Anthropology 2B: Weeks 5–8 Lecture Notes

A set of vocabulary flashcards covering key concepts from Anthropology Weeks 5-8, including genetics, human variation, primate taxonomy, and hominin evolution.

Heterozygote advantage

The condition where individuals with genotype AS (heterozygous) have resistance to malaria without suffering from sickle cell disease.

Balanced polymorphism

A situation where two or more alleles remain in stable frequencies in a population because of opposing selective pressures.

Anopheles Mosquitoes

The vector responsible for the transmission of Plasmodium falciparum (malaria), which thrived in human agricultural environments.

Lactase persistence

An evolutionary mutation that keeps the lactase gene active into adulthood, allowing for the digestion of milk; often found in cultures with history of cattle domestication.

Discordant variation

The concept that different human biological traits have different geographic patterns and do not cluster together into discrete 'races.'

94% within, 6% between

The statistic showing that $94\%$ of human genetic variation exists within any single population, while only $6\%$ differs between populations.

Cline

A geographic gradient used to analyze the distribution of a single trait across populations rather than grouping people into categories.

Haplotype

A specific nucleotide sequence used to define a group of people (haplogroup) who share similar genetic markers.

Binomial nomenclature

The scientific naming system consisting of Genus followed by species (e.g., Homo sapiens).

Biological species concept

The definition of a species as a group of organisms that can interbreed and produce viable, fertile offspring.

Reproductive isolation

The prevention of interbreeding between populations through extrinsic (physical) or intrinsic (biological) barriers, which drives speciation.

Cladogenesis

Speciation through the splitting of one lineage into two branches sharing a last common ancestor.

Punctuated equilibrium

The evolutionary model characterized by long periods of stasis interrupted by rapid bursts of change.

Adaptive radiation

A burst of cladogenetic events from a generalized species that fills multiple empty ecological niches.

Homology

Shared traits inherited from a common ancestor that indicate a true evolutionary relationship.

Analogy (Homoplasy)

Similar traits that evolved independently in separate lineages and were not present in the last common ancestor.

Parallelism

The independent evolution of similar traits specifically within closely related species.

Derived traits

Modifications or traits that evolved more recently, which are used to construct phylogenetic trees.

Eutheria

An infraclass of placental mammals characterized by the development of a full placenta.

Prehensile

The biological capability of a primate's hands, and sometimes feet or tails, to be used for grasping.

K-selection

A reproductive strategy involving few offspring, high parental investment, and long development periods.

Heterodont

Possessing multiple types of teeth with different functions, such as incisors, canines, premolars, and molars.

Human Dental Formula

The tooth pattern represented as $2:1:2:3/2:1:2:3$, indicating the number of incisors, canines, premolars, and molars per quadrant.

Strepsirrhini

The suborder of primates including lemurs and lorises, characterized by wet noses (rhinarium), dental combs, and an absence of post-orbital closure.

Catarrhini

A parvorder consisting of Old World monkeys, apes, and humans, characterized by narrow nasal septums and nostrils angled downward.

CP3 complex

A dental system in catarrhines where the large upper canine is sharpened against the sectorial premolar (P3) during mouth closure.

Bilophodont molars

Molar teeth with four cusps arranged in two rows or ridges, characteristic of cercopithecoids (Old World monkeys).

Ischial callosities

Thickened skin pads on the buttocks, present from birth, found in cercopithecoids, gibbons, and siamangs.

Y-5 molar pattern

A cusp pattern where five cusps on the lower molars are arranged in a Y-shape, characteristic of hominoids (apes and humans).

Hylobatidae

The family of lesser apes, including gibbons and siamangs, known for being classic brachiators.

Habitual bipedalism

A mode of locomotion on two legs as the primary method of movement, distinguishing humans from other living hominoids.

Sahelanthropus tchadensis

One of the earliest potential human ancestors found in Central Africa, dating to the late Miocene.

Lucy

A famous specimen of Australopithecus afarensis that demonstrated a post-cranial skeleton adapted for bipedalism with an ape-like face.

Robust hominins

Hominin species characterized by large molars, thick mandibles, and zygomatic arches adapted for a tough, fibrous plant diet.

Oldowan

The stone tool industry associated with the early Homo species, such as Homo habilis.

Paleospecies

Species defined by anatomical similarity in the fossil record since reproductive compatibility cannot be tested.

Taphonomy

The scientific field that studies the processes of fossilization and what happens to remains after death.

Stratigraphy

A relative dating technique based on the principle that deeper rock strata are generally older than those above them.

Potassium-Argon (K-Ar) dating

An absolute dating method used for volcanic rock based on the half-life of $1.3 \text{ billion}$ years.

Radiocarbon (C-14) dating

An absolute dating method used on organic materials based on the decay of C-14, which has a half-life of roughly $5,730$ years.

Molecular clock

A method of estimating the time since the split of two lineages by comparing nucleotide differences in homologous gene sequences.