ANTHR 150 MIDTERM (UofA)

Central Paradox of Race

"Race does not exist" Most anthropologists today agree that race does not exist as a valid biological category
"Race is extremely important" Nonetheless, it is very clear that race is an important part of our lives.
The key is that we can define race in more than one way

System of Folk Heredity

Race as a system of folk heredity.
Sorts people into categories that are seen as inherent and unchangeable.
Operates on a level that is not formal or taught. People will usually say that they know what race they and other people are from, but never actually taught how to do this.

Biological Race

As a biological category, a race is a group of people defined by
1. Common ancestry
2. Genetic and physical similarity

Racialization

the process by which a group of people comes to be seen as a race

Ethnicity

A group of people defined primarily based on their language, culture or faith
This group may have shared ancestry, but shared ancestry is not its most important defining trait

Ethnicity vs. Race

ethnicity: a group of persons who share the same language and customs and who identify with certain recent origins
Race: a geographically and culturally determined collection of individuals who share in a common gene pool and are similar in many characteristics
You can see the overlap between the two.

Blended Inheritance

Traits of parents blend in offspring

Model of heredity

Traits are controlled by discrete genes
2 possible expressions. Dominant and recessive. Studied the seed colour phenotype
Organisms carry 2 genes for each trait. One inherited from each parent. 2 of the same homogenous, two different heterogenous and then show the dominant allele, but the recessive gene is still present and can show up in later generations.
Alleles shown are phenotypes alleles present are genotypes
Genes remain discrete as they are passed on, no blending occurs.
Genes for most different traits are passed on independantly

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

recessive allele

An allele that is masked when a dominant allele is present

Genotype

An organism's genetic makeup, or allele combinations.

Phenotype

An organism's physical appearance, or visible traits.

Homozygous

An organism that has two identical alleles for a trait

Heterozygous

An organism that has two different alleles for a trait

Chromosomes

threadlike structures made of DNA molecules that contain the genes

Where chromosomes are found

In the nucleus

Chromosone number

46 chromosomes
23 pairs

Autosomes

Any chromosome that is not a sex chromosome

X and Y chromosomes

the human sex chromosomes
XX Female
XY Male

Recessive Trait Example

Albinism

Continuos variation

a range of small differences in most traits which is an outcome of the number of genes affecting a trait and the number of experimental factors that influence their expression

Discrete variation

Inherited characteristic that have a limited number of variations, such as the ability or inability to roll one's tongue

polygenic traits

traits controlled by two or more genes
Example: hair and eye colour

Nutritional and Disease Stress

Childhood environment can affect some traits like stature
In malnourished children energy is diverted from growth to the the body's basic needs, causing decreased growth rate
Other factors that can slow growth are infectious disease, intestinal parasites.
These can all lead to shorted stature, so environment affects phenotype

Natural Selection

Individuals with traits best suited to their habitat compete more successfully.
Thus leaving more offspring, greater reproductive success, who inherit their adaptive traits
Frequency of adaptive traits in the population increases
Over time this can cause species to change and new species to appear
It can also cause regional variation due to selective pressures of local environments
However, isolation, gene flow and chance are also important in regional variation

breeding population

Subgroup within the species that primarily breed with each other.
Breeding populations often differ in genetic makeup - certain alleles more or less common
One factor that contributes to regional human physical variation
Factors separating human breeding populations include: geographic barriers, customs and attitudes. These factors change over time

Gene Flow

The movement of genes between breeding populations
It reflects interbreeding between groups
May bring new traits into a group
Helps to maintain genetic variability in small populations
Is a major reason why human populations who live near each other tend to look similar

Founder Effect

May happen if part of breeding population branches off as a separate population
By chance, those who leave may carry alleles in different proportions than the overall group
This can create new breeding populations where previously rare traits are common

Bottleneck Effect

Much of the population dies off rapidly
Genetic diversity decreases, alleles carried by non-survivors lost, alleles carried by survivors become more common
Most alleles, these frequency changes will be due to chance, not selective value. most traits won't impact survival of the event

Adaptation

The general state of being well-suited to a particular environment
A trait that aids in an organism's survival or reproductive success

Stress

Anything causing potentially harmful changes to an individual's normal body function

phenotypic plasticity

the ability of an organism to change its phenotype in response to changes in the environment.

Cultural Adaptation

A cultural practise that buffers as an environmental stress

Regional Variation in Skin Colour

Populations native to high UV regions tend to have darker skin colour
Correlation improves with length of time population has spent in area
Likely scenario: first anatomically modern human populations had dark skin. Lighter skin developed in low UV areas due to selection for reduced melanin production. Tanning helps to buffer stress for seasonal higher UV

Tanning as Acclimatization

The tanning process: UV exposure triggers increased melanocyte activity. Skin colour darkens within hours/days, protecting against UV. Occurs in people of all skin colours
This is acclimatization. Reverses when stress is no longer present. Allows skin to adapt to fluctuating UV levels

Eumelanin

dark brown

Phenomelanin

Yellow/orange

Bergmann's Rule

Animals from colder climate tend to be larger and heavier.
Seen in neanderthals

Allen's Rule

Aminals from colder climates tend to have shorter appendages.
Seen in neanderthals

Nuclear DNA

genetic material in the nucleus of a cell

mtDNA

Mitochondria of our cells have their own DNA
At fertilization, sperm mitochondria are normally eliminated - only ovum's mitochondria passed on.
So mtDNA is identical to mom's unless a mutation happens.

skeletal morphology

We can compare overall morphology.
We can also compare tiny details on bones.
Small extra pores, details of tooth shape. These are heritable, so closely related groups ten to show similar sets of traits.
These are called non-metric skeletal traits

Y chromsome DNA (YDNA)

Only males have Y chromosome
Most of it is passed on intact from father to son
So YDNA is identical to dad's unless a mutation happens

mtDNA and YDNA Lineages

This creates lineages of mtDNA and YDNA
Mutation creates slightly different DNA pattern that is passed to following generations
The people who inherit this pattern form a mtDNA or YDNA lineage.
DNA differences between two lineages provide estimate of how closely they're related. Closely related groups have more similar mtDNA and YDNA than distinctly related groups

Neanderthals

Likely evolved from archaic Homo sapiens in Europe.
Brain size similar to ours by slightly larger
Culture more human than archaic H. sapiens. More sophisticated tools. Ritual burial, care for the elderly. Some evidence of simple art.
aDNA for several individuals known.
Regional variation is seen between European and west Asian Neanderthals

Regional Variation in Neanderthals

Some neanderthals show mutation in one gene (MC1R) linked to skin colour in modern humans. Various MC1R mutations are associated with pale skin and red hair. This was a different mutation but likely had same effect. Presumably adaptation to same pressure (vitamin D)
Others do not show this mutation. Neanderthals likely varied in skin/hair/eye colour. Not clear whether this variation was regional

Cold Climate Adaptation in Neanderthals

European neanderthals show adaptation for cold climate in Ice Age Europe: Large nasal cavity to warm and moisten inhaled air. Very stocky build, short limbs
West Asian Neanderthals do not show these traits as strongly. Reflects warmer, less extreme climate.

Anatomically modern Homo sapiens

Term used to refer to hominins with skeletal traits similar to that of humans living today
Same species as us based on morphology and aDNA
Identifying traits include:
Large brain
High rounded skull, lightly built face with chin, small brow ridge, and vertical forehead
Eventually, complex "fully human" culture including elaborate art and personal ornaments

Archaic Homo sapiens Regional Varitation

Showed regional variation in facial morphology and non-metric skeletal traits.
Regional differences in skin colour also likely.
Some argue regional variation of one species. More pronounced than modern human variation
Others argue for 2-3 related species.
Regardless of number of species, regional variation would have reflected genetic drift, gene flow and selection

Spread out of Africa

Eventually modern homo sapiens spread out of Africa
Middle East - ca 110,000 BP
East Asia - by ca 65,000 BP
Europe - ca. 42,000 BP this was delayed by competition with Neanderthals
They replaced archaic Homo sapiens and Neanderthals

Use of Autosomal DNA

mtDNA and YDNA can miss minor interbreeding.
A mtDNA or YDNA lineage can end eventually even thought the individual actually did have descendants. A man only has daughters. A woman only has sons
Recent work on autosomal DNA. More difficult to study, but much more detail. Can show evidence of interbreeding lost in mtDNA/YDNA
This work has found a more complex story. Evidence for minor interbreeding with other hominins as modern humans spread through Eurasia.

Roots of Modern Variation

We are all mostly descended for a single population in Africa ca. 200,000 BP. Most of the patterned variation we see is recent. As with regional variation in earlier hominins this reflects genetic drift, gene flow, and natural selection.
A minor amount of our variation is older and reflects minor ancestry from other hominins. Some of this is functional, but more work is needed to fully understand it
The variation is just the latest version of a long legacy of constant change and does not follow traditional race divisions.
In come cases variation is shown by genetics and archaeology to be very recent

Greek and Roman Human Variation

Ancient world was diverse - extensive contact between Africans, Asians and Europeans. Trade, Migration, conquest
Greek and Roman thinkers noted regional variation in human appearances
Cause debate over environment or heredity. Etheopians 'burnt black' by hot sun. However, children of migrants resemble parents regardless of environment

Greek Roman Race

No signs of race system similar to ours.
Skin colour was unimportant to status.
No broad racial categories were used
Important unit was the gens, or people

Christianity and Slavery

White and black in Christianity symbolized good and evil. Based on biblical symbolism of light and darkness
Invention of race beings in 1400s and 1500s.
European power expands - contacts and exploitation and/or conquest of other regions
This starts to be justified by ideas of inferiority.
New World peoples not descendants of Adam and Eve? First appearance of the idea of polygenism
Dark skinned Africans as 'sons of Ham' - Ham was Noah's son who was banished and had his skin darkened for sinning. This was used as a justification for the slave trade.

The Invention of Race

Invention of race beings in 1400s and 1500s.
European power expands - contacts and exploitation and/or conquest of other regions
This starts to be justified by ideas of inferiority.
New World peoples not descendants of Adam and Eve? First appearance of the idea of polygenism
Dark skinned Africans as 'sons of Ham'
Idea of biological race starts to appear in European science in 17th-18th centuries
Reflects ideas on inferiority, also general academic interest in classifying all organisms

Changes in Race

Went from a social to a scientific category that was used to explain inferiority.

Francois Bernier (1684)

Physician, philosopher, traveler
Proposed classifying people into four types: Far Easterners, Europeans, blacks, Lapps
Types based on physical appearce - especially skin colour and facial appearance - and location
First known scholar to define human variation in terms of regional/physical traits, not nations or peoples

Linnaeus

Systema Naturae, 1735
Argued for a Platonic (unarguable and real) classification of human beings based on physical, cultural and mental traits

Linnaeus 4 varieties

Europaeus: Sanguine, gentle, acute and inventive, governed by laws
Americanus: Choleric, obstinate, merry and free, regulated by customs
Asiaticus: Melancholy, severe, haughty, avaricious, governed by opinions
Afer: Phlegmatic, crafty, indolent, negligent, governed by caprice

George de Buffon

Of the Varieties of the Human Species (1749)
Also argued for regional types, but not permanent ones as people could change over time
One of the several theorits before Darwin who tied to understand change in nature (evolution)
Considered physical, cultural and mental traits
Types seen as result of regional 'degenerations' from original human forms (white)
Degeneration: slow long term physical change in response to influence of local environment

Friedrich Blumenbach

De generis humani 1776
Studied physical traits, especially skull shapes
Classified humans into 5 types
'Original" Caucasian type
Others resulted from degeneration (same sense as Buffon): Malayan (South Asia), Mongolian (East Asia), American, Ethiopian/Negroid

Skulls and Race

Special focus in the 19th century on size and shape of head/skull
Tool for racial classification.
Indicator of mental ability
Why Skulls?
'Obvious' tool for racial classification: Work of Blumenbach, link to facial appearance
19th c medical research: Role of brain in intellect and personality realized by early 1800s

Monogenism

Single origin of all races
Races seen as local subtypes of one species that spread throughout the world
Modern regional variation is due to local environmental influence since then
Single species -> all human union produce equally viable offspring

Polygenism

Multiple human origins
Races seen as different species
Modern regional variation reflects their original points of origin
'Hybridization of race results in lower fertility and viable offspring
Proponents included Morton, White and Nott
Nott spread Morton's ideas to the public with popular literature and lectures

Impact of 19th Century Racial Science

Writing of racial scientists used by 19th c politicians and writers to justify: Slavery, displacement of native peoples in US, Canada, colonial expansion into other regions

Research on race encouraged four general assumption about human variation:

An individuals appearance and social behavior are fixed expressions of their racial type
Races can be sorted along a hierarchy - some inherently superior to others
Cultural variation worldwide reflects proportion of racial types present in each society
Racial variation explains history of nations and their conflicts

General Concepts of Race in the 1900s

4-5 biological races defined: European, African, Asian, American, Australian or Malay
Definition based on visible traits.
Reality of races was not questioned by most scholars
Subcategories are proposed
Monogentist theory has largely won out

Franz Boas

(1858-1942) German-American biological and cultural anthropologist
Did early work in race based on head measurements

Boas Head Measurments

Opinions on race changed after his later work for the US Immigration Commission (1912) Comparison of head measurements of 1st and 2nd generation immigrants
Found some head measurements are significantly impacted by childhood environment
The variable measurements included some key ones used at the time to define race
He concluded based on this that stable races do not exist. Humans constantly change in response to their environment
Findings largely ignored at the time

human phenotypic plasticity

Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompasses all types of environmentally induced changes that may or may not be permanent throughout an individual's lifespan

Genetics Debunking RACE

New techniques for studying human variation were introduced in the 1920s. ABO and other blood type systems
Researchers hoped these would provide a more objective and scientific way to classify people than skull measurements. However, by the 1930s the data produced began to show the basic flaws of racial classification