ANTA01H3 Lecture 5
Ecofacts: ―natural materials that give environmental information about a site ―
Fig 8-8 (p.181)
E.g. Land snails (not the coin – that would be an artifact!), antlers, pollen grains
Dating methods: relative dating ex. Stratigraphy cross-dating methodological basis:
provides a sequence only; i.e no estimates in actual number of years
Absolute dating (chronometric dating) ex. K/Ar, radiocarbon (carbon-14),
thermoluminescence (TL) most techniques are radiometric; i.e,. steady decay of
radioactive isotope provides estimate in actual number of years
Relative dating: stratigraphy: study of the sequential layering of deposits
Principle of super positioning: lower layers.. deposited before the upper layers‖
Strata: layers of soil or rock. May be called ―level‖
Geological strata: formed by natural processes
Archaeological strata: formed by natural and cultural process.
IF you have something that human did that’s something from culture
Chronometric dating: (gives an age estimate in calendar years)
Most techniques make use of radiometric decay: ―a measure of the rate at which certain
radioactive isotopes—[slowly breaks down] disintegrate‖
Examples for dating inorganic materials: potassium- argon (K/Ar) method, Argon-argon
For dating later organic materials: radiocarbon dating – carbon -14 (14C) dating
Only works for material <1,000 yrs old- 50,000 yrs old
Dendrochronology: ―archeological dating method based on the study of yearly growth rings
in ancient wood‖ = dating by tree rings
Non-radiometric technique – tree rings, core samples – use these to date the structure
Adaptations for bipedality: pelvis--: short, broad pelvis (laterally oriented iliac blade) ,
butterfly shaped– help you interpret the fossil files.
Good for stabilizing weight transmission from the spine . [weight comes from the lower back]
Homosapiens, australopith , chimp - pictures ppt
Foot: must act as a stable support instead of a grasping limb.
Big toe brought in line (abducted)with other toes
Australopith footprint – picture ppt . Longitudinal arch also formed to absorb shock and add
Knee: femur is angled inward, legs are more directly under body , chimps can’t full
extension of knee joint possible. We humans have special morphology.
Foramen magnum: the large hole through which the spinal cord attaches to brain positioned
differently . It positioned very differently for human. Its anterior placed in humans (more
Less robust neck muscles are required to hold the neck upright
Humans doesn’t have that many neck muscles like apes.
3 clusters of early hominins: 1) pre-australopiths (7-4.4 mya)
e.g.: Ardipithecus ramidus (―Ardi‖)
2) australopiths: earlier, more primitive australopiths (4.2-3.0 mya) e.g.: Australopithecus
Later more derived australopiths (2.5-1.2 mya) e.g. paranthropus 3) early homo (2.3-1.4 mya) e.g. homo habilis.
1) Pre-australopiths – sahelanthropus (6-7 mya) – small braincase, similar to modern chimp