Human Variation, Adaptation, and Evolutionary Behavior Lecture Flashcards

Vocabulary terms and definitions covering biological adaptation, environmental acclimation, the impacts of colonialism, human sexual variation, and evolutionary theories of behavior.

Adaptation

A result of natural selection where a change in allele frequencies makes a population more fit in a given environment.

Acclimation

A lifetime developmental response in which an individual's body physiologically changes to suit a local environment, which is non-reversible.

Acclimatization

The process in which an individual's body adjusts to a change in its environment with short term, reversible responses.

Melanogensis

A temporary and reversible increase in the production of melanin in response to UVB exposure.

Hypoxia

A condition resulting from a decrease in oxygen concentration when atmospheric pressure drops at high altitude.

Sickle-Cell Anemia

An adaptation resulting from a mutation in the hemoglobin gene that replaces glutamic acid with valine; being heterozygous confers resistance to malaria.

Fermentation

The process of breaking down and preserving food by introducing bacteria, yeasts, and other microbes, which converts lactose into glucose, galactose, and lactic acid.

FADS (fatty acid desaturase gene)

A gene that metabolizes fats; mutations in this gene are an adaptation for humans exploiting limited food resources at high latitudes.

Moken

Austronesian speaking people of the Andaman Sea archipelago whose children have extraordinary underwater vision.

Haenyeos

Female divers in the Korean province of Jeju who exhibit acclimatizations such as heightened BMR and non-shivering.

Bajau

Divers of Indonesia who have enlarged spleens that contract during diving to release additional oxygenated RBCs into the blood stream.

Thrifty Gene Hypothesis

The hypothesis that hunter-gatherers underwent natural selection for rapid nutrient storage genes that are now maladaptive under western diets.

Genetic anachronism

The concept that what was advantageous in the past has been rendered detrimental by progress or adapted to a different time.

Developmental Origins of Health and Disease (DOHaD) Hypothesis

The hypothesis that there is a link between early life experiences, development, and health outcomes later in life.

Dutch Hunger Winter ($1944$-$1945$)

An event where children born to mothers pregnant during a famine had lower birth weights and higher rates of diabetes and obesity, demonstrating intergenerational biological memory.

Epigenetics

Modifications of DNA and/or associated proteins that regulate gene expression without changing the DNA sequence, such as Cytosine Methylation.

Settler Colonialism

A distinct form of colonialism where the settler comes to stay; defined as a structure involving land theft and enslavement rather than a single event.

The Wake

A concept by Christina Sharpe ($2016$) referring to life after slavery, including keeping watch with the dead and coming to consciousness.

Historical Trauma

The cumulative emotional and psychological wounding across generations, including the lifespan, emanating from massive group trauma.

Wilson Bands

Internal enamel micro growth defects resulting from nutritional deficiencies or interruptions.

Intersex

Individuals born with sex characteristics that are not typically male or female or are a blend of both, estimated to be up to $2\%$ of humans.

Pseudoautosomal regions (PAR)

Homologous regions shared by X and Y chromosomes that align and recombine during meiosis.

SRY (sex-determining region)

A DNA-binding protein on the Y chromosome that regulates the expression of genes to initiate male development.

Mosaicism

When a person has $2$ or more genetically different populations of cells in their body, often due to uneven sorting of sex chromosomes during cell division.

Chimerism

When a person is composed of populations of cells with more than $1$ distinct genotype; includes macrochimerism (fused zygotes) and microchimerism.

Microchimerism

The integration of cells from a fetus or sexual partner into a person's body; present in $50$-$70\%$ of parous women.

Complete Androgen Insensitivity Syndrome (CAIS)

A condition where an XY individual has SRY and produces testosterone, but cells do not respond to androgens due to changes in cell receptor function.

Congenital Adrenal Hyperplasia (CAH)

A condition where $46XX$ or $46XY$ individuals produce excess androgens, often due to changes to the $21$-hydroxyalase enzyme in $46XX$ individuals.

$5$-$\alpha$ reductase ($5$-$\alpha RD$)

An enzyme involved in converting testosterone to dihydrotestosterone; mutations in the SRD5A2 gene can result in $46XY$ individuals being born without an external penis.

Mayer-Rokitansky-Küster-Hauser (MRKH)

A condition in $46XX$ individuals where ovaries are functional but the vagina and uterus may be smaller or absent; associated with mutations in the WNT4 gene.

Muller’s ratchet

The process in asexual organisms where harmful mutations accumulate because the least-mutated genotypes are lost by chance and cannot be recreated through recombination.

Intrasexual selection

A mechanism of sexual selection involving competition within males for access to mates.

Intersexual selection

A mechanism of sexual selection involving female mate choice favoring attractive or high-quality traits as 'honest signals'.

Bateman’s Findings

A study on fruit flies concluding higher variability in male reproductive success and that male fertility increases with the number of partners, while female fertility does not.

Parental Investment Theory

A theory by Robert Trivers ($1972$) stating that the sex investing more in offspring (typically females) becomes more selective in choosing mates.

Sarah Hrdy

An anthropologist and primatologist who showed that female langurs are promiscuous to confuse paternity and build alliances to exert power.

Bimaturism

A condition in orangutan males where they can undergo two puberties, the second resulting in increased body size and cheek flanges.

Kin Selection

The idea that natural selection favors behaviors promoting the survival of genetic relatives based on Hamilton’s rule: rB > C.