1. B IOARCHAEOLOGICAL A PPROACHES TO THE P AST Archaeology, 6 th Edition

2. This chapter will enable you to answer these questions: 1. How do bioarchaeologists contribute to a study of the past? 2. How do bioarchaeologists determine age and sex for a skeleton? 3. How do bioarchaeologists use paleopathology and bone chemistry to reconstruct the lives of ancient peoples? 4. How are genetic data used to reconstruct population relationships and the ages of migrations?

3. Outline  Introduction  Skeletal Analysis: The Basics  How Well Did the Stillwater People Live?  Reconstructing Diet from Human Bone  Lives of Affluence? Or Nasty, Brutish, and Short?  Cannibalism in the American Southwest?  Archaeology and DNA: Tracing Human Migrations

4. Introduction  Bioarchaeology, the study of the human biological component of the archaeological record.  Exploring bone, bone chemistry, and DNA preserved in human tissues to:  Learn the origin and distribution of disease  Reconstruct human diets  Analyze evidence for biological stress in archaeological populations

5. Skeletal Analysis: The Basics  Osteology, the study of bone.  Burial population, a set of human burials that come from a limited region and a limited time period.  The more limited the region and the time period, the more accurate will be inferences drawn from analysis of the burials.

6. Skeletal Analysis: The Basics  Charnel house, a structure used by eastern North Americans to lay out the dead where the body would decompose.  The bones would later be gathered and buried or cremated.  Bundle burial, burial of a person’s bones, bundled together, after the flesh has been removed or allowed to decay off the bones.

7. Skeletal Analysis: Determining Sex  Men and women differ in the pelvic region.  Sciatic notch, the angled edge of both halves of the posterior (rear) side of the pelvis;  measurement of this angle is used to determine sex in human skeletons.  Although its width varies among populations, narrow notches indicate a male and wider notches indicate a female.

8. Skeletal Analysis: Determining Sex  Adult male skulls tend to be:  more robust than adult female’s,  with heavier brow ridges over and between the eyes,  larger mastoid processes (two protrusions of bone on the bottom of the skull, one beneath each ear)  more rugged muscle attachments.  Male skulls have squarer chins and eye orbits.

9. Skeletal Analysis: Determining Sex

10. Skeletal Analysis: Determining Age  Epiphyses, the ends of bones that fuse to the main shaft or portion of bone at various ages; most bones are fused by age 25. This fact can be used to age skeletons of younger individuals.

11. Skeletal Analysis: Determining Age  Pubic symphysis, where the two halves of the pelvis meet in the groin area; the appearance of its articulating surface can be used to age skeletons.  Degree of tooth wear and loss can help in estimating age, but tooth wear and loss can be related to diet.

12. How Well Did The Stillwater People Live?  Paleopathology, the study of ancient patterns of disease, disorders, and trauma.  Nonspecific indicators of stress in the Stillwater burial population included those caused by nutritional deficiencies and/or nonspecific infectious disease.

13. Stillwater Population: Disease and Trauma  No evidence of specific diseases, including syphilis, tuberculosis or leprosy.  Signs of iron deficiency anemia among the skeletal remains from Stillwater Marsh.

14. Stillwater Population: Disease and Trauma  Porotic hyperostosis, a symptom of iron deficiency anemia in which the skull takes on a porous appearance.  Cribra orbitalia, a symptom of iron deficiency anemia in the bone of the upper eye sockets takes on a spongy appearance.

15. Stillwater Population: Disease and Trauma  Harris Lines, horizontal lines near the ends of long bones indicating episodes of physiological stress.

16. Stillwater Population: Disease and Trauma  Enamel hypoplasias, horizontal linear defects in tooth enamel indicating episodes of physiological stress. Enamel hypoplasias

17. Stillwater Population: Workload  In at least one joint, every single adult skeleton in the Stillwater collection had osteoarthritis, a disorder in which the cartilage between joints wears away, often because of overuse of the joint, resulting in osteophytes and eburnation. A vertebra with osteoarthritis

18. Stillwater Population: Workload  Osteophyte, a sign of osteoarthritis in which bones develop a distinctive “lipping” of bone at the point of articulation.  Eburnation, a sign of osteoarthritis in which the epiphyses of long bones are worn smooth, causing them to take on a varnish- like appearance.

19. Stillwater Population: Workload  Men suffered from osteoarthritis more in hip, ankle and foot; women more in the lumbar vertebrae (lower back).  Long bone cross sections, cross sections of the body’s long bones (arms and legs) used to analyze bone shape and reconstruct the mechanical stresses placed on that bone – and hence activity patterns.

20. Stillwater Population: Workload  The femur cross sections and patterns in osteoarthritis indicated that the people living at Stillwater Marsh walked a great deal to make a successful living, males more than females.  Females carried more, resulting in strain on lower back.

21. Stillwater Population: Paleodemography  Paleodemography, the study of ancient demographic patterns and trends. Uses reconstructed parameters such as life expectancy at birth, the age profile of a population, and patterns in the ages of death.  Mortality profiles, charts that depict the various ages at death of a burial population; based on the age and sex data of burials.

22. The Stillwater Mortality Profile

23.  Ethnographic data indicates that mortality of newborns and toddlers is very high among hunting and gathering populations: 50-60% do not survive to 5 years of age.  The female mortality profile shows an increase in deaths in the early child-bearing years; common for foraging populations.  Few individuals are assigned to the 46–50 and 50+ age categories. A 47-year-old in Stillwater was an elder.

24. Stillwater Population: Stature  Bioarchaeologists estimate stature with equations that relate the length of certain long bones to an individual’s height. The femur is the best bone for computing stature.  Height is a useful measure of overall health because it is related to diet.

25. Stillwater Population: Stature  Larsen found among St. Catherines Island populations that the average agriculturalist male was 1% and the average female was 3% shorter than earlier foraging populations.

26. Reconstructing Diet from Human Bone  Diet can be reconstructed from human bone in several ways.  Dental caries, or cavities, indicate a starchy diet of agriculturalists.

27. Reconstructing Diet from Human Bone  Because they were strictly hunter gatherers and their diet was low in simple carbohydrates, only 3% of Stillwater skeletons had cavities.  They lost their teeth by middle age, generally as a result of excessive tooth wear.

28. Bone and Stable Isotopes  Ancient diets can also be reconstructed by analyzing the carbon and nitrogen stable isotopes preserved in human bone.  Bone collagen, the organic component of bone.  Human bones reflect the isotopic ratios of plants ingested during life.

29. Bone and Stable Isotopes  We reconstruct the dietary importance of plants by measuring the ratio of carbon isotopes in bone collagen.  A diet rich in C4 plants (maize), can produce bones with a higher ratio of 13C to 12C.  Humans who consume large amounts of meat have a higher ratio of 15N to 14N.

30. Comparison of Carbon and Nitrogen Isotopes Stable carbon and nitrogen isotopes for the Stillwater burial population compared with those of Archaic Ontario hunter-gatherers and of Pecos Pueblo maize horticulturalists.

31. Lives of Affluence? Or Nasty, Brutish, and Short?  Stillwater Marsh people were relatively healthy, free of disease, disorders, broken bones, and infection.  But they worked hard, suffered from periods of malnutrition, and few lived beyond age 50.

32. Cannibalism in the American Southwest?  Human bones evidencing tool cut marks in places that suggest flesh was stripped from them;  smashed and broken long bones and vertebrae in the same way animal bones are broken to extract marrow.

33. Cannibalism in the American Southwest?  Other bones evidence “pot polish”, abraded surfaces produced by stirring boiling bones in a ceramic pot.  May be evidence of cannibalism or burial rituals.

34. Archaeology and DNA  Molecular archaeology, the use of genetic information in ancient human remains to reconstruct the past.  Nuclear DNA, genetic material found in a cell’s nucleus; this material is primarily responsible for an individual’s inherited traits.  Gene, a unit of the chromosome that controls inheritance of particular traits.

35. Archaeology and DNA  Mitochondrial DNA (mtDNA), genetic material found in the mitochondria of cells;  it is inherited only from the mother and appears to mutate at a rate of 2-4% per 1 million years.  aDNA, ancient DNA recovered from organic materials in archaeological sites.

36. Prospecting for Ancient DNA  In 1984, Allan Wilson and his student Vince Sarich were the first to identify genetic materials from old tissue.  The next year, Swedish researcher Svante Pääbo cloned DNA from a 4,400-year-old Egyptian mummy.  This was the first time that anyone had applied PCR techniques to ancient humans.

37. Prospecting for Ancient DNA  Wilson and his team continued to collect mtDNA samples from around the world and compared the human data with that of chimpanzees.  All living human groups share all but about 0.6 percent mtDNA.  The 0.6 percent suggests a way to determine the relatedness among living individuals and groups.

38. An African Eve  She was quickly nicknamed Eve, after the biblical first woman and wife of Adam.  Molecular clock, calculations of the time since divergence of two related populations using the presumed rate of mutation in mtDNA and the genetic differences between the two populations.

39. An African Eve  The investigators suggested that all the genetic composition evident in living human populations could be traced to a single African ancestor.  Because mtDNA is passed down strictly through the maternal line, this ancestor must have been female.

40. What Happened to the Neanderthals?  Present in Europe by at least 500,000 years ago; appear in Near East and parts of Asia. Appear to have quickly disappeared by 30,000 years ago.  Biologically, Neanderthals are different from modern humans; adapted to cold climate.

41. What Happened to the Neanderthals?  Some see continuity between Neanderthals and modern Europeans; others see differences too large to place Neanderthals in ancestry of modern humans.  Sequenced nuclear DNA genome from three Neanderthals suggesting infrequent interbreeding between with modern humans some 40,000-50,000 years ago.

42. Summary Questions 1. How do bioarchaeologists contribute to a study of the past? 2. How do bioarchaeologists determine age and sex for a skeleton? 3. How do bioarchaeologists use paleopathology and bone chemistry to reconstruct the lives of ancient peoples? 4. How are genetic data used to reconstruct population relationships and the ages of migrations?