Introduction to Primate Taxonomy and Evolutionary Tendencies

Flashcards defining key vocabulary, evolutionary terms, taxonomic classifications, and anatomical adaptations from the lecture on primate taxonomy and evolution.

Phylum Chordata

The taxonomic phylum whose members share a physical spinal column, including vertebrae and a spinal cord.

Class Mammalia

The taxonomic class characterized by animals that produce milk, give birth to live young, and have hair.

Cladogram

A graphical model showing evolutionary relationships between species based on last common ancestors, without showing exact divergence time.

Ancestral characteristic

A trait shared by members of a group because it was present in their last common ancestor, such as body hair in primates.

Derived characteristic

A trait present in a group that has changed through evolutionary time via natural selection, adaptation, or genetic drift, such as prehensile tails.

Prehensile tail

A tail with full gripping ability that functions like an arm or leg, found in some platyrrhine species as an adaptation to arboreal habitats.

Phylogenetic tree

A model showing evolutionary relationships that includes both genetic distance and divergence time between species.

Prosimians

An older taxonomic term referring to strepsirrhines and tarsiers based on shared morphological similarities and ancestral traits rather than true evolutionary ancestry.

Anthropoids

A taxonomic term referring to higher primates, which includes all monkey and ape species.

Hominoidea

The taxonomic superfamily that includes all ape species: gibbons, siamangs, orangutans, gorillas, chimpanzees, bonobos, and humans.

Lesser apes

A informal grouping referring to gibbons and siamangs due to their smaller, more gracile body sizes.

Great apes

An informal grouping comprising orangutans, gorillas, chimpanzees, bonobos, and humans, characterized by larger, robust body sizes and longer life histories.

Plesiadapiforms

Proto-primates in the fossil record that preceded the appearance of true primates.

Power grip

An intensive gripping capability in humans enabled by having relatively long thumbs and wide thumb pads.

Heterodonts

Organisms that possess four distinct types of teeth in their dentition: incisors, canines, premolars, and molars.

Dental formula

A system for classifying dentition based on the count of incisors, canines, premolars, and molars in one quadrant of the mouth, such as $2,1,2,3$ in humans.

Dental comb

A specialized dental structure formed by forward-jutting incisors, found in ring-tailed lemurs and used primarily for grooming.

Orthognathic face

A flatter facial structure that sticks out less, associated with a reduced reliance on olfaction and an increased reliance on visual adaptations.

Stereoscopic vision

Visual perception resulting from overlapping forward-facing visual fields, allowing the brain to produce depth perception.

Postorbital bar

A bony arch connecting the frontal bone to the zygomatic arch behind the eye orbit, found in all primates.

Postorbital plate

A bony structure positioned behind the eye orbit in haplorrhines that completely closes off the back of the eye socket to support forward-facing eyes.