Reconstructing the recent past

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Reconstructing the recent past

• Olsen-Chubbuck site
• Discovered in 1957

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Cross-section of arroyo

• Long-buried by wind-borne deposits.

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Part of the excavated arroyo.

• Ancient arroyo 170 feet long
• Remains of 193 bison
• Bison occidentalis
• not Bison bison
• Bones in three layers
• Bottom complete skeletons of 13 individual
  bison.
• Middle bones of partially butchered individuals
• Top layer individual bones and partially
  articulated bones in similar piles.
• Dated at 8,500 ybp
• Holocene epoch

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Projectile points associated with the bison bones.
Material culture
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• The reconstruction of events
• 1. Time of year.
• 2. Wind direction
• 3. The stampede.

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• 75 of the bison were completely burchered.
• Based on numbers of mature bulls, immature
  bulls, mature cows, immature cows, and calves
• The butchered bison estimated to have produiced
• 56,640 pounds of fresh meat
• 4,000 pounds of edible internal organs
• 5,400 pounds of fat.
• 100 people could have completed the butchering in
  half a day.
• Enough meat, internal organs, and fat to feed a
  group of 150 for 23 days.

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• Example of Prehistoric cultural evolution
• e.g. projectile points
• Stone industry
• traditions
• ca. 11,200 years ago
• Dent site - 43 miles NE of Denver
• Mammoth hunters Clovis points
• ca. 7,000 years ago
• E Colorado Scottsbluff points
• SE New Mexico Plainview points
• Bison hunters

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Plainview point Clovis point
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Humans

• Humans have
• 1. an evolutionary history phylogeny
• All heritable changes that have brought humans
  to present form
• Biological evolution is not progressive
• e.g., not always simple to complex
• 2. an individual life history ontogeny
• Phenotypic expression of traits attributes
• Based on genetic and environment factors

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Effects of isolation on diversity
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Two Basic Ways of explaining natural phenomena

• 1. Supernatural explanations for natural
  phenomena
• Cannot be tested (proved or disproved)
• Accepted on faith.
• Superstitions, myths, religions, philosophies
• Used to define ways of operating
• ethics, morals, laws
• Belief systems
• hold groups of individuals together and keep
  groups of individuals apart.
• enhance the psychological well-being of
  individuals.
• Provide hope and purpose
• Affect the way individuals behave toward one
  another
• Individuals have to be indoctrinated.the beliefs
  are passed from one generation to the next by
  teaching and learning

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Ca. 42,000 religions
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• 2. Scientific explanations
• Science a process for the acquisition of
  information about the natural world
• Gotten through our senses (empiricism).
• Observations and experiments are repeatable
• Facts are supported by evidence.
• E.g., skull
• Does it represent a biped?

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• Scientific investigations
• Evidence is used to test hypotheses
• Hypothesis a testable tentative explanation for
  a phenomenon.
• Null hypothesis (Ho)
• Alternative hypotheses (H1)
• Approach collect data (evidence) and attempt to
  reject (refute, falsify) the Ho.
• Bias is removed by attempting to reject
  hypotheses. They cant be proven.

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• Accumulations of verifiable facts lead to
• discovery of fundamental truths theories
• Theory means something different to different
  groups of people.
• Science willing to modify conclusions if new
  evidence falsifies previous evidence.

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Cultural vs. biological evolution

• Culture non-biological adaptations
• Sum total of learned traditions, beliefs, and
  values used by a particular society.
• Transmission between generations is non-genetic
  teaching
• Cultural evolution is progressive
• Predictable, sequential improvements can be made
  through time.