Legacies of Human Evolutionary History

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Exploring Biological Anthropology:
The Essentials, 3rd Edition

CRAIG STANFORD

JOHN S. ALLEN

SUSAN C. ANTÓN

As you work through this set of chapter slides, keep in mind the notations that are included from your instructor. Open, read carefully, download if necessary, and use in conjunction with your reading and video lesson study. All these components supplement each other. The wise student will keep this in mind.

Chapter 15
Biomedical and Forensic Anthropology

Ok, was it The Doors and Jim Morrison that had the song “This is the End My Friend”? In any case, this is the end, or the final chapter. You made it thus far so don’t poop out now.

Biomedical Anthropology and the Biocultural Perspective

The subfield of anthropology concerned with

issues of health and illness

Both biological and cultural variables

offer important insights into health and illness

*** The Biocultural Perspective: The modern additional ingredient to the soup of evolution is the matter of culture (which varies).

Culture includes technology (includes medicine), marriage patterns, religion, economy. Within a population, all these things are melded into an integrated system that we call “culture.” This in turn is interlinked with human biology and the local environment.

Question: How is this? AND, is it “evolution”? Adaptation/adjust?

Conceptions of beauty: Consider how in our times some folks will elect to modify their bodies anywhere from a simple ear piercing to plastic surgery to look like “Barbie Doll.” In some Asian communities the epicanthic eye fold has been modified to bring about “Western” eyes. Perhaps a less extreme move is the sun tan parlor, but the skin cancer potential is possible.

In the final analysis, it is important to remember that human morphology and behavior result from the dynamic interaction between cultural, biological & environmental factors. N.B. IF the change in morphology “sticks” do we have “evolution”? If the new traits are passed down (genetically) to the next generation, etc., then we have EVOLUTION.

Birth, Growth, and Aging

Human Childbirth
Birth canal
90% of American births are in hospitals
31.8% (2007) are Cesarean delivery
In 1900 only 5% of U.S. births were in hospitals

Patterns of Human Growth

Auxology: the science of growth and development

Stages of Human Growth

The prenatal or gestational stage
Infancy, juvenile stage, adolescence, and adulthood

Human Childbirth: The ultimate “natural” act! However...it doesn’t always run so smoothly. Read the text at p. 389-90 on this.

The common denominator among any and all birthing scenarios, among the rich or poor is the presence of other humans and helpers. Example: Midwife/friends/hospital staff/ and emotional support

NANCY SCHEPER-HUGHES studies on Brazil’s poorest of the poor! Some who live near the outskirts of “town” or at forest edge might choose to “drop” the baby in the bushes and, if “defective” in any way would leave it to die a natural death. Hard choices are made by people with no resources. In some tribal groups the infant is not even named until it reaches its first birth day; infant mortality is a big concern and this approach lessens the emotional impact of losing a child.

QUESTION: Were you or anyone you know born at home? I was, and so were my five brothers and sisters! A mid-wife was key to this approach to birthing.

Human/chimp female birth canals compared (see fig 15.2 p.389): Human infant brain is almost as large as adult chimp brain.

*** What we cannot choose is our overall anatomy; but we can influence its growth & development!

* PATTERNS OF HUMAN GROWTH p. 390: (Auxology= the study of h/g+d) The nature and rates of growth and development are controlled by the complex interaction of internal and external factors. See BIOLOGICAL PLASTICITY at this page.

Internal factors include: Hormones --- “Testosterone” and “Estrogen”

External factors include: Availability & usage patterns of food; the various “diseases” in modern urban life

* STAGES OF HUMAN GROWTH (p.390): 1st the Prenatal Gestational stage; then Infancy; Juvenile; adolescence; adult [common to all primates]

Read up on “growth plates” and “Bone age,” Fusion of growth plates, etc.

Puberty: Primary sexual traits = genitalia, among other things, all develop and become obvious. Want to return to puberty, anyone?

Secondary characteristics, in the male, for example, would be--deepening voice and appearance of facial hair.

Birth, Growth, and Aging (cont’d)

The Secular Trend in Growth

Menarche and Menopause

Aging

Read up on the “Secular Trend in Growth” (see p. 392)

* MENARCHE & MENOPAUSE: The beginning and the end of eggs! Why does menopause happen? [And what about “Manopause”?]

The “grandmother hypothesis (p. 394)

* AGING: Physiological & Non-Adaptive Models:

a. Accumulated damage to DNA in cells due to over exposure to sun or from smoking.

b. Damage from “free radicals” (molecules w/unpaired electrons)

The “grandmother hypothesis” (p. 394) suggests that the long post reproductive years in women (menopause) lend themselves to helping out with children and being a treasure trove of knowledge, experience, and wisdom beneficial to the group.

Infectious Disease and Biocultural Evolution

Human Behavior and the Spread of Infectious Disease
Agricultural
sedentary
water
Mobility and migration

Infectious diseases are those in which a

biological agent or pathogen parasitizes or infects a host

All populations are characterized by specific genetic diseases, to one degree or another.

* Human Behavior & the Spread of Infectious Disease: (p.396)

HOLOCENE = MESOLITHIC and NEOLITHIC (lithic = stone age)

Compare nomadic or Hunter Gatherer groups with settled agricultural or sedentary modern societies and what do we get? Infectious diseases, a tendency toward obesity, etc.

*Industrial Societies (p.397): New environments and increasing ease of air travel bring new selective pressures...e.g., disease, pollution. IN OUR TIME…Environmental ESTROGENS also cause problems when they appear in the air, water, soil and food. DES (diethylstilbestrol)

Infectious Disease and Biocultural Evolution (cont’d)

Infectious Disease and the Evolutionary Arms Race
The immune system
antigens
antibodies
immunoglobulins
Cultural and behavioral interventions
shunning
vaccination
Evolutionary adaptations
sickle cell

Today…ebola, sars, avian flu, and on and on it goes! How about those who refuse vaccinations for measles, etc.?

Diet and Disease

The Paleolithic Diet
Modern diets differ from hunter-gatherer diets

Agriculture and Nutritional Deficiency
Staple foods
Pellagra
Beriberi

Agriculture and Abundance: Thrifty and Nonthrifty Genotypes
Nutritional excess
Thrifty pleiotropic genotype

*DISEASE IN FORAGING, FARMING, & INDUSTRIAL POPULATIONS: ZOONOSES, infectious diseases that are transmitted to humans from other animals. SARS AIDS

* AGRICULTURE & NUTRITIONAL DEFICIENCY: Dependence on single crops can lead to nutritional deficiency, as with “pelegra” from dependence on maize crops. Cardiovascular disease is less frequent in foraging peoples than among urban dwellers: diet, lifestyle, shorter lifespan.

13 to 11,000 years ago Middle Stone Age period (Mesolithic): Please make sure to read up on how the Paleolithic diet was so different in fundamental ways from ours.

Forensic Anthropology: Life, Death, and the Skeleton

Forensic anthropologists work with clues about growth, health, disease, and adaptation that are visible in each of our skeletons
These scientists are specialists in human osteology who use the theory and method of biological anthropology to answer questions about how recent humans lived and died

Forensic Anthropology is employed when skeletal identification and analysis is required for legal purposes...crime scenes, discovery of ancestry, mass grave situations in times of war. See p. 403ff

Cultural identification: clothing, diet, tools, injury etc.

Biomedical: bone age, dentistry, etc.

Field Recovery and Laboratory Processing

Similar to Archaeology

Context is Critical

Mapping, Photography, and Excavation

See p. 404ff.

Field Recovery and Laboratory Processing (cont’d)

Detailed examination
Catalog of all finds (including skeletal remains)
In forensic work, catalog part of strict chain of custody

Skeletal remains cleaned and laid out in anatomical position
Bones inventoried and studied for clues about life and death of individual

Note the proliferation of “forensic” related tv shows in vogue today! Indeed, on such show is titled “Forensic Files.”

Forensic anthropologists examine skeletal remains of Khurdish victims of genocide during the time of Saddam Hussein in Iraq.

The Biological Profile

The biological particulars of an individual as estimated from their skeletal remains; includes estimates of sex, age at death, height, and disease status

THE ADULT SKELETON: By age 20 or so, all growth plates have closed & all teeth, except maybe the third molars (wisdom teeth) are fully formed. See p. 405

* Age related changes: Skull sutures close at fixed rates; pubic symphysis occurs when the two innominates fuse.

* Male and Female Skeletons: sexual dimorphism is slight though real in humans. See figure 15.25 p.407 for Sex Determination of Skeleton.

The Biological Profile (cont’d)

Age at Death Reported as a Range

tooth eruption patterns
tooth wear
long bone development

Fascinating! Read p. 405 on this.

The Biological Profile (cont’d)

Sex
Pelvis
sciatic notch
Skull
male skulls are more robust
mastoid process and muscle marking of the occipital bone tend to be larger in males
brow ridge is heavier on males