the action of moving a skeletal element away from the midline of the body.


the socket of the hip joint; an articular surface that encompasses the head of the femur.


the process of adjusting to a particular environment or niche; a morphological or behavioral feature of an organism that evolved through natural selection to play a role or fulfill a particular function.

adaptive radiation

the rapid divergence and spread of a group of organisms into available ecological niches, followed by a slower period of adaptations to their new environment, commonly resulting in a speciation event; similar to punctuated equilibrium, but on a larger scale.


the action of moving a skeletal element toward the midline of the body.


considered to be between the ages of 12-24 years; the period of growth between puberty and complete fusion of the epiphysis of the long bones.


a unit of hereditary information; an alternate form of a gene that sits at the same position on a chromosome.


the study of the relationship between the growth of an organism's specific part(s) in relation to its entire body.

allopatric speciation

the evolution of a daughter species from a parent species as a result of some barrier to gene flow between the new population and the ancestral population; requires complete reproductive isolation.


refers to tooth socket in the mandible or maxilla.

amino acid

chains of molecules that make up proteins. In total, there are 20 amino acids.

anagenetic speciation

when change is found solely within a lineage, and as changes accumulate over time, successive population differ more and more from the "original" population. Eventually the two separate populations differ enough to be recognized as separate species. In this case, speciation results from microevolutionary changes.


[adj. analogous] characteristics of organisms that are similar and share the same function(s), but are not the result of common ancestry.

anatomic position

a position generally accepted as the natural stance for an organism. In bipedal hominins, the anatomic position is an upright, erect posture with the arms at the sides and the palms of the hands facing forward; in quadrupedal primates, the anatomical position is an upright, bent posture with all four limbs outstretched and palms flat on the ground.


the study of the structure of the body and the relationship to its parts.

Andernach's ossicles

[syn. wormian bones] extra, small bones occuring within cranial sutures. Individual ossicles (small bone) are named for its associated suture. For example, an ossicle that is formed nearest the lambdoidal suture would be referred to as a lambdoidal ossicle.


the fusion of two separate bony parts; an abnoram condition of a joint.


the time period before death.


a relative term used for bipedal hominins (those that travel on two legs) to describe features that are closer to the belly or front of the body; opposite of posterior. The term ventral is a synonym commonly used when referring to quadrupedal anatomy.


[Greek: "human-like shape"] in taxonomic classification, any member of the suborder Anthropoidea, including monkeys, apes, and humans, but excluding tarsiers and lemurs.


the scientific study of humans, human culture, and the evolution of humans; subfields include archeology, cultural anthropology, linguistic anthropology, and physical anthropology.


a large, stationary surface (such as a rock) that a core is struck against in order to remove a flake.


an opening or hole in a bone.


under the superfamily Hominoidea, this includes gibbons and siamangs in the family Hylobatidae and orangutans, gorillas, bonobos, and chimpanzees in the family Pongidae. Characteristics of apes include a larger body size, no tail, more complex behavior and cognitive abilities, and an increase period of infant development.


[syn. derived trait] a new or specialized trait. The presence of nails instead of claws is an apomorphy of primates that sets them apart from other mammals.


refers to activity in trees; tree living.

arboreal quadrupedalism

a mode of locomotion in which the animal moves along horizontal branches with a regular gait pattern involving all four limbs.


the investigation of culture through the study of remains left by humans.


ancient; old.

arrested evolution

when there is little change in morphology or genetics over a long period of time. In some cases, organisms exhibiting arrested evolution are referred to as "living fossils."

articulated pelvis

the right and left os coxae in proper anatomical contact with the sacrum.

articulated skull

cranium and mandible in proper anatomical contact.


the point where two or more bones are joined together. Some articulations are movable joints like the elbow or knee, while some are unmovable like the sutures between cranial bones.


an object modified and/or used by hominins.

artificial selection

the process of selecting and breeding only those plants and animal with desired inherited features for the purpose of producing organisms with more of those desirable features. An example of artificial selection is the breeding of two parent horses known to run fast in the hopes of producing offspring that will win races.


fhe first cervical vertebrae.


the wearing away of a surface through grinding or friction; the gradual reduction in number or strength resulting from stress.

auditory meatus

opening in the temporal bone that is commonly referred to as the ear canal.


[adj. autosomal] all chromosomes except for the sex chromosomes.


the second cervical vertebrae.