paleoanthropology Flashcards
definition of hominin
earliest evidence dates to end of micocene and includes dental and cranial pieces
- distinguished from greate apes by:
- -bpedal locomotion
- -large brain size
- -toolmaking behavior
mosaic evolution
pattern of evolutino in which the rates of evolution in one functional system vary from those in other systems
hominoids
humans and all apes
hominids
orangutans, gorillas, bonobos, chimps, and humans
paleoanthropology
study of early humans
artifacts
material clues that include objects or aterials made or modified for use by hominins
tahponomy
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
context
the environmental setting where an archaeological trace is found
primary context
the setting in which the archaeological trace was originally deposited
secondary contect
is one to which it has been moved (sucha s by the action of a stream)
dating methods
placing sites and fossils into a time frame
- relative dating
- chronometric dating
relative dating
whether an object is older or younger than other objects
chronometric (absolute) dating
age in years
statigraphy
used in relative dating
- the law of superposition states 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 reconstruct the history
fluorine analysis
applied to bones to assess the amount of flourine in ground water incorporated during fossilization
-the longer the time, the more flourine incorporated
-drawback: only useful with bones found at the same location
Dendrochronology (tree ring dating)
dating based on the analysis of patterns of tree rings in wood
- can date the time at which a tree ring formed
- each ring usually corresponds to a year
chronometric dating techniques
potassium/argon (k/Ar)
- used for dating material between 1 and 5 million years old (good for hominins)
- involves the decay of potassium into argon
- k/Ar has a half-life of 1.25 billiion years
- Best samples include rocks heated extremeley high
Carbon-14
half life of 5730 years
- used to date organic materials
- can estimate ages from just under 1,000 to 60,000 years
Thermoluminiscence
relies on principle of radiometric decay
- stone contains trace amounts of radioactive elements
- heating the rock releases displaced beta particles that glow
- by heating the sample and measuring its amount of glow, a date can be determined
biostrataphy
faunal correlation
- use faunal remains from different site
- Dates when fossil pigs, elephants, antelopes were present can be used to cross check the other methods
Experimental archaeology
helps to understand how artifacts were made and used by reconstructing prehistoric techniques of stone toolmaking, butchering, etc.
environmental determinism
links sample environmental changes directly to a major evolutionary shift in an organism
theories on origin of bipedalism
- ecological influences
- energy efficiency
- dietary influences
- sexual selection and mating influences
ecological influences and bipedalism
bipedal stance allows better view of surrounding
-also exposes to predators though, and doesnt address why other terrestrial primates arent bipedal
Energetic efficiency and bipedalism
efficient walking model
bipedal walking is more energetically efficient
-not evidence that early hominins were walking long distances
thermoregulatory model (bipedalism reason)
recuces heat gain and increases heat loss
postural feeding (bipedalism reason)
began as a way to reach fruit high up in trees
responce to resources model (bipedalism)
resource availability influenced bipedality, group size, body size
sexual selection and mating strategies (provisioning model)
male provisioning of female and offspring (i.e. bringing food back)
-implies monogamous pair bond, not supported
habitual bipeds
bipedalism is most common form of locomotion
obligate bipeds
hominins cannot efficiently locomote in other ways
