Intro to biological anthropology

• Misconception that humans couldn't have originated from Africa began to shift in 1925 - modern paleoanthropology began in South Africa
• Professor Raymond Dart - recognised the significance of a small fossil from Taung - not fully ape nor fully man; one of our distant ancestors
• Robert Broom - found fossils of adults from caves in the area - Cradle of Humanity - humanities birthplace = Africa
• From the 60's - Cradles' fossils take a back seat to discoveries in East Africa - didn't know how old the fossils were.
• East Africa Rift System - volcanic ash layers between fossil beds, which can be dated.

  Uranium-Lead dating used in the Cradle to determine cave ages - narrows down entire human early record of the Cradle to a brief time window (1-3Mya)
• Flowstones - formed when drip water in the cave flows along the floor. As they form uranium is 'locked' inside, crystal by crystal - this creates a clock of how old the flowstones are. We can extract small amounts of uranium and even smaller amounts of lead produced by uranium decay - isotopes allow the 'clocks' to be read
• Cradle is small - can expect that the same events should be recorded in all caves at the same time

  • 8 caves, 29 flowstones - all dated to the same 6 narrow windows (i.e. 2Mya - all important cave sites were closed - nothing washed into them - flowstones formed)
• Flowstones can only form when it rains more - meaning early humans lived through big changes in the local climate

  • Sediments with fossils - flowstone-sediment-flowstone; signal of changing climates; rain-drier times-rain; fossils accumulated during drier times
• Difficult to determine the age of completely skeletonised remains from their state of preservation
• Literature - decomposition on the ground surface; skeletonization occurs within 3 years of death

  Broad esitmates can be made from bone deconstruction but can't differentiate time periods well
• When bodies are buried, underground decomposition is insufficiently known - no guidelines about the velocity of soft tissue and bone decay; antiquity of remains can't be determined from morphological changes.
• Bones retaining: soft tissue, grease, or odour/ when personal objects are found in the body's vicinity it becomes easier to determine forensic interest
• Forensic relevance - investigation into the remains is needed (circumstances of death and individual identification)

  Criminal investigation - if homicide is prescribed the case is no longer of forensic interest (however, some civil cases may need further investigation for identification)
• Comparing radiocarbon content in the bones to atmospheric radiocarbon bomb curve values - helps determine forensic relevance (discriminating between remains from pre-50's to post-50's), but may not ascertain forensic interest (criminal injunction over the last 50 years - pre->mid 50's remains rules out forensic significance)
• i.e. shallow grave under a hospital in Portugal - no modern artifacts, distinguishing features, extensive post-mortem change, etc; allowed for more reliable approaches to estimate time elapsed since death - lack of distinguishing features -> radiometric dating based on radiocarbon content. Modern or historical?