bi 315 final: scientific racism

how do physiological anthropologists define races

they define it as folk taxonomies - classification schemes generated by human culture and not based on underlying scientific or biological framework

race are _________ but are not __________

races are socio-cultural categories but are not biological populations

who came up with the earliest classification of human varieties

linnaeus did and he classified humans into four varieties based on geographic regions (europe, americans, asia, and africa) and skin color.

how did linnaeus lay the groundwork for scientific or biological racism?

he made changes to his classification, he kept the same four human varieties however added characterization of their temperaments, clothing, and systems of government

• ex: wise, greedy sluggish

what is scientific racism or biological racism?

both refer to the same idea, that their is scientific/physiological evidence supporting the interiority of certain human races

what is the actual pattern of genetic diversity

only 0.01% of human DNA sites are variable (have multiple allels); of those, most variants are shared across our typical racial groups

what is the essentialist concept of race?

the essentialist concept views races as fundamentally distinct, biologically separate groups. This idea was dominant up to the 20th century and underpinned much of scientific racism.

what is the population concept of race?

this concept treats races as loosely defined biological populations or proxies for real genetic groupings. It's still commonly referenced today, though it oversimplifies genetic diversity.

what does genetic evidence say about the validity of racial categories?

genetic data show that most human genetic variation exists within so-called racial groups, not between them. The actual pattern of human diversity doesn’t support the idea of biologically distinct races.

how much of human DNA is variable across individuals?

only about 0.01% of human DNA sites are variable (have multiple alleles), and most of those variants are shared across racial groupings.

how has the rapid migration of humans over the past 100K years, affected genetic variation?

humans have a small amount of population structure, but because we've expanded rapidly over the past several hundred thousand years and frequently migrated between regions, our populations have often merged, split, and exchanged genes.

• This has led to a complex, overlapping pattern of genetic inheritance rather than sharply divided groups.

why does africa contain the greatest genetic diversity among humans?

because humans are ancestrally african. as humans migrated out of africa, they carried only a subset of that genetic diversity (founder effect). so today, african populations contain the widest range of genetic variation.

what does clinal mean in the context of human genetic variation?

that genetic variation shifts gradually over geography rather than occurring in clear-cut racial or continental divisions.

describe the adaptive variation that exists among humans.

adaptive variation in humans reflects responses to local environmental conditions (temperature, light regime, available diet) and thus varies clinally as well.

provide a key example of a clinal adaption that was discussed in class

skin pigment as a clinal adaption to light environment

how does melanin contribute to skin pigmentation and protection?

melanin pigments absorb UV radiation, protecting sensitive components like DNA and giving skin its color. This helps prevent cellular damage from UV exposure.

why do people closer to the equator generally have darker skin?

they experience more solar irradiation and UV exposure.

• darker skin, rich in melanin, helps protect against UV damage in these high-exposure environments.

what is the vitamin D–folate hypothesis?

proposes that skin pigmentation reflects a trade-off: UV exposure is needed for vitamin D synthesis but can degrade folate. Darker skin protects folate in high-UV areas; lighter skin allows more vitamin D production in low-UV regions.

if a population lives in a high-UV environment, then what kind of skin pigmentation would you expect and why?

you’d expect darker skin with more melanin. this helps protect against UV-induced folate breakdown

if a population lives in a low-UV environment, then what kind of skin pigmentation would you expect and why

you’d expect lighter skin. with less UV available, lighter skin allows more UV to penetrate and supports vitamin D production

can science be objectively true, by definition?

no, science cannot be objectively true by definition

• observations: can be objectively true but the rest of scientific methods can’t be objectively true because these are things human do.

what example was discussed in class that proves that science isnt always objectively true

comparison between samuel george morton and friedrich tiedemann. both collected accurate cranial volume data from hundreds of skulls and assigned them to racial groups, but reached opposite conclusions.

• morton emphasized mean differences to argue for racial hierarchies in intelligence, while tiedemann emphasized the broad overlap in distributions to argue for racial equality

• shows how interpretation can be shaped by bias, even with similar data.

describe the eugenics movement

it proposed that via selective breeding of human (including forced sterilization of some people), various undesirable physiological and cognitive traits could be bred out of society

what does it mean when diagnostic algorithms are “race-corrected”?

it means race is used as an input variable that adjusts clinical scores. these corrections were often implemented in good faith but can lead to harmful outcomes.

what are two examples of race-corrected health algorithms discussed in class?

The CKD-EPI equation for kidney disease, which adjusts eGFR scores for Black patients, and a general health risk algorithm used by insurers that underestimated Black patients’ needs based on healthcare costs.

how does the kidney disease example show that race correction can be harmful?

it assumed Black patients were healthier, which led to underdiagnosis and delayed treatment, even though many had worse symptoms than white patients with the same scores.

how does the insurance algorithm example show that race correction can be harmful?

at the same algorithm-generated risk score, black patients had more chronic conditions than white patients. because the algorithm used healthcare costs to estimate need, it underestimated how sick black patients were and reduced their access to care.