Lecture 8 - Sex and Population Affinity

True or False: Sex and gender are the same thing

False!

Sex

Biological, determined by chromosomes

There are intersex states of chromosomes (such as XXY), but this will NOT be tested in this class. Only male and female sexes will be used in this class

Gender

Personal identity, irrespective of sex

Other cultures have other categories of gender, such as "two-spirit"

Gender is a cultural and social concept

True or False: You can tell a person's gender by looking at their bones

False! You can ONLY tell sex by looking at the bones

What are the most useful bones in determining sex?

Pelvis > skull > the long bones

What are the Two Ways to Estimate Sex?

Morphology (Size and Architecture) and Metric (Measurements)

Sexual Dimorphism

Differences in physical characteristics between male and female sexes of the same species

Male vs Female Size Difference

Females about ~92% the size of males

Females mature earlier than males

What does it mean to say that females mature eariler than males, in a physical sense?

Females achieve adult size earlier than males do

Males achieve adult size later

The longer you grow, the larger the size

Important Differences of the Pelvis in SE

Subpubic angle, pubic bone shape, inlet shape

Subpubic Angle in SE

Females have a wide U shaped

Males narrower V shaped

Main Pelvis Characteristics Used in SE

Ventral arc, subpubic concavity, medial aspect of ischiopubic ramus

Other Sex Indicators in Pelvis

Sciatic notch, preauricular sulcus

What is SE in the skull based on?

Size and robusticity of skull

**Population specific

Robust vs Gracile in Skull SE

Robust = big muscle attachments with rougher surface sites

Gracile = smaller and smoother muscle attachment sites

Two Postcranial Measurements for SE

Femoral head, humeral head

Problems of Sex Determination

Large range of human variation due to:

Sexual dimorphism,

Between populations- regional variation,

Personal idiosyncrasies,

Growth and development

Can you accurately estimate sex for subadult humans (kids)?

No!

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Race

Geographically patterned phenotypic variation within a species

Populations that differ in allele frequencies

Race as a cultural concept

Appearance, cultural or ethnic preferences, behaviors, beliefs

Ethnicity

Ethnic group of people whose memberes are identified through a common trait (heritage, culture, language, dialect, religion, etc)

Not necessarily biological

Ancestry/Population Affinity

Biological/genetic heritage in terms of regional divisions

What are some Population Affinities / Ancestral Groups?

Asian, european, african, polynesian

True or False: Race is a cultural concept, NOT a biological one

True!

Estimation of PA uses what?

Skull, particularly the midface, for:

Visual techniques (shapes)

Metric techniques (measurements)

What is FORDISC?

A computer program used to input bone measurements that helps estimate sex, population affinity, and stature