Biological anthropology

Biological anthropology

Humans have:1. an evolutionary history: phylogeny

All heritable changes that have brought humans to present formBiological evolution is not progressivee.g., not always simple to complex

2. an individual life history: ontogenyPhenotypic expression of traits & attributesBased on genetic and environment factors

Two Basic Ways of explaining natural phenomena• 1. Supernatural

– Immune from evidence– Immune from hypothesis testing– Explanations can’t be proved or disproved

• Belief systems– Accepted on faith.

• superstitions, myths, religions, philosophies– Important in social structuring

• ethics, morals, laws– Affect the way individuals behave toward one another

• Can hold groups of individuals together OR– can keep groups of individuals apart.– enhance the psychological well-being of individuals.

• provide hope and purpose to life– Beliefs are transmitted by teaching

Ca. 42,000 religions

• 2. Scientific explanations• Science = a process for acquiring information

about the natural world• Gotten through our senses

– Empirical evidence– Observations and experiments are repeatable– Facts are supported by evidence.

• Scientific investigations• 1. Something unusual is observed.• 2. Leads to a question: does this skull represent a biped?• 3. One or more hypotheses are developed.

– hypothesis: a testable tentative explanation for a phenomenon.

– A null hypothesis: (H0)

– An alternative hypothesIs (H1)• Approach: collect data (evidence) and attempt to reject

(refute, falsify) each hypothesis.• Bias is removed by attempting to reject hypotheses. They

can’t be proven.

• Accumulations of verifiable facts lead to the 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.

Effects of isolation on diversityCultural anthropology

Cultural vs. biological evolution

• Culture: non-biological adaptations• Sum total of learned traditions, beliefs, values,

and inventions used by a particular society. • Transmission between generations is non-genetic:

teaching• Cultural evolution is progressive• Predictable, sequential improvements in a

particular direction can be made through time.

Reconstructing the recent past

Olsen-Chubbuck siteDiscovered in 1957

Cross-section of anancient arroyoLong-buried by wind-borne deposits.

Part of the excavated arroyo.

Arroyo was 170 feet longRemains of 193 bisonBison occidentalisnot Bison bisonBones in three layers:Bottom: complete skeletons of 13 individual bison.Middle: bones of partially butchered individualsTop layer: individual bones and partially articulated bones in similar piles.Dated at 8,500 ybpHolocene epoch

Projectile pointsassociated withthe bison bones.

Material culture

The reconstruction of events1. Time of year.2. Wind direction3. The stampede.

75% of the bison were completely burchered.Based on numbers of mature bulls, immature bulls, mature cows, immature cows, and calvesThe butchered bison estimated to have produiced56,640 pounds of fresh meat4,000 pounds of edible internal organs5,400 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.

• 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

Plainview point Clovis point