Cline

Gradual change in a phenotypic characteristic from one population to the next.

Prenatal stage

Stage before birth; includes 3 trimesters and lasts 9+ months.

Postnatal stage

Stage after birth that includes neonatal, infancy, childhood, juvenile, puberty, and adolescence.

Adult stage

Life stage that includes the reproductive period and senescence.

Growth velocity

The rate of growth per year.

Senescence

Biological changes in later adulthood that include a reduction in homeostasis.

Menopause

Loss of ovarian function.

Reproductive senescence

A decline in reproductive function with age; very rare in nonhuman primates.

Deciduous dentition

The first set of teeth associated with infancy and childhood.

Permanent dentition

The adult set of teeth.

Sexual dimorphism

Physical differences between males and females of the same species.

Epiphysis

The end portion of a long bone.

Diaphysis

The shaft of a long bone.

Growth plate

Area involved in the growth of a long bone.

Bergmann's Rule

Body mass increases as temperature decreases; larger, rounder bodies help retain heat in cold environments.

Allen's Rule

Appendages tend to increase in size as temperature increases.

Melanin

A chemical substance in skin that screens out UV radiation.

UV radiation

Helps synthesize vitamin D but can also deplete folic acid.

Vitamin D

Important for proper skeletal development.

Light skin

Allows more UV penetration, which helps with vitamin D synthesis in environments with lower UV.

Dark skin

Provides more protection from UV damage in environments with greater sun exposure.

Osteoblasts

Bone-forming cells that synthesize and deposit bone.

Osteoclasts

Bone-resorbing cells that remove bone tissue.

Osteocytes

Mature bone cells involved in bone maintenance.

Wolff's Law

Bone responds, adapts, and remodels in response to biomechanical pressures and needs.

Frontal

Forehead/front portion of the skull.

Parietal

Top and sides of the skull.

Occipital

Back/base of the skull.

Temporal

Side of the skull near the ears.

Maxilla

Upper jaw and large portion of the face.

Hyoid

Bone located in the neck/throat.

Scapula

Shoulder blade.

Humerus

Upper arm bone.

Radius

Forearm bone on the thumb side.

Ulna

Forearm bone on the pinky side.

Femur

Thigh bone.

Tibia

Larger lower-leg bone/shin bone.

Phalanges

Bones of the fingers and toes.

Primate

Usually quadrupedal mammals with grasping hands, forward-facing eyes, and other specialized anatomical and behavioral traits.

Strepsirrhines

Lemurs, lorises, and galagos.

Wet-nose primates

Another description of strepsirrhines; they have a rhinarium.

Rhinarium

The wet nose area characteristic of strepsirrhines.

Strepsirrhine characteristics

Large eyes, often nocturnal, grooming claw, tooth comb, reliance on smell, poor color vision, tapetum lucidum, and smaller brain relative to body size.

Tooth comb

A specialized dental structure found in strepsirrhines.

Tapetum lucidum

A structure associated with the eyes of strepsirrhines that helps with vision in low light.

Haplorhines

“Tarsiers, New World monkeys, Old World monkeys, apes, and humans.”

Dry-nosed primates

Another description of haplorhines; they lack a rhinarium.

Haplorhine characteristics

Larger bodies and brains, vision is dominant, color vision, no tooth comb, fewer teeth, and mostly diurnal.

Tarsiers

Small, nocturnal insect-eating haplorhines that live in Asia and are vertical clingers and leapers.

Platyrrhini

Means “flat nose” and refers to New World monkeys.

New World monkeys

Platyrrhines that live in Central and South America.

Platyrrhine characteristics

Broad-nosed, generally small, arboreal, quadrupedal, and some have prehensile tails.

Catarrhini

Refers to Old World monkeys, apes, and humans; characterized by downward-facing nostrils that are close together.

Old World monkeys

Monkeys associated with Africa and Asia; they are catarrhines.

Bilophodont molars

Molars with ridges joining the cusps on the inner and outer edges, forming two transverse ridges; characteristic of Old World monkeys.

Hominoids

Apes and humans.

Hominoid characteristics

Larger brains and bodies, broad chests, shorter trunks, no tail, and suspensory shoulders.

Hominids

Orangutans, gorillas, chimpanzees, bonobos, humans, and immediate ancestors.

Brachiation

Movement through trees using the arms; gibbons are especially adapted for it.

Gibbons

Small-bodied apes from Indonesia; arboreal, brachiating, very vocal, and socially monogamous.

Orangutans

Asian apes that are frugivorous, strongly sexually dimorphic, and use quadrumanual locomotion.

Gorillas

Largest primates with extreme sexual dimorphism; live in tropical Africa and generally live in tight social groups.

Chimpanzees

Live in multi-male, multi-female groups; males dominate, defend territory, and sometimes hunt in coalitions.

Bonobos

Live in societies with strong female bonds; females form coalitions that can prevent male domination.

Phylogenetics

The field concerned with determining evolutionary relationships between species.

Phylogenetic tree

A tree-like diagram that shows how closely or distantly species are related.

Solitary society

Females occupy individual territories with dependent offspring, while male territories overlap several female territories.

Monogamy

One male and one female live in a pair bond for an extended period.

Polygyny

One male has several reproductively mature females; gorillas are an example.

Polyandry

One female has multiple males; rare in primates and seen in marmosets and tamarins.

Multimale, multifemale

A social group consisting of adult males, adult females, and offspring.

Reproductive strategy

Behavior or adaptations related to gaining reproductive success.

Male reproductive strategy

Males may compete physically for access to females, leading to selection for larger bodies, larger canines, or loud vocalizations.

Female reproductive strategy

Females acquire resources for raising young; higher-ranked females generally obtain more resources.

Dominance hierarchy

The ranking of individuals relative to one another in a primate society.

Altruism

Helping one individual at the expense of another.

Kin selection

Helping relatives in ways that can increase reproductive success.

Mutualism

A relationship where individuals help each other, such as “I’ll scratch your back if you scratch mine.”

Sociality

Living in social groups, which can provide access to mates, food, and protection.

Benefits of group living

Protection from predators, access to mates, and help finding food.

Alarm calls

Calls used to warn group members about predators or other dangers.

Social learning

Learning behaviors from other members of a social group.

Primate culture

Behavior that varies between groups, spreads through a social group, and endures over time.

Vocalizations

Primate sounds that can have important meanings.

Vocal dialects

Differences in vocal communication between groups.

Gestural communication

Communication using physical gestures, such as a hand clasp.

Ape language studies

Studies of ape communication involving systems such as ASL and symbols.

Koko

An ape discussed in the review in relation to ASL.

Kanzi

An ape discussed in the review in relation to ape language studies.