Primatology and Primate Evolution Review

Primacy practice flashcards covering anatomical traits, classification, geographic distribution, social behaviors, and conservation status of primates.

Encephalization

An increase in brain size relative to body size, where primates have proportionally larger brains than most other mammals of equivalent size.

Stereoscopic vision

3-D vision produced by overlapping visual fields from forward-facing eyes, allowing for the determination of precise distance to objects.

Dermatoglyphs

Fingerprints and toeprints consisting of ridged, highly innervated skin on primate digit tips that provide acute tactile sensitivity.

Pentadactyly

A trait of having five digits on each limb, often including an opposable thumb or pollex.

Binomial nomenclature

A two-name naming system developed by Linnaeus in which each species is identified by its genus name + species name.

Linnaean Classification order

Kingdom → Phylum → Class → Order → Family → Genus → Species.

Strepsirrhines

A group of primates including lemurs, lorises, and galagos characterized by a rhinarium, toothcomb, tapetum lucidum, and grooming claw.

Haplorhines

A group of primates including tarsiers, monkeys, and apes characterized by a dry hairy nose, hemochorial placenta, and increased post-orbital closure.

Rhinarium

The moist, naked nose skin characteristic of strepsirrhine primates.

Lemurs

A primate radiation endemic to Madagascar that arrived via two separate colonization events from mainland Africa.

Platyrrhines

New World monkeys found in Central America, South America, and southern Mexico, with Brazil being the country of highest megadiversity.

Catarrhines

The group comprising Old World monkeys and apes, occurring geographically in Africa, Asia, and small parts of Europe.

Basal Metabolic Rate (BMR) scaling

The principle where larger animals have lower caloric needs per unit of body mass, allowing them to survive on lower-quality foods like leaves.

Fore-gut fermenters

Primates like colobine monkeys with sacculated stomachs that house bacteria to ferment cellulose and neutralize leaf toxins.

Fission-fusion society

A social organization where a large community defends territory together but forages in smaller parties of flexible, variable composition.

Crypsis

The strategy of being undetected, common in solitary nocturnal primates to reduce predation risk.

Intermembral index

A ratio comparing forelimb length to hindlimb length, used to predict locomotion style like leaping or brachiation.

Bilophodont molars

Molar teeth with two transverse ridges, found in cercopithecoid Old World monkeys and efficient for shearing fibrous plants.

Y-5 molar pattern

A molar structure with five rounded cusps in a Y pattern, characteristic of hominoids (apes and humans).

Trichromatic color vision

A derived trait in catarrhines that allows the detection of red and orange fruits and young reddish leaves against green backgrounds.

Tapetum lucidum

A reflective membrane behind the retina that reflects light back across photoreceptors, doubling light capture in low-light environments.

Dominance hierarchy

A ranking system established by aggressive and submissive interactions; it is an emergent property of social interactions rather than an intrinsic trait.

Reconciliation

Affiliative behaviors between former combatants following a conflict to reduce social tension.

Cooperative breeding

A system in callitrichids where all adults in a group help carry and provision infants, which can weigh up to $25\%$ of the mother's body mass.

Dilution of risk

A benefit of group living where the individual's risk of being targeted by a predator decreases as group size increases.

Lethal intergroup aggression

Also known as raiding, a behavior documented in chimpanzees where one community cooperatively kills members of a neighboring community.

Bonobos (Pan paniscus)

A human relative sharing $99\%$ of our DNA that uses socio-sexual behavior to reduce tension and lacks documented lethal intergroup aggression.

Androcentrism

A bias where researcher focus is primarily on male behavior, potentially undervaluing female strategies and alliances.

Habitat loss and fragmentation

The primary driver of primate population decline globally, often caused by deforestation for agriculture and logging.

K-selection

A reproductive strategy involving slow maturation and slow reproductive rates, which makes primate populations recover slowly from declines.