeth), hand bones indicate tree climbing
Ardipithecus ramidus
-Afar Valley, Ethiopia
-4.4 mya
-Tim White
-Evidence for woodland habitat, robust arms for climbing, bipedal, long narrow pelvis, skull resembles Sahlanthropus
Australopithecus anamensis
-Kenya and Ethiopia
-4.2-3.9 mya, Robust
-Meave Leakey
-U-shaped tooth row, thick molar enamel (fruit and foilage), tibia displays bipedal adaptations
-Holotype for Australopithecus
Kenyanthropus platyops
-Kenya, Lake Turkana, Meave Leakey
-3.5 mya, Gracile
-Flat-faced man of Kenya
Australopithecus afarensis
-Afar Valley, Ethiopia
-3.85-2.95 mya, Gracile
-Donald Johanson
-Lucy, The Laetoli footprints, A.L. 333 The “First Family”
-Valgus knee, non-opposable big toe
Australopithecus boisei
-Olduvai Gorge, Tanzania
-2.3-1.3 mya
-cheek teeth 4x larger than humans
-larger brain because of larger body (510cc)
Australopithecus aethiopicus (Black Skull)
-Western Lake, Turkana (Kenya)
-2.7-2.3 mya
-Alan Walker & Richard Leakey
-Black Skull
-410cc brain, huge cheek teeth for specialized diet
-Earliest robust hominin
Australopithecus garhi
-Hadar, Ethiopia
-Tim White
-450cc brain, large teeth
-long legs, striding gait, long forearms
-Probable link between Australopithecus and Homo
Australopithecus africanus
-Taung Cave
-2.5-2 mya, Gracile
-Raymond Dart, Robert Broom
-Taung child, Mrs. Ples
-Brain size 405cc (est. 450cc in adult), High forehead, foramen magnum anterior, moved bipedally but retained climbing adaptations
-Possibly descendant of Australopithecus Afarensis
Australopithecus robustus
-Swartkrans cave
-2-1 mya, Robust
-Robert Broom
-Huge molars, flat face, Sagittal crest
-South African variant of A. boisei, last example of robust hominin
Australopithecus sediba
-Malapa, South Africa
-1.95-1.78 mya, Gracile
-Dr. Lee Berger 2008
-Descended of africanus, evolutionary dead end