abductor: a muscle that moves a part of the body away from the midline of the body.

ABO blood-type system: a blood-type system that consists of two basic antigens, A and B. Blood-type O is the absence of both antigens.

absolute dating: the determination of age with reference to a specific time scale, such as a fixed calendrical system; also referred to as chronometric dating.

acclimatory adjustments: reversible physiological adjustments to stressful environments.

accretion: growth by virtue of an increase in inter-cellular materials.

acrocentric chromosome: a chromosome in which the centromere is near one end, resulting in arms of very unequal length.

Adapidae: family of Eocene prosimians found in North America, Asia, Europe, and possibly Africa; may be related to lemurs and lorises.

adaptation: changes in gene frequencies resulting from selective pressures being placed upon a population by environmental factors; results in a greater fitness of the population to its ecological niche.

adaptive radiation: the evolution of a single evolutionary stock into a number of different species.

adenine: a purine found in DNA and RNA.

adenosine triphosphate (ATP): the main fuel of cells. ATP is manufactured by the mitochondria.

adjustment: the ability of humans to survive in stressful environments by nongenetic means.

adolescent growth spurt: a rapid increase in stature and other dimensions of the body that occurs during puberty.

adult: the period in an individual's life cycle after the eruption of the last permanent teeth.

affiliative behavior: close-proximity behavior that includes touching, grooming, and hugging.

agglutination: a clumping together of red blood cells in the presence of an antibody.

aging: the uninterrupted process of normal development that leads to a progressive decline in physiological function and ultimately to death.

agonistic behavior: behavior that involves fighting, threats, and fleeing.

albinism: a recessive abnormality that leads to little or no production of the skin pigment melanin.

all-male party: among chimpanzees, a small group of adult or adolescent males.

allantois: a sack within the amniote egg in which waste products produced by the embryo are deposited

allele: an alternate form of a gene.

Allen's rule: a rule which states that among endotherms, populations of the same species living near the equator tend to have more protruding body parts and longer limbs than do populations farther away from the equator.

allogrooming: grooming another animal.

allometric growth: the pattern of growth whereby different parts of the body grow at different rates with respect to each other.

allopatric species: species occupying mutually exclusive geographical areas.

alpha chain: one of the two chains that make up the globin unit of the hemoglobin molecule.

alpha-feto protein (AFP): a compound, produced by the fetus, that enters the mother's blood through the placenta. Excessive amounts of AFP may indicate neural tube defects or other fetal abnormalities.

altruistic act: a behavior characterized by self-sacrifice that benefits others.

alveoli: small air sacs, located in the lungs, that are richly endowed with blood capillaries. Oxygen is absorbed by the blood in the alveoli.

amino acid racemization: chronometric dating method based on change in the three-dimensional structure of amino acids from one form to its mirror image over time.

amino acid: a type of molecule that forms the basic building block of proteins.

amniocentesis: a medical technique in which amniotic fluid is removed for study of the fetus.

amnion: a fluid-filled sack, formed from embryonic tissue, that contains the embryo in the amniote egg.

amniote egg: an egg with a shell and several internal members, which made reproduction on land possible.

amniotic fluid: the fluid surrounding the fetus.

amphibians: the earliest class of land vertebrates to evolve, yet have to keep their skin moist and lay eggs in water; includes modern frogs and salamanders.

analogies: structures that are superficially similar and serve similar functions, but have no common evolutionary relationship.

anterior pillars: bony columns located on both sides of the nasal aperture that help withstand the stresses of chewing.

anthropocentricity: the belief that humans are the most important elements in the universe.

anthropoid: a member of the suborder Anthropoidea; includes the New World monkeys, Old World monkeys, apes, and humans.

Anthropoidea: suborder of the order Primates that includes the New World monkeys, Old World monkeys, apes, and humans.

anthropological linguistics: the scientific study of human communication within its sociocultural context and the origin and evolution of language.

anthropometry: the study of measurements of the human body.

antibody: a protein manufactured by the body to neutralize or destroy an antigen.

antigen: a substance that stimulates the production or mobilization of antibodies. An antigen can be a foreign protein, toxin, bacteria, or other substance.

ape: a common term that includes the lesser apes (the gibbons and siamang) and the great apes (the orangutan, common chimpanzee, bonobo, and gorilla).

apomorphic: in cladistics, this term describes derived or advanced characteristics that arose relatively late in members of a group and therefore differ among them. These are useful in assessing genealogical links among taxa.

applied anthropology: the activity of professional anthropologists in programs that have as primary goals changes in human behavior believed to ameliorate contemporary social, economic, and technological problems.

arbitrary: a characteristic of language that refers to the fact that a word, or other unit of sound, has no real connection to the thing it refers to. The meanings of the arbitrary elements of a language must be learned.

arboreal quadrupedalism: see branch running and walking.

arboreal: living in trees.

archaeology: a subdiscipline of anthropology involving the study of the human past through its material remains.

archaic primates: the label attached to the plesiadapiformes of the Paleocene. Lacking many features of the primate complex, the plesiadapiformes are no longer considered to be in the order Primates and the term has fallen into disuse.

archetype: the divine plan or blueprint for a species or higher taxonomic category.

areolar area: the dark area surrounding the nipple of the breast.

artifact: any physical remains of human activity.

artificial gene: a gene that is made in a laboratory and used in place of a defective or undesirable gene.

artificial insemination: the process of mechanically introducing sperm into the female reproductive tract.

assortative mating: the preference or avoidance of certain people as mates for physical or social reasons.

asymmetry of function: see lateralization.

atom: a building block of matter.

auditory bulla: a flat or inflated structure which forms in the floor of the skull, that houses the middle ear.

autapomorphic feature: a feature that is unique to a particular species.

autogrooming: self-grooming.

autosome: a chromosome.

B.P.: "Before Present." the notation commonly used on radiocarbon dates, e.g. 1,000 B.P. = 1,000 years before 1950 A.D., or approximately 1,000 A.D.

back cross: the process of crossing a hybrid with its homozygous recessive parent.

balanced polymorphism: the maintenance of two or more alleles in a gene pool as the result of heterozygous advantage.

band (among geladas): a social group consisting of a number of harems and all-male units.

basal metabolic rate: the measure of the total energy utilized by the body to maintain those body processes necessary for life; the minimum level of heat produced by the body at rest.

base: a subunit of a nucleotide that makes up the DNA and RNA molecules; either a purine or a pyrimidine.

basicranium: the floor of the brain case.

behavioral adjustment: cultural responses, primarily through technology, that make survival in stressful environments possible.

behavioral isolation: see sexual isolation.

behavioral sink: a psychological state characterized by gross distortions of behavior.

behavioral thermoregulation: the use of behavior, such as avoiding or seeking sources of heat, to regulate body temperature.

Bergmann's rule: a rule which states that within the same species of endotherms, populations with less bulk are found near the equator while those with greater bulk are found farther from the equator.

beta chain: one of the two chains that make up the globin unit of the hemoglobin molecule.

biacromial width: a measurement of the width of the shoulders.

bilaterally symmetrical: the condition in which, when something is cut down the middle, the two halves formed are generally mirror images of each other.

bilophodont: a term found in Old World cusps with a small into two pairs.

binomen: a two-part name given to a species in which the first part is the name of the genus and the second is the specific name, for example, Homo sapiens.

binomial nomenclature: a system of naming species that uses binomens.

biological (biotic) environment: the living elements surrounding the organism.

biological anthropology: see physical anthropology.

biological evolution: change in the frequencies of alleles within a gene pool of a population over time.

biological species: a group of interbreeding populations that is reproductively isolated from other such groups.

bipedalism: see erect bipedalism.

bitrochanteric width: a measurement of hip width.

blade: a long slender prismatic flake manufactured by indirect percussion or pressure from a prepared core. (See macroblade and microblade.) At least twice as long as it is wide.

blending theory: an early and incorrect idea that a child is an intermediate between maternal and paternal genetic characteristics.

bone age: a standard age based upon the appearances of centers of ossification and fusions of growth plates.

bone breccia: cave fill that consists of masses of bone cemented together with calcium carbonate that has dissolved out of limestone.

bone hammer: a bone that is used as a hammer in the removal of flakes from a core in the manufacturing of stone tools.

bone industry All the bone artifacts from a particular site.

brachiation: hand-over-hand locomotion along a branch with the body suspended underneath the branch by the arms.

brain lateralization: see lateralization.

branch running and walking: a form of quadrupedalism in which the animal walks along a branch grasping with both the hands and the feet.

breast bud: an elevation of the breast as a small mound; the earliest sign of puberty in the female.

Broca's area: a small area in the human brain that controls the production of speech.

Bronze Age: the stage of cultural history that includes the earliest civilizations and the development of metallurgy.

brow ridge: the ridge of bone above the eye sockets.

bytroop: a multimale group found among baboons and other primates

calendrical system: a system of measuring time that is based on natural recurring units of time, such as revolutions of the earth around the sun. Time is determined by the number of such units that have preceded or elapsed with reference to a specific point in time.

call system: a repertoire of sounds, each of which is produced in response to a particular situation.

Callitrichidae: family of New World monkeys consisting of the marmosets and tamarins.

carbohydrates: organic compounds composed of carbon, oxygen, and hydrogen; includes the sugars and starches.

carnivore: an animal that eats primarily meat.

carrier: a person who possesses a recessive allele in the heterozygous condition.

cast: a representation of an organism created when a substance fills in a mold.

cataract: opacity of the eye lens, often inherited as a dominant. The type may vary according to the action of a modifying gene.

catarrhine nose: a nose in which the nostrils open downward and are separated by a narrow nasal septum; found in Old World monkeys, apes, and humans.

Catarrhini: infraorder of the order Primates that includes Old World monkeys and the hominoids plus various extinct taxa.

catastrophism: the belief that the fossil forms represented in each layer of the earth were destroyed by a catastrophic event and that the next set of plants and animals represented a new creation event and were organisms that survived the catastrophe.

cebid: a member of the family Cebidae; the New World monkeys excluding the marmosets and tamarins.

Cebidae: family of New World monkeys that includes the squirrel, spider, howler, and capuchin monkeys, among others.

Ceboidea: superfamily that includes all the New World monkeys, consisting of the families Callitrichidae and Cebidae.

cell: the smallest unit that is considered to be alive. All living organisms either are one cell or are composed of several cells.

centriole: a pair of small bodies found near the nucleus from which the spindle is formed.

centromere: a structure in the chromosome holding the two chromatics together. During cell division it is the site of attachment for the spindle fibers.

cephalic index: the breadth of the head relative to its length.

Cercopithecidae: family that includes all the Old World monkeys, such as guenons, mangabeys, macaques, and baboons.

Cercopithecinae: subfamily that contains the Old World monkeys that are omnivorous and possess cheek pouches.

Cercopithecoidea: superfamily that consists of the Old World monkeys.

cerebral cortex: the "gray matter" of the brain; the center of conscious evaluation, planning,. skill, speech, and other higher mental activities.

cheek pouch: a pocket in the cheek that opens into the mouth; some Old World monkeys store food in the cheek pouch.

cheek teeth: the premolars and molars.

chin: a bony projection of the lower border of the outside of the mandible.

chondrodystrophic dwarfism: a form of dwarfism in which the individual's head and trunk are of normal size but the limbs are quite short; inherited as a dominant.

chordate: a member of the phylum Chordata characterized by the presence of a notochord, a dorsal hollow single nerve cord, and gill slits at some point in the life cycle.

chorion: a membrane derived from the amnion that lies just beneath the shell in the amniote egg and acts as a surface for oxygen absorption.

chorionic villas biopsy: a method of analyzing the embryo by sampling the tissue of the placenta surrounding the developing embryo.

chromatic: one of the two strands of a replicated chromosome. Two chromatics are joined together by a centromere.

chromosomal aberration: an abnormal chromosome number or chromosome structure.

chromosome: a body in the nucleus of the cell that contains the hereditary material.

chronological age: the period of time since birth.

chronology: arrangement of past events in time.

chronometric dating: a dating system that refers to a specific point or range of time. Chronometric dates are not necessarily exact dates, and they are often expressed as a range.

clade: a group of species with a common evolutionary ancestry.

cladistics: a theory of classification that differentiates between shared ancestral and shared derived features.

cladogram: a graphic representation of the species, or other taxa, being studied, based upon cladistic analysis.

class: a major division of a phylum, consisting of closely related orders.

classification: the ordering of phenomena into groups or other classificatory schemes on the basis of shared attributes (see also type and typology).

cleaver: a large core tool with a straight, sharp edge at one end.

clinal distribution: a distribution of frequencies that show a systematic gradation over space; also called continuous variation.

cline: continuous change in a trait or trait frequency over space or time.

cloning: the process of asexual reproduction in an otherwise multicellular animal.

codominance: the situation in which, in the heterozygous condition, both alleles are expressed in the phenotype.

codon: a sequence of three bases on the DNA molecule that codes a specific amino acid or other genetic function.

Colobinae: subfamily of Old World monkeys that includes the langurs and colobus monkeys; species that are specialized leaf eaters, possessing a complex stomach and lacking cheek pouches.

communication: the transmission and reception of some stimulus or message. In relation to animal life, communication occurs when one animal transmits information to another animal.

community: among chimpanzees, a large group of chimpanzees that, through fission and fusion, is composed of a series of constantly changing smaller units, including the all-male party, family unit, nursery unit, consortship, and gathering.

competition: the situation in which two populations occupy the same or parts of the same niche.

complementary pair: a set of two nucleotides, each on a different polynucleotide chain, that are attracted to each other by a chemical bond. In DNA, adenine and thymine and cytosine and guanine form complementary pairs.

compound tool: a tool that is composed of several parts, for example, a harpoon.

conduction: the movement of heat from one object to another by direct contact.

cones: cells of the retina of the eye. Each of the three types of cones is sensitive to a specific wavelength of light, thereby producing color vision.

consanguineous mating: mating between biological relatives.

consort pair: a male and an estrus female that form a temporary alliance.

consortship: among chimpanzees, a small group consisting of an adult male with an estrus female and her young.

constitutive heterochromatin: chromosomal material that is not thought to contain any actual genes.

continuous variation: see clinal distribution.

control: in the scientific method, a situation in which a comparison can be made between a specific situation and a second situation that differs, ideally, in only one aspect from the first.

convection: the movement of heat from an object to the surrounding fluid, either gas or liquid. Heat causes the fluid to move away from the object.

convergence: the evolution of nonhomologous similarities in different evolutionary lines; the result of similarities in selective pressures.

coprolites: fossilized feces; these contain food residues that can be used to reconstruct diet and subsistence activities.

core area: a section within the home range of a primate population that may contain a concentration of food, a water hole, and a good resting place or sleeping trees and in which most of the troop's time will be spent.

core tool: a tool that is manufactured by the removal of flakes from a core.

cranial capacity: the volume of the brain case of the skull.

creation-science: the idea that scientific evidence can be and has been gathered for creation as depicted in the Bible. Mainstream scientists and the Supreme Court discount any scientific value of creation-science statements.

crenelation: a fine wrinkling found around the base of a tooth.

critical temperature: the temperature at which the body must begin to resist a lowering of body temperature; occurs in the nude human body at approximately 31 degrees C (87.8 degrees F).

cross-cousin preferential marriage: marriage between a person and his or her cross-cousin (father's sister's child or mother's brother's child).

crossing-over: the phenomenon whereby sections of homologous chromosomes are interchanged during meiosis.

cultural determinism: the idea that except for reflexes all behavior is the result of learning.

cultural environment: the complex of products of human endeavor, including technology and social institutions.

cultural evolution: the theory that societal change can be understood by analogy with the processes underlying the biological evolution of species.

culture-bound: the state or quality of having relevance only to the members of a specific cultural group.

culture: learned, nonrandom, systematic behavior and knowledge that can be transmitted from generation to generation.

cusp: a point on a tooth.

cytogenetics: the study of the heredity mechanisms within the cell.

cytology: the study of the biology of the cell.

cytoplasm: material within the cell between the plasma membrane and the nuclear membrane.

cytosine: one of the pyrimidines found in the DNA and RNA molecules.

deciduous teeth: the first set of teeth that develop in mammals; also known as the baby, or milk, teeth.

deletion: a chromosome aberration in which a chromosome breaks and a segment that is not attached to the spindle is not included in the second-generation cell. The genetic material on the deleted section is lost.

deme: the local breeding population; the smallest reproductive population.

dendrite: a branchlike projection from a cell.

dental age: a standard age based upon the time of eruption of particular teeth.

dental arcade: the tooth row as seen from above.

dental comb: a structure formed by the front teeth of the lower jaw projecting forward almost horizontally; found in prosimians.

dental formula: formal designation of the types and numbers of teeth. The dental formula 2.1.2.3/2.1.2.3 indicates that in one-half of the upper jaw and lower jaw there are two incisors, one canine, two premolars, and three molars.

deoxyribonucleic acid (DNA): a nucleic acid that controls the structure of proteins and hence determines inherited characteristics. Genes are portions of the DNA molecule that fulfill specific functions.

deoxyribose: a five-carbon sugar found in the DNA molecule.

dependent variable: a variable that is affected by the independent variable.

development: the process whereby cells differentiate into different and specialized units.

developmental adjustments: alterations in the pattern of growth and development resulting from environmental influence.

diabetes: failure of the body to produce insulin, which controls sugar metabolism; has a complex genetic basis influenced by environmental factors.

diaphragm: a muscle that lies beneath the lungs. When the diaphragm contracts, the volume of the lungs increases, causing a lowering of pressure within the lungs and movement of air from the outside into the lungs. When the diaphragm relaxes, air is expelled from the lungs.

diaphysis: the shaft of a long bone.

diastema: a space between teeth.

differential fertility rate: the situation in which some matings produce more offspring than others.

diphyodonty: the successive development of two sets of teeth, the deciduous and the permanent teeth.

diploid: a term that refers to the full complement of chromosomes (23 chromosomes). The diploid number in humans is forty-six.

discontinuous variation: the distribution of alleles, allele combinations, or any traits characterized by little or no gradation in frequencies between adjacent regions.

discrete signal: a characteristic of language that refers to the fact that signals, such as words, represent distinct entities or experiences. A discrete signal does not blend with other signals.

displacement (behaviors): the situation in which one animal can cause another to move away from food, a sitting place, etc.

displacement (language) The ability to communicate about events at times and places other than those of their occurrence; enables a person to talk and think about things not directly in front of him or her.

distance curve: a graph that shows the total height (or other measurement) of an individual on a series of dates.

diurnal: active during daylight hours.

dizygotic twins: fraternal twins; twins derived from separate zygotes.

DNA hybridization: a method of comparing DNA from different species by forming hybrid DNA.

domestication: the process by which people try to control the reproductive rates of animals and plants by ordering the environment in such a way as to favor certain species.

dominance (behavior): the situation in which one animal may displace another and take preference in terms of sitting place, food, and estrus females.

dominance (genetic): the situation in which, in a heterozygous individual, only one allele is expressed in the phenotype.

dominance hierarchy: a system of social ranking based upon the relative dominance of the animals within a social group.

dorsal: toward the top or back of an animal.

Down's syndrome: a condition characterized by a peculiarity of eyefolds, malformation of the heart and other organs, stubby hands and feet, short stature, and mental retardation; the result of an extra chromosome 21.

duplication: a chromosomal aberration in which a section of a chromosome is repeated.

dyspnea: difficult or painful breathing.

ecological isolation: a form of reproductive isolation in which two closely related species are separated by what is often a slight difference in the niches they occupy; also called habitat isolation.

ecological niche: the specific microhabitat in which a particular population lives and the way that population exploits that microhabitat.

ecology: the study of the dynamic relationships of organisms to each other and the total environment.

ectotherm: an animal that derives much of its body heat from external heat sources.

ectotympanic: a bony element within the middle ear that supports the tympanic membrane or eardrum.

edema: retention of water in the tissues of the body.

effector: an enzyme produced by one of the structural genes that binds with the repressor and prevents the repressor from binding to the operator.

electron spin resonance (ESR): a chronometric dating technique based upon the behavior of electrons in crystals exposed to naturally occurring radioactivity; used to date limestone, coral, shell, teeth, and other materials. Enables trapped electrons within bone and shell to be measured without the heating that thermoluminescence requires.

electrophoresis A method for separating proteins in an electric field.

Ellis-van Creveld syndrome: a rare recessive abnormality characterized by dwarfism, extra fingers, and malformations of the heart; high incidence among the Amish.

embryology: the branch of biology that studies the formation and development of the embryo.

empirical: received through the senses (sight, touch, smell, hearing, taste), either directly or through extensions.

empiricism: reliance on observable and quantifiable data.

encephalization quotient: a number reflecting the increase in brain size over and beyond that explainable by an increase in body size.

endocranial cast: a cast of the inside of the brain case.

endocrine glands: organs that produce hormones.

endotherm: an animal whose body heat is regulated by internal physiological mechanisms.

environment: everything external to the organism.

epidermal ridges: fine ridges in the skin on the hand and foot that are richly endowed with nerve endings and are responsible for a highly developed sense of touch; responsible for fingerprint pattern.

epidermis: the outermost layer of the skin.

epiphyses: secondary centers of ossification near the ends of long bones.

epoch: a unit of geological time; a division of a period.

era: a major division of geological time defined by major geological events and delineated by the kinds of animals and plant life it contains. Humans evolved in the Cenozoic era.

erect bipedalism: in humans, the locomotor pattern in which the body is maintained in an upright posture on two legs while moving by means of a heel-toe stride.

ergonomics The study of scientific data on the human body and the application of such data to problems of design.

erythroblastosis fetalis: a hemolytic disease affecting unborn or newborn infants that is caused by the destruction of the infant's Rh + blood by the mother's anti-Ah antibodies.

erythrocyte: a red blood cell; found in blood, lacks a nucleus, and contains the red pigment hemoglobin.

estrogen: a hormone produced in the ovary.

estrus: the time period during which the female is sexually receptive.

ethnoturbinals: bony plates, occurring as pairs, that are found within the nasal region of the skull and support the nasal membranes.

eugenics: the study of the methods that can improve the inherited qualities of a species.

eukaryote: a cell with a nucleus that contains nDNA.

euprimates: "true" primates; primates that show features of the modem primate complex.

eutherian mammal: a placental mammal.

evolution: the process by which small but cumulative changes in a species can, over time, lead to its transformation; may be divided into two categories: physical evolution (adaptive changes in biological makeup) and cultural evolution (adaptive changes in thought and behavior).

evolutionary ecology: the study of living organisms within the context of their total environment, with the aim of discovering how they have adapted.

exogamy: marriage outside a particular group with which one is identified.

exons: the sequences in the DNA molecule that code for the amino acid sequences of corresponding proteins.

extensor: a muscle that straightens out the bones around a joint.

extinction: the disappearance of a population.

extrasomatic: behavioral.

facial sinus: a hollow, air-filled space in the bones of the front of the skull.

familial hypercholesterolemia: a rare dominant abnormality controlled by a multiple-allele series of at least four alleles. The disease is caused by a defective protein that can result in extremely high levels of cholesterol in the blood.

family unit: among chimpanzees, a small group consisting of a mother with some or all of her offspring.

family: a major division of an order, consisting of closely related genera.

fetalization hypothesis: see neoteny hypothesis.

fission-fusion society: a constantly changing form of social organization whereby large groups undergo fission into smaller units and small units fuse into larger units in response to the activity of the group and the season of the year.

fission-track dating: a dating method based on the operation of a radioactive clock, the spontaneous fission of an isotope of uranium present in a wide range of rocks and minerals. As with potassium-argon dating, with whose time range it overlaps, the method gives useful dates from rocks adjacent to archaeological material.

fitness: the measure of how well an individual or population is adapted to a specific ecological niche.

flake tool: a tool manufactured from a flake.

folivore: an animal that eats primarily leaves.

folk taxonomy: the classification of phenomena on the basis of cultural tradition.

food chain: a sequence of sources of energy in which each source is dependent on another source.

foramen magnum: a large opening in the occipital bone at the base of the skull through which the spinal cord passes.

forebrain: the anterior of three swellings in the hollow nerve cord of the primitive vertebrate brain; formed by a thickening of the wall of the nerve cord.

forensic anthropology: the application of the techniques of osteology and skeletal identification to legal problems.

fossil: the remains or traces of any ancient organism.

founder principle: the situation in which a founding population does not represent a random sample of the original population; a form of sampling error.

four-chambered heart: a heart that is divided into two sets of pumping chambers, effectively separating oxygenated blood from the lungs from deoxygenated blood from the body.

fovea: a depression within the macula of the retina of the eye that contains a single layer of cones with no overlapping blood vessels; the region of greatest visual acuity.

frugivore: an animal that eats primarily fruits.

gamete: a sex cell produced by meiosis that contains one copy of a chromosome set (twenty-three chromosomes in humans). In a bisexual animal the sex cell is either a sperm or an ovum.

gametic mortality: a form of reproductive isolation in which sperm are immobilized and destroyed before fertilization can take place.

gathering: among chimpanzees, the largest observed group within the community.

gene flow: the process in which alleles from one population are introduced into another population.

gene pool: the sum of all alleles carried by the members of a population.

gene therapy: a genetic-engineering method in which a gene is altered and then inserted into a cell to correct an inherited abnormality.

generalized species: species that can survive in a variety of ecological niches.

generalized trait: a trait used for many functions.

genes: the basic units of inheritance, now known to be governed by the specific sequence of the genetic markers within the DNA of the individual concerned.

genetic counselor: a medical professional who advises prospective parents or a person affected by a genetic disease of the probability of having a child with a genetic problem.

genetic determinism: the idea that all behavior, including very specific behavior, is biologically based, in contrast to cultural determinism.

genetic drift: the situation in a small population in which the allelic frequencies of the Fl generation will differ from those of the parental generation due to sampling error.

genetic engineering: the artificial manipulation of the genetic material to create specific characteristics in individuals.

genetic equilibrium: a hypothetical state in which a population is not evolving because the allele frequencies remain constant over time.

genetic load: the totality of deleterious alleles in a population.

genetics: the study of the mechanisms of heredity and biological variation.

genome imprinting: the phenomenon whereby an allele may have a different effect on the offspring depending on the sex of the contributing parent.

genome: all the genes carried by a single gamete.

genotype: the genetic constitution of an individual.

genus: a group of closely related species.

geographical isolation: a form of reproductive isolation in which members of a population become separated from another population by geographical barriers that prevent the interchange of genes between the separated populations.

geographical race: a major division of humankind into large geographical areas wherein people resemble one another more closely than they resemble people in different geographical areas.

gestation: the period of time from conception to birth

gill pouches: structures that form in the early human embryo and that are thought to be homologous to the gill slits of other chordates.

glacial: a period of expansion of glacial ice.

globin: a constituent of the hemoglobin molecule that consists of a globin and four heme units. The globin consists of two alpha and two beta chains.

Gloger's rule: a rule which states that within the same species of endotherms, more heavily pigmented forms tend to be found near the equator and lighter forms away from the equator.

glucose-6-phosphate dehydrogenase (G6PD) deficiency: the lack of an enzyme of the red blood cell inherited as an X-linked recessive. Afflicted individuals develop severe anemia when in contact with the lava bean or certain antimalarial drugs.

gluteal musculature: three muscles of the pelvis that in monkeys and apes act as extensors of the thigh. In humans the gluteus maximus, the largest muscle of the human body, acts as an extensor, but the gluteus minimus and gluteus medius act as abductors.

gout: abnormal uric acid metabolism inherited as a dominant with variable expression.

grammar: the formal structure of a language, comprising phonology, morphology, and syntax.

great apes: the orangutan from Asia and the common chimpanzee, bonobo (pygmy chimpanzee), and gorilla from Africa.

grooming cluster: a small group of closely related females that engage in a high degree of grooming.

grooming: in primates, the activity of going through the fur with hand or teeth to remove insects, dirt, twigs, dead skin, etc.; also acts as display of affection.

ground running and walking: a form of quadrupedalism in which the animal walks on the ground using the hands and the feet; the palms of the hand are flat on the ground.

growth hormone: a hormone produced by the pituitary gland; essential for normal growth.

growth plate: a narrow growth zone between the epiphysis and diaphysis of a bone.

growth: increase in the size or mass of an organism.

guanine: a purine found in the DNA and RNA molecules.

habitat isolation: see ecological isolation.

habitat: the specific area where a species lives.

half-life: the time taken for half the quantity of a radioactive isotope in a sample to decay (see also radioactive decay).

haplotype: a set of genes that determine different antigens but are closely enough linked to be inherited as a unit; also : the antigenic phenotype determined by a haplotype.

hard palate: the bony roof of the mouth that separates the mouth from the nasal cavity, permitting the animal to breathe and chew at the same time.

Hardy-Weinberg equilibrium: a mathematical model of genetic equilibrium : p2 + 2pq + q2 = 1.

harem: a subunit of a larger social group consisting of a male associated with two or more females.

heel-toe stride: a method of progression characteristic of humans in which the heel strikes the ground first and the person pushes off on the big toe.

hegemony: preponderant influence or authority of one individual or social group over another. heliocentric: a sun-centered model of the universe.

heme: a constituent of the hemoglobin molecule that consists of a globin and four home units. Each heme unit contains an atom of iron.

hemochorial placenta: the type of placenta found in most primates in which materials pass between the maternal and fetal bloodstreams through a single vessel wall.

hemoglobin A2: a normal variant of hemoglobin A that consists of two alpha and two delta chains and is found in small quantity in normal human blood.

hemoglobin A: a normal adult hemoglobin whose globin unit consists of two alpha and two beta chains.

hemoglobin C: an abnormal variant of hemoglobin A that differs from the latter in having a single amino acid substitution on the beta chain at the same position as the substitution producing hemoglobin S.

hemoglobin F: a normal variant of hemoglobin, known as fetal hemoglobin, that consists of two alpha and two gamma chains and is found in the fetus and early infant. It is gradually replaced by hemoglobin A.

hemoglobin S: an abnormal variant of hemoglobin A that differs from the latter in having a single amino acid substitution on the beta chain; known as sickle hemoglobin.

hemoglobin: the red pigment in erythrocytes that carries oxygen to and carbon dioxide from body tissues.

hemolytic disease: disease involving the destruction of blood cells.

hemophilia A recessive: x-linked trait characterized by excessive bleeding due to faulty clotting mechanism.

henge: literally, "hanging rock," this term is often applied to the Neolithic stone monoliths found in Britian.

herd: among geladas, a large social unit consisting of several bands that come together under very good grazing conditions.

heterodont dentition: the regional differentiation of teeth by function.

heterozygosity: the quality of being heterozygous. Having two different alleles of a particular gene.

high-altitude mountains sickness: a condition that includes shortness of breath, physical and mental fatigue, rapid pulse rate, headaches; occurs in persons not acclimatized to high altitudes.

higher taxa: taxa above the species level, such as family, order, class, phylum, and kingdom

hindbrain: the posterior of three swellings in the hollow nerve cord of the primitive vertebrate brain; formed by a thickening of the wall of the nerve cord.

holism: the philosophical view that no complex entity can be considered to be only the sum of its parts; as a principle of anthropology, the assumption that any given aspect of human life is to be studied with an eye to its relation to other aspects of human life.

home base: a location to which males and females return in human societies.

home range: the area occupied by an animal or animal group.

hominid: a member of the family Hominidae, which includes humans.

Hominidae: family of the superfamily Hominoidea that includes humans.

hominoid: a member of the superfamily Hominoidea, which includes apes and humans.

Hominoidea: superfamily of the suborder Anthropoidea that includes the apes and humans.

homodont dentition: situation in which all teeth are basically the same in structure, although they may differ in size, as is found in reptiles.

homologous chromosomes: chromosomes of the same pair containing the same genes but not necessarily the same alleles.

homology: a similarity due to inheritance from a common ancestor.

homoplasy: a similarity that is not homologous. Homoplasy can arise from parallelism, convergence, analogy, and chance.

homozygous dominant: having two dominant alleles of the same gene.

homozygous recessive: having two recessive alleles of the same gene.

homozygous: having two like alleles of a particular gene; homozygous dominant when the allele is dominant and homozygous recessive when the allele is recessive.

hormones: complex molecules produced by the endocrine glands that regulate many bodily functions and processes.

human factors research: see ergonomics.

hybrid inviability: a form of reproductive isolation in which a mating between two species gives rise to a hybrid that is fertile but nevertheless does not leave any offspring.

hybrid sterility: a form of reproductive isolation in which a hybrid of two species is sterile.

hybrid: the result of a cross or mating between two different kinds of parents.

Hylobatidae: family of the superfamily Hominoidea that includes the lesser apes, consisting of the gibbons and siamang.

hypercalcemia: a condition characterized by high levels of calcium in the blood, caused by excessive amounts of vitamin D; results in sluggish nerve reflexes and calcification of soft tissues.

hyperplasia: growth by virtue of an increase in the total number of cells resulting from mitosis.

hypertrophy: growth by virtue of an increase in the size of cells.

hypothesis: a statement that stipulates a relationship between a phenomenon for which the researcher seeks to account and one or more other phenomena.

hypothetico-deductive explanation: a form of explanation based on the formulation of hypotheses and the establishment from them by deduction of consequences which can then be tested against the archaeological data.

hypoxia: low oxygen pressure due to being at high altitude.

ilium: the thin, bladelike section superior to the hip socket on the innominate bone.

immunological comparison: a method of molecular biology that compares molecules by use of antigen antibody reactions.

immunological distance (ID): a measure of the strength of an antigen-antibody reaction that is indicative of the evolutionary distance separating the populations being studied.

incest taboo: the prohibition of sexual intimacy between people defined as close relatives.

incest: sexual intercourse between closely related persons.

inclusive fitness: an individual's own fitness plus his or her effect on the fitness of any relative.

incomplete penetrance: the situation in which an allele that is expected to be expressed is not always expressed.

independent assortment: a Mendelian principle which states that differing traits are inherited independently of each other. It applies only to genes on different chromosomes.

independent variable: the variable that can cause change in other variables.

index fossil: a paleospecies that had a very wide geographical distribution but existed for a relatively short period of time, either becoming extinct or evolving into something else.

Indriidae: family of Madagascar prosimians that includes the indri, sifaka, and avahi.

induced mutation: a mutation caused by human made conditions.

induction: a method of reasoning in which one proceeds by generalization from a series of specific observations so as to derive general conclusions (cf. deduction).

Industrial Age: a cultural stage characterized by the first use of complex machinery, factories, urbanization, and other economic and general social changes from strictly agricultural societies.

industrial melanism: a situation in which the frequency of alleles for dark color increases in relation to alleles for light color in response to changes in the environment due to pollution caused by increasing industrialization.

industrial society: a society consisting of largely urban populations that engage in manufacturing, commerce, and services.

infantile: the period in an individual's life cycle from birth to the eruption of the first permanent teeth.

innominate bones: a pair of bones that, with the sacrum section of the vertebral column, make up the pelvis. The innominates join in the front of the pelvis at the pubic symphysis.

insectivore: an animal that eats primarily insects; also a member of the mammalian order Insectivora.

instinct: a genetically-determined pattern of behavior that is characteristic of a species and is often a response to specific internal or environmental stimuli.

intergenerational competition: a system whereby mating between generations is prevented by forcing the young out of the group when they reach sexual maturity.

interglacial: a period of warming between two glacials.

intermediate expression: the situation in which a heterozygous genotype is associated with a phenotype that is more or less intermediate between the phenotypes controlled by the two homozygous genotypes.

intermembral index: the length of the humerus and radius relative to the length of the femur and tibia.

intron: the DNA sequence in a eukaryotic gene that is not translated into a protein.

inversion: a form of chromosome aberration in which parts of a chromosome break and reunite in a reversed order. No genetic material is lost or gained, but the positions of the involved alleles are altered.

ischial callosity: a thickening of the skin overlying a posterior section of the pelvis (ischial tuberosity); found in the Old World monkeys and some apes.

isotopic analysis: an important source of information on the reconstruction of prehistoric diets, this technique analyzes the ratios of the principal isotopes preserved in human bone; in effect the method reads the chemical signatures left in the body by different foods. Isotopic analysis is also used in characterization studies.

juvenile: the period in an individual's life cycle that lasts from the eruption of the first to the eruption of the last permanent teeth.

karyotype: the standardized classification and arrangement of photographed chromosomes.

kin selection: the process whereby an individual's genes are selected by virtue of that individual's increasing the chances that his or her kin's genes will be propagated into the next generation.

kingdom: a major division of living organisms. All organisms are placed into one of five kingdoms : monera, Protista, Fungi, Planti, and Animalia.

Klinefelter's syndrome: a sex-chromosome count of XXY; phenotypically male, tall stature, sterile.

knuckle walking: semierect quadrupedalism, found in chimpanzees and the gorilla, in which the upper parts of the body are supported by the knuckles rather than the palms.

lactation: the production of milk by a female mammal

language: a highly flexible and complex system of communication that allows for the exchange of detailed information about both interior and exterior conditions. As a creative and open system, new signals may be added and new ideas transmitted.

lateralization: the phenomenon in which the two hemispheres of the brain specialize in regard to different functions.

Lemuridae: Madagascar prosimian family that includes the femurs.

lesser apes: the gibbons and siamang of Asia.

lethals: defects that cause premature death.

leukocyte: a white blood cell; functions to destroy foreign substances.

lexicon: in linguistics, the total number of meaningful units {such as words and affixes) of a language.

lexigram: a symbol that represents a word.

life expectancy: the length of time that a person can, on the average, expect to live.

life span: the theoretical, maximum age.

linguistic anthropology: a subdivision of anthropology that is concerned primarily with unwritten languages (both prehistoric and modern), with variation within languages, and with the social uses of language; traditionally divided into three branches: descriptive linguistics, the systematic study of the way language is constructed and used; historical linguistics, the study of the origin of language in general and of the evolution of the languages people speak today; and sociolinguistics, the study of the relationship between language and social relations.

linguistics: the scientific study of language.

linkage: the association of genes on the same chromosome.

lipids: the class of compounds that includes fats, oils, and waxes.

lithosphere: the hard outer layer of the earth.

local races: subdivisions of geographical races. One type consists of partially isolated groups, usually remnants of once larger units. The second type includes fairly large subdivisions that contain a degree of variation within them.

Lorisidae: prosimian family that includes the lords, potto, angwantibo, and galago.

low energy budget: an adaptive strategy by which a minimum of energy is used to extract sufficient resources from the environment for survival.

lumbar curve: a curve that forms in the lumbar region of the spine in humans.

macroevolution: "large-scale" evolution; the evolution of new species and higher taxa.

macula: the central area of the retina, consisting of cones only.

mammals: members of the class Mammalia, a class of the subphylum Vertebrata, that are characterized by a constant level of activity independent of external temperature and by mammary glands, hair or fur, heterodonty, and other features.

mammary glands: glands found in mammalian females that produce milk.

mandibular symphysis: the area where the two halves of the mandible join together.

mandibular torus: a thickening of bone on the inside of the mandible.

marasmus: a form of protein-caloric malnutrition caused by a diet deficient in both protein and carbohydrates.

marsupials: Members of the infraclass Metatheria of the class Mammalia. The young are born at a relatively less developed stage than those of placental mammals; after birth, the young animal attaches to a mammary gland in the pouch, where it continues to grow and develop.

masseter: a muscle of chewing that arises on the mandible and inserts on the zygomatic arch of the skull.

maximum parsimony principle: the principle that the most accurate phylogenetic tree is one that is based on the fewest changes in the genetic code.

mechanical isolation: a form of reproductive isolation that occurs because of an incompatibility in structure of the male and female sex organs.

megafauna: all animals weighing more than 100 pounds

meiosis: the form of cell division occurring in specialized tissues in the testes and ovary that leads to the production of gametes.

melanin: the brown-black pigment found in the skin, eyes, and hair.

melanocyte: a specialized skin cell that produces the pigment melanin.

menarche: first menstruation.

Mendelian population: see reproductive population.

mental foramen: a small opening in the mandible through which blood vessels and nerves pass.

messenger RNA (mRNA): a form of RNA that copies the DNA code in the nucleus and transports it to the ribosome.

metacentric chromosome: a chromosome in which the centromere appears roughly in the center and the two arms are roughly the same length.

methodological individualism (or individualistic method): approach to the study of societies which assumes that thoughts and decisions do have agency, and that actions and shared institutions can be interpreted as the products of the decisions and actions of individuals.

microenvironment: a specific set of physical, biological, and cultural factors immediately surrounding the organism.

microevolution: "small-scale" evolution within a population over relatively short periods of time.

microhabitat: a very specific habitat in which a population is found.

microraces: arbitrary divisions of large local races.

midbrain: the middle of three swellings in the hollow nerve cord of the primitive vertebrate brain; formed by a thickening of the wall of the nerve cord.

mitochondria: bodies found in the cytoplasm that convert the energy in the chemical bonds of organic molecules into ATP.

mitochondrial DNA (mtDNA): a double-stranded loop of DNA found within the mitochondria. There can be as few as one or as many as several hundred mitochondria per cell, and each mitochondrion possesses between four and ten mtDNA loops.

mitosis: the form of cell division whereby one celled organisms divide and whereby body cells divide in growth and replacement.

model: a system of hypothetical principles that represents the characters of a phenomenon and from which predictions can be made.

modified brachiation: a slower and more cautious form of brachiation; seen in the orangutan.

modifying gene: a gene that alters the expression of another gene.

mold: a cavity left in firm sediment by the decayed body of an organism.

molecular biology: the comparative study of molecules.

molecule: a unit composed of two or more atoms linked by a chemical bond.

monkey: any member of the superfamilies Ceboidea (New World monkeys) and Cercopithecoidea (Old World monkeys).

monocausal explanation: the attribution of one cause to the existence of a phenomenon.

monogamous family: a social group, found among lesser apes and other primates, consisting of a single mated pair and their young offspring.

monophyletic taxon: a taxon containing species that are all descended from the same single common ancestor.

monotremes: members of the subclass Prototheria of the class Mammalia; the egg-laying mammals.

monozygotic twins: identical twins; twins derived from a single zygote.

morphology: the study of structure, including the system by which speech units are combined to form meaningful words.

mosaic evolution: the concept that major evolutionary changes tend to ttake place in stages, not all at once. Human evolution shows a mosaic pattern in the fact that small canine teeth, large brains, and tool use did not all evolve at the same time. Mossbauer spectroscopy: a technique used in the analysis of artifact composition, particularly iron compounds in pottery. It involves the measurement of the gamma radiation absorbed by the iron nuclei, which provides information on the particular iron compounds in the sample. and hence on the conditions of firing when the pottery was being made.

mounting: a behavioral pattern whereby one animal jumps on the posterior area of a second animal as a part of the act of copulation or as a dominance display.

multicausal explanation: the attribution of more than one cause to the existence of a phenomenon.

multimale group: a social unit consisting of many adult males and adult females.

multiple-allele series: a situation in which a gene has more than two alleles.

multiplication-of-species model: the idea that a generalized species can give rise to a large number of new species, sometimes rapidly.

multivariate explanation: explanation of culture change, e.g. the origin of the state, which, in contrast to monocausal approaches, stresses the interaction of several factors operating simultaneously.

mutation: an alteration of the genetic material.

natural selection: the process whereby members of a species who have more surviving offspring than others pass their traits on to the next generation, whereas the less favored do not do so to the same degree.

negative eugenics: a method of eliminating deleterious alleles from the gene pool by encouraging persons with such alleles not to reproduce.

neocortex: a gray covering on the cerebrum of some vertebrates; the site of higher mental processes.

neoteny hypothesis: a theory of evolutionary change which holds that organisms in a group maintain younger characteristics of ancestral groups while becoming sexually mature during what was previously an infantile or juvenile stage of development; also, the retarded development of specific characteristics.

New World semibrachiation: a locomotor pattern involving extensive use of the hands and prehensile tail to suspend and propel the body; seen in species otherwise quadrupedal.

niche: the environmental requirements and tolerances of a species; sometimes seen as a species' "profession" or what it does to survive.

nocturnal: being primarily active at night.

nondisjunction: an error of meiosis in which the members of a pair of chromosomes move to the same pole rather than to opposite poles.

nonverbal communication: the various means by which humans send and receive messages without using words (e.g., gestures, facial expressions, touching).

norm: the most frequent behavior that the members of a group will show in a specific situation.

Notharctinaet: subfamily of the Adapidae, found primarily in North America.

notochord: a cartilaginous rod that runs along the back (dorsal) of all chordates at some point in their life cycle.

nuchal crest: a flange of bone in the occipital region of the skull that serves as the attachment of the nuchal musculature of the back of the neck.

nuchal muscle: the muscle in the back of the neck that functions to hold the head up. In primates with heavy facial skeletons, the large nuchal muscle attaches to a nuchal crest.

nuclear DNA (nDNA): DNA found within the nucleus of the cell.

nuclear membrane: a structure that binds the nucleus within the cell.

nucleic acid: the largest of the molecules found in living organisms; composed of chains of nucleotides.

nucleotide: the basic building block of nucleic acids; composed of a five-carbon sugar (either ribose or deoxyribose), a phosphate, and a nitrogenous base (either a purine or pyrimidine).

nucleus: a structure found in the cell that contains the chromosomes.

nursery unit: among chimpanzees, a group of several family units (mothers with offspring) and sometimes females without infants.

obesity: a condition in which a person's weight is 20 percent greater than a sex- and age-specific weight-for-height standard.

occipital condyles: two rounded projections on either side of the foremen magnum that fit into a pair of sockets on the top of the spine, thus articulating the skull with the spine.

occipital torus: a horizontal bar of bone seen above the angularity in the occipital.

Old World semibrachiation: a locomotor pattern involving extensive use of the hands in leaping; seen in basically quadrupedal animals.

Oldowan industry: the earliest toolkits, comprising flake and pebble tools, used by hominids in the Olduvai Gorge, East Africa.

olfactory: referring to the sense of smell.

Oligopithecidae: family represented by a single specimen from the Early Oligocene of the Fayum, Egypt.

omnivorous: eating both meat and vegetable food.

Omomyidae: family of Eocene and Oligocene primates, showing some resemblance to the tarsiers, found in North America, Europe, Asia, and Africa.

one-male group: a social unit consisting of a single male associated with several females.

ontogeny: the processes of growth and development of the individual from conception to death.

ontology: the study of ontogeny.

oogenesis: the production of ova.

open: a characteristic of language that refers to the expansionary nature of language, which enables people to coin new labels for new concepts and objects.

operator: a site in the operon to which a repressor can bind, shutting off transcription of structural genes in the operon.

operon: a group of genes all controlled by the same regulatory gene.

opposable thumb: an anatomical arrangement in which the fleshy tip of the thumb can touch the fleshy tip of all the fingers.

order: a major division of a class, consisting of closely related families.

Oreopithecidae: specialized hominoid from the Late Miocene of Europe.

orthognathous: describes a face that is relatively vertical as opposed to being prognathous.

orthograde: vertical posture.

ossification: the process of bone formation.

osteodontokeratic culture: an archaeological culture based upon tools made of bone, teeth, and hoary.

osteology: the study of bones.

outgroup: in a cladistic analysis, a group of species that are closely related to the species being studied and are used to differentiate between shared derived and ancestral derived features.

ovulation: the point during the female reproductive cycle, usually the midpoint, when the ovum has matured and breaks through the wall of the ovary.

ovum: a female gamete.

paleoanthropology: the study of the fossil record and archaeology.

paleoecology: the study of the relationship of extinct organisms or groups of organisms to their environments.

paleoenvironments: past environmental/climatic conditions.

paleomagnetism: see archaeomagnetic dating.

paleontologists: experts on animal life of the distant past.

paleontology: that specialized branch of physical anthropology that analyzes the emergence and subsequent evolution of human physiology.

paleopathology: the study of the evidence of trauma and disease in fossilized skeletons.

paleospecies: a group of similar fossils whose range of morphological variation does not exceed the range of variation of a closely related living species.

palynology: the analysis of fossil pollen as an aid to the reconstruction of past vegetation and climates.

pangenesis: an early and inaccurate idea that acquired characteristics of parents are transmitted to their offspring.

Panidae: family within the superfamily Hominoidea that consists of the common chimpanzee, bonobo, and gorilla.

paradigmatic view: approach to science, developed by Thomas Kuhn, which holds that science develops from a set of assumptions (paradigm) and that revolutionary science ends with the acceptance of a new paradigm which ushers in a period of normal science.

parallel evolution: see parallelism.

parallelism: a condition in which homoplastic similarities are found in related species that did not exist in the common ancestor. However, the common ancestor provided initial commonalities that gave direction to the evolution of the similarities.

Parapithecoidea: suborder of the order Primates consisting of Early Oligocene primates from the Fayum, Egypt.

pedigree: a diagrammatic reconstruction of past mating in a family.

penetrance: the degree to which an allele is expressed in the phenotype.

pentadactylism: the presence of five digits on the hand and/or foot.

peptide bond: a link between amino acids in a protein.

pericentric inversion: a type of inversion in which two breaks occur in a chromosome, one on either side of the centromere, and the centerpiece becomes fumed around and rejoined with the two outside pieces.

period: a unit of geological time; a division of an era.

peripheralization: the process whereby an adolescent animal encounters aggressive behavior from adults and gradually moves away from the group over time.

permanent teeth The second set of teeth that erupt in mammals. Humans have thirty-two permanent teeth.

pH: The measurement of acidity or alkalinity. A pH of 7 is neutral; less than 7 is acid; greater than 7 is basic or alkaline.

phenotype: the observable and measurable characteristics of an organism.

phenylketonuria (PKU): a genetic disease, inherited as a recessive, brought about by the absence of the enzyme responsible for the conversion of the amino acid phenylalanine to tyrosine. Phenylalanine accumulates in the blood and then breaks down into by-products that cause severe mental retardation in addition to other symptoms.

phenylthiocarbamide (PTC): an artificially created substance whose main use is in detecting the ability to taste it. The ability to taste PTC is inherited as a dominant.

phosphate unit: a unit of the DNA molecule consisting of a phosphate and four oxygen atoms.

phyletic gradualism model: the idea that evolution is a slow process with gradual transformation of one population into another.

phylogenetic tree: a graphic representation of evolutionary relationships among animal species.

phylogeny: the evolutionary history of a species.

phylum: a major division of a kingdom, consisting of closely related classes; represents a basic body plan.

physical anthropology: the scientific study of the physical characteristics, variability, and evolution of the human organism.

physical environment: the complex of inanimate elements that surround an organism.

phytoliths: minute particles of silica derived from the cells of plants, able to survive alter the organism has decomposed or been burned. They are common in ash layers, pottery, and even on stone tools.

placenta: an organ that develops from fetal membranes and functions to pass oxygen, nutrients, and other substances to and waste material from the fetus.

placental mammals: members of the infraclass Eutheria of the class Mammalia; mammals that form a placenta.

placoderm: a member of the extinct class of early jawed vertebrates.

plasma membrane: a structure that binds the cell but allows for the entry and exit of certain substances.

plasma: the liquid portion of the blood containing salts, sugars, fats, amino acids, hormones, plasma, proteins, etc.

plate tectonics: the theory that the surface of the earth is divided into a number of plates that move in relationship to each other. Some of these plates carry the continents.

platelets: cell fragments in the blood that function in blood clotting.

platycephalic: having a low and relatively flat forehead.

platyrrhine nose: a nose in which the nostrils open sideways and are usually separated by a broad nasal septum; characteristic of the New World monkeys.

Platyrrhini: infraorder of the order Primates that includes the New World monkeys and various New World fossil taxa.

play group: a group of juveniles within a larger social unit that engage in play behavior.

play: energetic and repetitive activity engaged in primarily by infants and juveniles.

pleiotropy: a situation in which a single allele may affect an entire series of traits.

plesiomorphic: in cladistics, this term describes primitive or generalized characteristics that arose early in the evolutionary history of a taxonomic group. These will be very widespread and will therefore not help in dividing the group into lower-level taxa.

pneumatized: the presence of air spaces within some bones of the skull.

point mutation: an error at a particular point on the DNA molecule.

polar bodies: cells that develop in oogenesis, contain little cytoplasm, and do not develop into mature ova.

polygenic: the result of the interaction of several genes.

polymorphism: the presence of several distinct forms of a gene or phenotypic trait within a population with frequencies greater than 1 percent.

polypeptide: a chain of amino acids.

polyphyodonty: the continuous replacement of teeth such as occurs in reptiles.

polytypic: a situation in which a species is composed of several distinct populations.

Pongidae: family within the superfamily Hominoidea that consists of the orangutan.

populationist viewpoint: the concept that only individuals have reality and that the type is illusory. Since no two individuals are exactly alike, variation underlies all existence.

positive eugenics: a method of increasing the frequency of desirable traits by encouraging reproduction by individuals with these traits.

positivism: theoretical position that explanations must be empirically verifiable, that there are universal laws in the structure and transformation of human institutions, and that theories which incorporate individualistic elements, such as minds, are not verifiable.

post-partum sex taboo: the prohibition of a woman from having sexual intercourse for a specified period of time following the birth of a child.

postmating mechanism: any form of reproductive isolation that occurs after mating.

postorbital bar: a feature of the skull formed by a downward extension of the frontal bone that supports the eye.

postorbital constriction: as seen from the top view, a marked constriction in the skull immediately behind the orbits and supraorbital torus.

postorbital septum: a bony petition behind the eye that isolates the eye from the muscles of the jaw and forms a bony eye socket, or orbit, in which the eye lies.

potassium argon dating: a chronometric dating technique based on the rate of decay of potassium 40 to argon 40. Used to date rocks up to thousands of millions of years old though it is restricted to volcanic material no more recent than c 100 000 years old. One of the most widely used methods in the dating of early hominid sites in Africa.

power grip: a grip in which an object is held between the fingers and the palm with the thumb reinforcing the fingers.

preadaptation: the potential to adapt to a new niche.

precision handling: a situation in which an object is held between one or more fingers with the thumb fully opposed to the fingertips.

prehensile tail: a tail found in some New World monkeys that has the ability to grasp.

prehistoric: the period prior to written records for any given area. In North America synonymous with

prehistory: the period of human history before the advent of writing.

premating mechanism: a form of reproductive isolation that prevents mating from occurring.

prenatal: the period of an individual's life cycle from conception to birth.

presenting: a behavior in which a subordinate primate shows his or her anal region to a dominant animal.

preservation potential: the probability of a bone's being preserved after death.

primary center of ossification: the area of first appearance of bone within the cartilage model of a long bone.

Primates: order of the class Mammalia that includes the living prosimians, tarsiers, New World monkeys, Old World monkeys, lesser apes, great apes, and humans.

primatology: the study of living nonhuman primates.

prion: a microscopic particle that causes nervous system diseases in nonhuman animals and has been implicated as the cause of kuru. The prion appears to be composed of protein and lacks any nucleic acid.

Proconsulidae: Miocene hominoids from Africa.

prognathism: a jutting forward of the facial skeleton and jaws.

prokaryote: a cell, more primitive than a eukaryote, having no nucleus. Prokaryotes include bacteria and blue-green algae.

pronograde: a posture in which the body is held parallel to the ground.

Propliopithecidae: family of the infraorder Catarrhini from the Middle Oligocene to Late Miocene of Africa and Europe that may have given rise to the Old World monkeys and the hominoids.

prosimians: members of the suborder Prosimii, including the living Madagascar lemuriformes and the lorises, potto, angwantibo, and galagos.

Prosimii: suborder of the order Primates that includes the living Madagascar lemuriformes and the lorises, potto, angwantibo, and galagos.

protein-caloric malnutrition: a class of malnutrition that includes kwashiorkor and marasmus.

protein: a long chain of amino acids joined together by peptide bonds (a polypeptide chain).

protoculture: the simplest or beginning aspects of culture as seen in some nonhuman primates.

prototherian mammals: mammals belonging to the subclass Prototheria; monotremes or egg-laying mammals.

provisionized colony: groups of free-ranging primates that have become accustomed to humans because of the establishment of feeding stations.

proxemics: the study of human perception and use of space in communication and social relations.

psychological anthropology: the study of the relationship between culture and individual personality.

ptyalin: a digestive enzyme found in saliva that begins the digestion of starches in the mouth.

puberty: an event in the life cycle that includes rapid increase in stature, development of sex organs, and development of secondary sexual characteristics.

pubic symphysis: the area of the pelvis at which the two innominates join.

punctuated equilibria: principal feature of the evolutionary theory propounded by Niles Eldredge and Stephen J. Gould, in which species change is represented as a form of Darwinian gradualism "punctuated" by periods of rapid evolutionary change.

purine: a base found in nucleic acids that consists of two connected rings of carbon and nitrogen; in DNA and RNA, adenine and guanine.

pyrimidine: base found in nucleic acids that consists of a single ring of carbon and nitrogen; in DNA, thymine and cytosine, and in RNA, uracil and cytosine.

quadrupedalism: locomotion on four limbs.

race: a subgroup of human population that shares a greater number of physical traits with one another than they do with those of other subgroups.

radioactive decay: the regular process by which radioactive isotopes break down into their decay products with a half-life which is specific to the isotope in question (see also radiocarbon dating).

radiocarbon dating: an absolute dating method based on the radioactive decay of Carbon-14 contained in organic materials.

radiometric dating: a type of chronometric dating that involves methods based upon the decay of radioactive materials; examples are radiocarbon and potassium-argon dating.

random sample: a sample in which each individual in a population has the same chance of being selected as any other.

range: see home range.

recessive: a genetically determined characteristic that is expressed only in the homozygous recessive condition.

recombinant DNA: a technique for transferring genetic material from one organism to another.

recombination: a mechanism of meiosis responsible for each gamete's uniqueness. As the chromosomes line up in metaphase, they can combine into several configurations.

red blood cell: see erythrocyte.

refutationist view: approach which holds that science consists of theories about the empirical world, that its goal is to develop better theories, which is achieved by finding mistakes in existing theories, so that it is crucial that theories be falsifiable (vulnerable to error and open to testing). The approach, developed by Karl Popper, emphasizes the important of testability as a component of scientific theories.

regional continuity model: a hypothesis which states that modem H. sapiens had multiple origins from existing local populations. Each local population of archaic humans gave rise to a population of modem H. sapiens.

regulatory gene: a segment of DNA that functions to initiate or block the function of another gene.

relative fitness (RF): the fitness of a genotype compared with the fitness of another genotype in the same gene system. Relative fitness is measured on a scale of O to 1.

relativism: the concept that a cultural system can be viewed only in terms of the principles, background, frame of reference, and history that characterize it.

replacement model: a hypothesis which states that modern H. sapiens evolved in Africa or Asia and radiated out of one of these areas replacing archaic hominid populations.

repressor protein: the product of a regulatory gene that blocks the function of another gene.

reproductive isolating mechanism: a mechanism that prevents reproduction from occurring between two populations.

reproductive population: a group of organisms capable of successful reproduction.

reproductive risk: a measure expressed in terms of the number of zygotes needed from a mating pair to produce two offspring that will in turn reproduce.

research design: systematic planning of research, usually including (1) the formulation of a strategy to resolve a particular question; (2) the collection and recording of the evidence; (3) the processing and analysis of these data and their interpretation; and (4) the publication of results.

residual volume: the amount of air still remaining in the lungs after the most forceful expiration.

restriction enzyme: an enzyme used to "cut" the DNA molecule at specific sites; used in recombinant DNA technology.

retina: the layer of cells in the back of the eye that contains two types of cells, rods and cones, that are sensitive to light.

retinoblastoma: a cancer of the retina of the eye in children, inherited as a dominant.

Rh blood-type system: a blood-type system consisting of two major alleles. A mating between an Rh - mother and Rh + father may produce in the infant the hemolytic disease erythroblastosis fetalis.

rhinarium: the moist naked area surrounding the nostrils in most mammals; absent in most primates.

ribonucleic acid A type of nucleic acid based upon the sugar ribose; exists in cells as messenger RNA and transfer RNA.

ribose: a five-carbon sugar found in RNA.

ribosome: a small, spherical body within the cytoplasm of the cell in which protein synthesis takes place.

rods: cells of the retina of the eye that are sensitive to the presence or absence of light; function in black-and-white vision. ~

sagittal crest: a ridge of bone along the midline of the top of the skull that serves for the attachment of the temporalis muscle.

sagittal keel: a bony ridge formed by a thickening of bone along the top of the skull; characteristic of H. erectus.

sampling bias: the tendency of a sample to exclude some members of the sampling universe and overrepresent others.

sampling error: in population genetics, the transmission of a nonrepresentative sample of the gene pool over space or time due to chance. See also founder principle and genetic drift.

sampling unit: the sub-element of the total population selected for sampling.

sampling universe: the largest entity to be described, of which the sample is a part.

sampling: the probabilistic, systematic, or judgmental selection of a sub-element from a larger population, with the aim of approximating a representative picture of the whole.

scent marking: marking territory by urinating or defecating or by rubbing scent glands against trees or other objects.

science: a method of reaming about the world by applying the principles of the scientific method, which includes making empirical observations, proposing hypotheses to explain those observations, and testing those hypotheses in valid and reliable ways; also refers to the organized body of knowledge that results from scientific study.

scientific theory: a statement that postulates ordered relationships among natural phenomena.

scientism: the belief that there is one and only one method of science and that it alone confers legitimacy upon the conduct of research.

seasonal isolation: a form of reproductive isolation in which the breeding seasons of two closely related populations do not exactly correspond.

secondary center of ossification: an area of ossification, usually near the end of a long bone.

secondary sexual characteristics: physical features other than the genitalia that distinguish males from females after puberty.

sectorial premolar: a unicuspid first lower premolar with a shearing edge.

secular trend: the tendency over the last hundred or so years for each succeeding generation to mature earlier and become, on the average, larger.

sediment: material that was suspended in water and that settles at the bottom of a body of water.

sedimentary beds: beds, or layers, of sediments; also called strata.

sedimentation: the accumulation of geological or organic material deposited by air, water, or ice.

segregation: in the formation of sex cells, the process in which paired hereditary factors separate, forming sex cells that contain either one or the other factor.

selective agent: any factor that brings about differences in fertility and mortality.

selective coefficient: a numerical expression of the strength of a selective force operating on a specific genotype.

selective pressure: pressure placed by a selective agent upon certain individuals within the population that results in the change of allele frequencies in the next generation.

senescence: old age.

serum: plasma after the clotting material has settled out.

sex chromosomes: the X and Y chromosomes. Normal males have one X and one Y; normal females have two X's.

sex-controlled trait: a trait that is expressed differently in males and females.

sex-limited trait: a trait that is expressed in only one of the sexes.

sexual dimorphism: the condition in which differences in structure exist between males and females of the same species.

sexual division of labor: the situation in which males and females in a society perform different tasks. In hunting-gathering societies males usually hunt while females usually gather wild vegetable food.

sexual isolation: a form of reproductive isolation in which one or both sexes of a species initiate mating behavior that does not act as a stimulus to the opposite sex of a closely related species.

sexual skin: skin in the anal region that turns bright pink or red and may swell when the animal is in estrus; found in the female of some primate species.

shared ancestral feature: compared with a shared derived feature, a homology that did not appear as recently and is therefore shared by a larger group of species.

shared derived feature: a recently appearing homology that is shared by a relatively small group of closely related taxa.

sharing clusters: among chimpanzees, temporary groups that form after hunting to eat the meat.

shell midden: a site formed of mainly concentrated shellfish remains.

shovel-shaped incisors: incisors that have a scooped out shape on the tongue side of the tooth.

sickle-cell anemia: a disorder in individuals homozygous for hemoglobin S in which red blood cells will develop into a sickle shape that, in turn, will clog capillaries, resulting in anemia, heart failure, etc.

sickle-cell trait: the condition of being heterozygous for hemoglobin A and S. yet the individual usually shows no abnormal symptoms.

silent areas: sections of the cerebral cortex, which include parts of the frontal, occipital, and temporal lobes, in which electrical stimulation produces little or no emotional or motor response.

simian shelf: a bony buttress on the inner surface of the foremost part of the ape mandible, functioning to reinforce the mandible.

site: a distinct spatial clustering of artifacts, features, structures, and organic and environmental remains. as the residue of human activity.

social anthropology: see cultural anthropology. <> social category: a category composed of all people who share certain culturally identified characteristics.

social intelligence: the knowledge and images that originate in an individual's brain and that are transferred by speech land in the last 5,000 years, by writing to the brains of others.

society: a group of interacting people who share a geographical region, a sense of common identity, and a common culture.

sociobiology: the study of the biological control of social behavior.

sociocultural anthropology: a branch of anthropology that deals with variations in patterns of social interaction and differences in cultural behavior.

sociolinguistics: a branch of anthropological linguistics that studies how language and culture are related and how language is used in different social contexts.

somatic: a term that refers to the body.

specialized species: a species closely fit to a specific environment and able to tolerate little change in that environment.

specialized trait: a structure used basically for one function.

speciation: the evolutionary process that is said to occur when two previous subspecies (of the same species) are no longer capable of successful interbreeding; they are then two different species.

species: the largest natural population whose members are able to reproduce successfully among

sperm: a male gamete.

spermatogenesis: sperm production.

spindle: a structure consisting of fibers radiating out from the centriole that functions in cell division.

spontaneous generation: an old and incorrect idea that complex life forms could be spontaneously created from nonliving material.

standard deviation: a statistical measurement of the amount of variation in a series of determinations; the probability of the real number's falling within plus or minus one standard deviation is 67 percent.

statistical analysis: the application of probability theory to quantified descriptive data.

stereoscopic vision: visual perception of depth due to overlapping visual fields and various neurological features.

strata: (1) depositional units or layers of sediment distinguished by composition or appearance. (singular: "stratum"), (2) individually sampled subareas in a "stratified-random" probabilistic sampling scheme.

stratigraphy: the study and validation of stratification; the analysis in the vertical, time dimension, of a series of layers in the horizontal, space dimension. It is often used as a relative dating technique to assess the temporal sequence of artifact deposition.

stratosphere: the part of the atmosphere 20 to 50 kilometers (12 to 31 miles) above the earth's surface; the area where ozone forms.

structural gene: a segment of DNA that codes for a polypeptide other than a regulator.

subcutaneous fat: the fat deposited under the skin.

subera: a division of an era. The Cenozoic is divided into two suberas, the Tertiary and Quatemary.

submetacentric chromosome: a chromosome in which the centromere lies to one side of the center, producing arms of unequal length.

subspecies: interfertile groups within a species that display significant differentiation among themselves.

superposition: the principle that under stable conditions strata on the bottom of a deposit were laid down first and hence are older than layers on top.

suspensory behavior: a form of locomotion and posture whereby animals suspend themselves underneath a branch.

sweating: the production of a fluid, sweat, by the sweat glands of the skin. The evaporation of the sweat from the skin leads to a cooling of the body.

symbol: something that can represent something distant from it in time and space.

sympatric species: different species that live in the same area but are prevented from successfully re-producing by a reproductive isolating mechanism.

symphyseal face: the surface of the pubis where one pubis joins the other at the pubic symphysis.

symplesiomorphic feature: see shared ancestral feature.

synapomorphic feature: see shared derived feature.

synapsids: the reptilian group from which the mammals ultimately emerged.

syndrome: a complex of symptoms related to a single cause.

synostosis: the joining of separate pieces of bone in human skeletons; the precise timing of such processes is an important indicator of age.

synthetic theory of evolution: the theory of evolution that fuses Darwin's concept of natural selection with information from the fields of genetics, mathematics, embryology, paleontology, animal behavior, and other disciplines.

system: a series of interrelated parts wherein a change in one part brings about changes in all parts.

systematic sampling: a form of probabilistic sampling employing a grid of equally spaced locations; e.g. selecting every other square. This method of regular spacing runs the risk of missing (or hitting) every single example if the distribution itself is regularly spaced.

tactile pads: the tips of the fingers and toes of primates; area richly endowed by tactile nerve endings sensitive to touch.

taphonomy: the study of processes which have affected organic materials such as bone after death; it also involves the microscopic analysis of tooth-marks or cut marks to assess the effects of butchery or scavenging activities.

Tarsiidae: suborder of the order Primates consisting of the tarsiers.

taxon: a group of organisms at any level of the taxonomic hierarchy. The major taxa are the species and genus and the higher taxa, including the family, order, class, phylum, and kingdom.

taxonomy: the theory of classification.

Tay-Sachs disease: an enzyme deficiency of lipid metabolism inherited as