Human Biological Variation & Biocultural Adaptations Flashcards

Vocabulary-based flashcards covering human biological variation, environmental adaptations, the social construction of race, epigenetics, and the evolution of sexual behavior.

Adaptation

A result of natural selection consisting of a change in allele frequencies that makes a population more fit for a specific environment.

Acclimation

A lifetime developmental response involving physiological changes during growth that are non-reversible, such as a larger chest cavity in high-altitude populations.

Acclimatization

Short-term, reversible physiological responses to environmental change, such as tanning or shivering.

Adaptive Plasticity

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

Melanogenesis

A form of acclimatization involving the temporary increase in melanin (tanning) to protect DNA from damage caused by UV radiation.

Skin Pigmentation Balance

An evolutionary adaptation that balances the need for folate protection in dark skin and Vitamin D synthesis in light skin.

High Altitude Acclimatization

Short-term responses including an increased breathing rate and a spike in Red Blood Cell (RBC) and hemoglobin production.

EPAS1

A specific gene in Tibetans that represents a genetic adaptation for oxygen processing at high altitudes.

Sickle-Cell Anemia Hemotypes

A mutation where Homozygous ($HbSS$) leads to disease and Heterozygous ($HbAS$) confers malaria resistance.

Lactase Persistence

An evolutionary response to dairying where individuals continue to produce lactase to digest milk into adulthood.

FADS

Fatty acid desaturase genes that have mutated in high-latitude populations like the Inuit to allow for a high-fat, animal-based diet.

Moken

A population whose children show "underwater vision" via pupil constriction as a form of acclimatization.

PDE10A

A gene in the Bajau people associated with an enlarged spleen that acts as a biological scuba tank by releasing oxygenated Red Blood Cells (RBCs).

Clinal Variation

The reality of human genetic variation where traits change gradually over space rather than having clear genetic boundaries.

Human Genetic Variation Distribution

Scientific reality that 85-90 ext{%} of genetic variation exists within any given group rather than between groups.

Hypodescent (One-Drop Rule)

A legal and social rule defining anyone with "one drop" of Black ancestry as Black, used historically to maintain the slave economy.

Hyperdescent

A concept used to "absorb" Indigenous people into whiteness to facilitate land theft.

DOHaD

Developmental Origins of Health and Disease; the study of how prenatal environments impact health, such as the Dutch Hunger Winter leading to obesity and diabetes in descendants.

Weathering

The theory that African American mothers face higher pre-term birth rates due to the cumulative stress of racism rather than innate biology.

Epigenetics

Chemical modifications, such as Cytosine Methylation, that regulate gene expression without changing the underlying DNA sequence.

Layers of Biological Sex

Biological sex viewed as a polymorphic system composed of Chromosomal, Gonadal, Hormonal, Internal structures, and External genitalia.

Intersex

A term describing the up to 2 ext{%} of the population with variations in sexual development, such as CAIS or 5-$\alpha$ reductase deficiency.

Mosaicism/Chimerism

The presence of genetically different cell populations within one body, such as fetal cells remaining in a mother's body.

Muller’s Ratchet

The process where asexual organisms accumulate harmful mutations; sexual reproduction uses recombination to "reset" this ratchet.

Bateman’s Principle (1948)

A now-critiqued claim that males are "promiscuous/eager" and females are "choosy/passive" based on flawed fruit fly data.

Sexual Dimorphism in Apes

Physical size differences that are high in Gorillas/Orangutans due to male-male competition and low in Gibbons/Chimps.