Physical Anthropology

An anatomical, physiological, or behavioral response of organisms or populations to the environment. Adaptations result from evolutionary change (specifically, as a result of natural selection).

The field of inquiry that studies human culture and evolutionary aspects of human biology; includes cultural anthropology, archaeology, linguistics, and physical, or biological, anthropology.

applied anthropology
The practical application of anthropological and archaeological theories and techniques. For example, many biological anthropologists work in the public health sector.

Objects or materials made or modified for use by hominins. The earliest artifacts are usually tools made of stone or, occasionally, bone.

Anything organisms do that involves action in response to internal or external stimuli; the response of an individual, group, or species to its environment. Such responses may or may not be deliberate, and they aren’t necessarily the result of conscious decision-making (which is absent in single-celled organisms, insects, and many other species).

The study of skeletal remains from archaeological sites.

biocultural evolution
The mutual, interactive evolution of human biology and culture; the concept that biology makes culture possible and that developing culture further influences the direction of biological evolution; a basic concept in understanding the unique components of human evolution.

On two feet; walking habitually on two legs.

A set of relationships in which all components fall along a single integrated spectrum (for example, color). All life reflects a single biological continuum.

Behavioral aspects of human adaptation, including technology, traditions, language, religion, marriage patterns, and social roles. Culture is a set of learned behaviors transmitted from one generation to the next by nonbiological (i.e., nongenetic) means.

data (sing., datum)
Facts from which conclusions can be drawn; scientific information.

DNA (deoxyribonucleic acid)
The double-stranded molecule that contains the genetic code. DNA is a main component of chromosomes.

Relying on experiment or observation; from the Latin empiricus, meaning “experienced.”

Viewing other cultures from the inherently biased perspective of one’s own culture. Ethnocentrism often results in other cultures being seen as inferior to one’s own.

Detailed descriptive studies of human societies. In cultural anthropology, an ethnography is traditionally the study of a non-Western society.

A change in the genetic structure of a population. The term is also frequently used to refer to the appearance of a new species.

forensic anthropology
An applied anthropological approach dealing with legal matters. Forensic anthropologists work with coroners and others in identifying and analyzing human remains.

Having to do with the study of gene structure and action and the patterns of inheritance of traits from parent to offspring. Genetic mechanisms are the foundation for evolutionary change.

Colloquial term for members of the evolutionary group that includes modern humans and now extinct bipedal relatives.

hypotheses (sing., hypothesis)
A provisional explanation of a phenomenon. Hypotheses require verification or falsification through testing.

The study of skeletal material. Human osteology focuses on the interpretation of the skeletal remains from archaeological sites, skeletal anatomy, bone physiology, and growth and development. Some of the same techniques are used in paleoanthropology to study early hominins.

The interdisciplinary approach to the study of earlier hominins—their chronology, physical structure, archaeological remains, habitats, and so on.

The branch of osteology that studies the evidence of disease and injury in human skeletal (or, occasionally, mummified) remains from archaeological sites.

Members of the mammalian order Primates (pronounced “pry-may´- tees”), which includes lemurs, lorises, tarsiers, monkeys, apes, and humans.

The study of the biology and behavior of nonhuman primates (lemurs, lorises, tarsiers, monkeys, and apes).

Using all four limbs to support the body during locomotion; the basic mammalian (and primate) form of locomotion.

Pertaining to measurements of quantity and including such properties as size, number, and capacity. When data are quantified, they’re expressed numerically and can be tested statistically.

Viewing entities as they relate to something else. Cultural relativism is the view that cultures have merits within their own historical and environmental contexts.

(also spelled savannah) A large flat grassland with scattered trees and shrubs. Savannas are found in many regions of the world with dry and warm-to-hot climates.

A body of knowledge gained through observation and experimentation; from the Latin scientia, meaning “knowledge.”

scientific method
An approach to research whereby a problem is identified, a hypothesis (provisional explanation) is stated, and that hypothesis is tested by collecting and analyzing data.

scientific testing
The precise repetition of an experiment or expansion of observed data to provide verification; the procedure by which hypotheses and theories are verified, modified, or discarded.

A group of organisms that can interbreed to produce fertile offspring. Members of one species are reproductively isolated from members of all other species (i.e., they cannot mate with them to produce fertile offspring).

A broad statement of scientific relationships or underlying principles that has been substantially verified through the testing of hypotheses.

General cultural orientation or perspective shared by members of a society.

binomial nomenclature (binomial, meaning “two names”)
In taxonomy, the convention established by Carolus Linnaeus whereby genus and species names are used to refer to species. For example, Homo sapiens refers to human beings.

biological continuity
A biological continuum. When expressions of a phenomenon continuously grade into one another so that there are no discrete categories, they exist on a continuum. Color is one such phenomenon, and life-forms are another.

The view that the earth’s geological landscape is the result of violent cataclysmic events. Cuvier promoted this view, especially in opposition to Lamarck.

Christian fundamentalists
Adherents to a movement in American Protestantism that began in the early twentieth century. This group holds that the teachings of the Bible are infallible and that the scriptures are to be taken literally.

The ability to conceive and produce healthy offspring.

Pertaining to natural selection, a measure of the relative reproductive success of individuals. Fitness can be measured by an individual’s genetic contribution to the next generation compared with that of other individuals. The terms genetic fitness, reproductive fitness, and differential reproductive success are also used.

fixity of species
The notion that species, once created, can never change; an idea diametrically opposed to theories of biological evolution.

The entire genetic makeup of an individual or species.

natural selection
The most critical mechanism of evolutionary change, first described by Charles Darwin; refers to genetic change or changes in the frequencies of certain traits in populations due to differential reproductive success between individuals.

reproductive success
The number of offspring an individual produces and rears to reproductive age; an individual’s genetic contribution to the next generation.

reproductively isolated
Pertaining to groups of organisms that, mainly because of genetic differences, are prevented from mating and producing offspring with members of other such groups. For example, dogs cannot mate and produce offspring with cats.

selective pressures
Forces in the environment that influence reproductive success in individuals.

The branch of science concerned with the rules of classifying organisms on the basis of evolutionary relationships.

The theory that the earth’s features are the result of long-term processes that continue to operate in the present just as they did in the past. Elaborated on by Lyell, this theory opposed catastrophism and contributed strongly to the concept of immense geological time.

amino acids
Small molecules that are the components of proteins.

All chromosomes except the sex chromosomes.

Discrete structures composed of DNA and proteins found only in the nucleus of cells. Chromosomes are visible under magnification only during certain phases of cell division.

Organisms that are genetically identical to another organism.

Triplets of messenger RNA bases that code for specific amino acids during protein synthesis.

In genetics, referring to the fact that DNA bases form pairs (called base pairs) in a precise manner. For example, adenine can bond only to thymine. These two bases are said to be complementary because one requires the other to form a complete DNA base pair.

The semifluid substance contained within the cell membrane. The nucleus and numerous other kinds of structures involved with cell function are found within the cytoplasm.

DNA (deoxyribonucleic acid)
The double-stranded molecule that contains the genetic code. DNA is a main component of chromosomes.

Specialized proteins that initiate and direct chemical reactions in the body.

Segments of genes that are transcribed and are involved in protein synthesis. (The prefix ex denotes that these segments are expressed.)

Reproductive cells (eggs and sperm in animals) developed from precursor cells in ovaries and testes.

A sequence of DNA bases that specifies the order of amino acids in an entire protein, a portion of a protein, or any functional product (e.g., RNA). A gene may be made up of hundreds or thousands of DNA bases organized into coding and noncoding segments.

The entire genetic makeup of an individual or species.

A protein molecule that occurs in red blood cells and binds to oxygen molecules.

homeobox genes
An evolutionarily ancient group of regulatory genes. One type (called Hox genes) directs segmentation of the body during embryonic development.

Substances (usually proteins) that are produced by specialized cells and that travel to other parts of the body, where they influence chemical reactions and regulate various cellular functions.

Human Genome Project
An international effort aimed at sequencing and mapping the entire human genome, completed in 2003.

Segments of genes that are initially transcribed and then deleted. Because they aren’t expressed, they aren’t involved in protein synthesis. However, a DNA sequence that is deleted during the manufacture of one protein may not be deleted in another. Therefore, the terms “introns” and “noncoding DNA” aren’t synonymous.

Cell division in specialized cells in ovaries and testes. Meiosis involves two divisions and results in four daughter cells, each containing only half the original number of chromosomes. These cells can develop into gametes.

messenger RNA (mRNA)
A form of RNA that’s assembled on a sequence of DNA bases. It carries the DNA code to the ribosome during protein synthesis.

mitochondria (sing., mitochondrion)
Structures contained within the cytoplasm of eukaryotic cells that convert energy, derived from nutrients, to a form that can be used by the cell.

mitochondrial DNA (mtDNA)
DNA found in the mitochondria. Mitochondrial DNA is inherited only from the mother.

Simple cell division; the process by which somatic cells divide to produce two identical daughter cells.

Structures made up of two or more atoms. Molecules can combine with other molecules to form more complex structures.

A change in DNA. The term can refer to changes in DNA bases (specifically called point mutations) as well as to changes in chromosome number and/or structure.

noncoding DNA
DNA that does not direct the production of proteins. However, such DNA segments may produce other important molecules, so the term noncoding DNA is not really accurate.

Basic units of the DNA molecule, composed of a sugar, a phosphate, and one of four DNA bases.

A structure (organelle) found in all eukaryotic cells. The nucleus contains DNA that, during cell division, is organized into chromosomes.

polymerase chain reaction (PCR)
A method of producing thousands of copies of a DNA sample.

protein synthesis
The manufacture of proteins; the assembly of chains of amino acids into functional protein molecules. Protein synthesis is directed by DNA.

Three-dimensional molecules that serve a wide variety of functions through their ability to bind to other molecules.

The exchange of genetic material between paired chromosomes during meiosis; also called crossing over.

regulatory genes
Genes that influence the activity of other genes. Regulatory genes direct embryonic development and are involved in physiological processes throughout life. They are extremely important to the evolutionary process.

To duplicate. The DNA molecule is able to make copies of itself.

Structures composed of a form of RNA called ribosomal RNA (rRNA) and protein. Ribosomes are found in a cell’s cytoplasm and are essential to the manufacture of proteins.

RNA (ribonucleic acid)
A single-stranded molecule similar in structure to DNA. Three forms of RNA are essential to protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA).

sex chromosomes
In mammals, the X and Y chromosomes.

somatic cells
Basically, all the cells in the body except those involved with reproduction.

transfer RNA (tRNA)
The form of RNA that binds to specific amino acids and transports them to the ribosome during protein synthesis.

A cell formed by the union of an egg cell and a sperm cell. It contains the full complement of chromosomes (in humans, 46) and has the potential to develop into an entire organism.

allele frequency
In a population, the percentage of all the alleles at a locus accounted for by one specific allele.

Alternate forms of a gene. Alleles occur at the same locus on both members of a pair of chromosomes, and they influence the same trait. But because they’re slightly different from one another, their action may result in different expressions of that trait. The term allele is sometimes used synonymously with gene.

Large molecules found on the surface of cells. Several different loci govern various antigens on red and white blood cells. (Foreign antigens provoke an immune response.)

The expression of two alleles in heterozygotes. In this situation, neither allele is dominant or recessive, so they both influence the phenotype.

In genetics, describing a trait governed by an allele that’s expressed in the presence of another allele (that is, in heterozygotes). Dominant alleles prevent the expression of recessive alleles in heterozygotes. (This is the definition of complete dominance.)

founder effect
A type of genetic drift in which allele frequencies are altered in small populations that are taken from, or are remnants of, larger populations.

gene flow
Exchange of genes between populations.

gene pool
All of the genes shared by the reproductive members of a population.

genetic drift
Evolutionary changes, or changes in allele frequencies, that are produced by random factors in small populations. Genetic drift is a result of small population size.

The genetic makeup of an individual. Genotype can refer to an organism’s entire genetic makeup or to the alleles at a particular locus.

Having different alleles at the same locus on members of a pair of chromosomes.

Having the same allele at the same locus on both members of a pair of chromosomes.

Offspring of parents who differ from each other with regard to certain traits or certain aspects of genetic makeup; heterozygotes.

locus (pl., loci) (lo-kus, lo-sigh)
The position on a chromosome where a given gene occurs. The term is frequently used interchangeably with gene.

Changes produced only after many generations, such as the appearance of a new species.

Mendelian traits
Characteristics that are influenced by alleles at only one genetic locus. Examples include many blood types, such as ABO. Many genetic disorders, including sickle-cell anemia and Tay-Sachs disease, are also Mendelian traits.

Small changes occurring within species, such as changes in allele frequencies.

The observable or detectable physical characteristics of an organism; the detectable expressions of genotypes, frequently influenced by environmental factors.

In this context, a molecule that influences the color of skin, hair, and eyes.

Referring to traits that are influenced by genes at two or more loci. Examples include stature, skin color, eye color, and hair color. Many (but not all) polygenic traits are influenced by environmental factors such as nutrition and exposure to sunlight.

Within a species, a community of individuals where mates are usually found.

principle of independent assortment
The distribution of one pair of alleles into gametes does not influence the distribution of another pair. The genes controlling different traits are inherited independently of one another.

principle of segregation
Genes (alleles) occur in pairs because chromosomes occur in pairs. During gamete formation, the members of each pair of alleles separate, so that each gamete contains one member of each pair.

random assortment
The chance distribution of chromosomes to daughter cells during meiosis. Along with recombination, random assortment is an important source of genetic variation (but not new alleles).

Describing a trait that isn’t expressed in heterozygotes; also refers to the allele that governs the trait. For a recessive allele to be expressed, an individual must have two copies of it (that is, the individual must be homozygous).

selective breeding
A practice whereby animal or plant breeders choose which individual animals or plants will be allowed to mate based on the traits (such as body size) they hope to produce in the offspring. Animals or plants that don’t have the desirable traits aren’t allowed to breed.

sickle-cell anemia
A severe inherited hemoglobin disorder in which red blood cells collapse when deprived of oxygen. It results from inheriting two copies of a mutant allele. This allele is caused by a single base substitution in the DNA.

sickle-cell trait
Heterozygous condition in which a person has one HbA allele and one HbS allele. Thus they have some normal hemoglobin.

In genetics, inherited differences among individuals; the basis of all evolutionary change.

adaptive radiation
The relatively rapid expansion and diversification of life-forms into new ecological niches.

Similarities between organisms based strictly on common function, with no assumed common evolutionary descent.

Referring to characters inherited by a group of organisms from a remote ancestor and thus not diagnostic of groups (lineages) that diverged after the character first appeared; also called primitive.

biological species concept
A depiction of species as groups of individuals capable of fertile interbreeding but reproductively isolated from other such groups.

The phylum of the animal kingdom that includes vertebrates.

A group of organisms sharing a common ancestor. The group includes the common ancestor and all descendants.

An approach to classification that attempts to make rigorous evolutionary interpretations based solely on analysis of certain types of homologous characters (those considered to be derived characters).

A chart showing evolutionary relationships as determined by cladistic analysis. It’s based solely on interpretation of shared derived characters. It contains no time component and does not imply ancestor-descendant relationships.

In biology, the ordering of organisms into categories, such as orders, families, and genera, to show evolutionary relationships.

continental drift
The movement of continents on sliding plates of the earth’s surface. As a result, the positions of large landmasses have shifted drastically during the earth’s history.

derived (modified)
Referring to characters that are modified from the ancestral condition and thus diagnostic of particular evolutionary lineages.

ecological niche
The position of a species within its physical and biological environments. A species’ ecological niche is defined by such components as diet, terrain, vegetation, type of predators, relationships with other species, and activity patterns, and each niche is unique to a given species. Together, ecological niches make up an ecosystem.

endothermic (endo, meaning “within” or “internal”)
Able to maintain internal body temperature by producing energy through metabolic processes within cells; characteristic of mammals, birds, and perhaps some dinosaurs.

Categories of the geological time scale; subdivisions of periods. In the Cenozoic era, epochs include the Paleocene, Eocene, Oligocene, Miocene, and Pliocene (from the Tertiary Period) and the Pleistocene and Holocene (from the Quaternary Period).

evolutionary systematics
A traditional approach to classification (and evolutionary interpretation) in which presumed ancestors and descendants are traced in time by analysis of homologous characters.

Traces or remnants of organisms found in geological beds on the earth’s surface.

genus (pl., genera)
A group of closely related species.

geological time scale
The organization of earth history into eras, periods, and epochs; commonly used by geologists and paleoanthropologists.

Having different kinds of teeth; characteristic of mammals, whose teeth consist of incisors, canines, premolars, and molars.

Similarities between organisms based on descent from a common ancestor.

homoplasy (homo, meaning “same,” and plasy, meaning “growth”)
The separate evolutionary development of similar characteristics in different groups of organisms.

Between species; refers to variation beyond that seen within the same species to include additional aspects seen between two different species.

Within species; refers to variation seen within the same species.

The process in which parts of animals (or some plants) become transformed into stone-like structures. Mineralization usually occurs very slowly as water carrying minerals, such as silica or iron, seeps into the tiny spaces within a bone. In some cases, the original minerals within the bone or tooth can be completely replaced, molecule by molecule, with other minerals.

Species defined from fossil evidence, often covering a long time span.

phylogenetic tree
A chart showing evolutionary relationships as determined by evolutionary systematics. It contains a time component and implies ancestor- descendant relationships.

A type (subclass) of mammal. During the Cenozoic, placentals became the most widespread and numerous mammals and today are represented by upward of 20 orders, including the primates.

sexual dimorphism
Differences in physical characteristics between males and females of the same species. For example, humans are slightly sexually dimorphic for body size, with males being taller, on average, than females of the same population. Sexual dimorphism is very pronounced in many species, such as gorillas.

shared derived
Relating to specific character traits shared in common between two life-forms and considered the most useful type of characteristic for making evolutionary interpretations.

The process by which a new species evolves from an earlier species. Speciation is the most basic process in macroevolution.

The study of how bones and other materials come to be buried in the earth and preserved as fossils.

Animals with segmented, bony spinal columns; includes fishes, amphibians, reptiles (including birds), and mammals.

adaptive niche
An organism’s entire way of life: where it lives, what it eats, how it gets food, how it avoids predators, and so on.

Members of a suborder of Primates, the infraorder Anthropoidea (pronounced “an-throw-poid´-ee-uh”). Traditionally, the suborder includes monkeys, apes, and humans.

Tree-living; adapted to life in the trees.

binocular vision
Vision characterized by overlapping visual fields provided by forward-facing eyes. Binocular vision is essential to depth perception.

Arm swinging, a form of locomotion used by some primates. Brachiation involves hanging from a branch and moving by alternately swinging from one arm to the other.

cercopithecines (serk-oh-pith´-ehseens)
The subfamily of Old World monkeys that includes baboons, macaques, and guenons.

colobines (kole´-uh-bines)
Common name for members of the subfamily of Old World monkeys that includes the African colobus monkeys and Asian langurs.

The bumps on the chewing surface of premolars and molars.

dental formula
Numerical device that indicates the number of each type of tooth in each side of the upper and lower jaws.

Active during the day.

Period of sexual receptivity in female mammals (except humans), correlated with ovulation. When used as an adjective, the word is spelled “estrous.”

frugivorous (fru-give´-or-us)
Having a diet composed primarily of fruit.

Haplorhini (hap’-lo-rin-ee)
The primate suborder that includes tarsiers, monkeys, apes, and humans.

The two halves of the cerebrum that are connected by a dense mass of fibers. (The cerebrum is the large rounded outer portion of the brain.)

Members of the primate superfamily (Hominoidea) that includes apes and humans.

Mental capacity; ability to learn, reason, or comprehend and interpret information, facts, relationships, and meanings; the capacity to solve problems, whether through the application of previously acquired knowledge or through insight.

ischial callosities
Patches of tough, hard skin on the buttocks of Old World monkeys and chimpanzees.

natal group
The group in which an animal is born and raised. (Natal pertains to birth.)

The more recently evolved portion of the brain that is involved in higher mental functions and composed of areas that integrate incoming information from different sensory organs.

Active during the night.

The sense of smell.

Having a diet consisting of many kinds of food including plants, meat, and insects.

Members of the mammalian order Primates (pronounced “pry-may´- tees”), which includes lemurs, lorises, tarsiers, monkeys, apes, and humans.

Using all four limbs to support the body during locomotion; the basic mammalian (and primate) form of locomotion.

rhinarium (rine-air´-ee-um) (Plural: rhinaria)
The moist, hairless pad at the end of the nose seen in most mammalian species. The rhinarium enhances an animal’s ability to smell.

sensory modalities
Different forms of sensation (e.g., touch, pain, pressure, heat, cold, vision, taste, hearing, and smell).

sexual dimorphism
Differences in physical characteristics between males and females of the same species. For example, humans are slightly sexually dimorphic for body size, with males being taller, on average, than females of the same population.

stereoscopic vision
The condition whereby visual images are, to varying degrees, superimposed. This provides for depth perception, or viewing the external environment in three dimensions. Stereoscopic vision is partly a function of structures in the brain.

Strepsirhini (strep’-sir-in-ee)
The primate suborder that includes lemurs and lorises.

Pertaining to the protection of all or a part of the area occupied by an animal or group of animals. Territorial behaviors range from scent marking to outright attacks on intruders.

affiliative behaviors
Amicable associations between individuals. Affiliative behaviors, such as grooming, reinforce social bonds and promote group cohesion.

Behavior that benefits another individual but at some potential risk or cost to oneself.

Viewing nonhuman organisms in terms of human experience and capabilities. Emphasizing the importance of humans over everything else.

Pertaining to physiological responses not under voluntary control. An example in chimpanzees would be the erection of body hair during excitement. Blushing is a human example. Both convey information regarding emotional states, but neither is deliberate, and communication isn’t intended.

Anything organisms do that involves action in response to internal or external stimuli. The response of an individual, group, or species to its environment. Such responses may or may not be deliberate and they aren’t necessarily the results of conscious decision making.

behavioral ecology
The study of the evolution of behavior, emphasizing the role of ecological factors as agents of natural selection. Behaviors and behavioral patterns have been favored because they increase the reproductive fitness of individuals (i.e., they are adaptive) in specific environmental contexts.

biological continuum
Refers to the fact that organisms are related through common ancestry and that behaviors and traits seen in one species are also seen in others to varying degrees. (When expressions of a phenomenon continuously grade into one another so that there are no discrete categories, they are said to exist on a continuum. Color is such a phenomenon.)

Any act that conveys information, in the form of a message, to another individual. Frequently, the result of communication is a change in the behavior of the recipient. Communication may not be deliberate but may instead be the result of involuntary processes or a secondary consequence of an intentional action.

core area
The portion of a home range containing the highest concentration and most reliable supplies of food and water. The core area is defended.

Sequences of repetitious behaviors that serve to communicate emotional states. Nonhuman primate displays are most frequently associated with reproductive or agonistic behavior and examples include chest slapping in gorillas or, in male chimpanzees, dragging and waving branches while charging and threatening other animals.

dominance hierarchies
Systems of social organization wherein individuals within a group are ranked relative to one another. Higher-ranking animals have greater access to preferred food items and mating partners than lower-ranking individuals. Dominance hierarchies are sometimes called “pecking orders.”

Pertaining to the relationships between organisms and all aspects of their environment (temperature, predators, nonpredators, vegetation, availability of food and water, types of food, disease organisms, parasites, etc.).

The ability to identify with the feelings and thoughts of another individual.

Period of sexual receptivity in nonhuman female mammals correlated with ovulation. When used as an adjective, it is spelled “estrous.”

Picking through fur to remove dirt, parasites, and other materials that may be present. Social grooming is common among primates and reinforces social relationships.

Within the group as opposed to intergroup (meaning between groups).

Pertaining to K-selection, an adaptive strategy whereby individuals produce relatively few offspring, in whom they invest increased parental care. Although only a few infants are born, chances of survival are increased for each one because of parental investments in time and energy. Birds, elephants, and canids (wolves, coyotes, and dogs) are examples of K-selected nonprimate species.

A standardized system of arbitrary vocal sounds, written symbols, and gestures used in communication.

life history traits
Characteristics and developmental stages that influence reproductive rates. Examples include longevity, age at sexual maturity, length of time between births, etc.

Groups that consist of a female, her daughters, and their offspring. Matrilineal groups are common in macaques.

The chemical processes within cells that break down nutrients and release energy for the body to use. (When nutrients are broken down into their component parts, such as amino acids, energy is released and made available for the cell to use.)

A mating system wherein a female cotinuously associates with more than one male (usually two or three) with whom she mates. Among nonhuman primates, polyandry is seen only in marmosets and tamarins. It also occurs in a few human societies.

Pertaining to polygeny. A mating system in which males, and in some cases females, have several mating partners.

Pertaining to r-selection, a reproductive strategy that emphasizes relatively large numbers of offspring and reduced parental care compared to K-selected species. K-selection and r-selection are relative terms; e.g., mice are r-selected compared to primates but K-selected compared to fish.

reproductive strategies
Behaviors or behavioral complexes that have been favored by natural selection to increase individual reproductive success. The behaviors need not be deliberate, and they often vary considerably between males and females.

sexual selection
A type of natural selection that operates on only one sex within a species. It’s the result of competition for mates, and it can lead to sexual dimorphism with regard to one or more traits.

social structure
The composition, size, and sex ratio of a group of animals. The social structure of a species is, in part, the result of natural selection in a specific habitat, and it guides individual interactions and social relationships.

Portions of an individual’s or group’s home range that are actively defended against intrusion, especially by members of the same species.

Objects or materials made or modified for use by hominins. The earliest artifacts tend to be made of stone or occasionally bone.

A colloquial name referring to a diverse group of Plio-Pleistocene African hominins. Australopiths are the most abundant and widely distributed of all early hominins and are also the most completely studied.

Pertaining to the concept that biology makes culture possible and that culture influences biology.

bipedal locomotion
Walking on two feet. Walking on two legs is the single most distinctive feature of the hominins.

chronometric (chronos, meaning “time,” and metric, meaning “measure”)
Referring to a dating technique that gives an estimate in actual numbers of years.

Nonbiological adaptations to the environment. This includes learned behaviors that can be communicated to others—especially from one generation to the next. Aspects of this capacity have been identified in our closest ape relatives.

Referring to animal remains; in archaeology, specifically refers to the fossil (skeletonized) remains of animals.

habitual bipedalism
Bipedal locomotion as the form of locomotion shown by hominins most of the time.

Colloquial term for members of the tribe Hominini, which includes all bipedal hominoids back to the divergence with African great apes.

honing complex
The shearing of a large upper canine with the 1st lower premolar, with the wear leading to honing of the surfaces of both teeth. This anatomical pattern is typical of most Old World anthropoids, but is mostly absent in hominins.

large-bodied hominoids
Those hominoids including the great apes (orangutans, chimpanzees, gorillas) and hominins, as well as all ancestral forms back to the time of divergence from small-bodied hominoids (i.e., the gibbon lineage).

mosaic evolution
A pattern of evolution in which the rate of evolution in one functional system varies from that in other systems. For example, in hominin evolution, the dental system, locomotor system, and neurological system (especially the brain) all evolved at markedly different rates.

Pertaining to research involving mutual contributions and cooperation of experts from various scientific fields (i.e., disciplines).

obligate bipedalism
Bipedalism as the only form of hominin terrestrial locomotion. Major anatomical changes in the spine, pelvis, and lower limb are required for bipedal locomotion, so once hominins adapted this mode of locomotion, other forms of locomotion on the ground became impossible.

Oldowan industry
The earliest recognized stone tool culture, including very simple tools, mostly small flakes.

Pertaining to the Pliocene and first half of the Pleistocene, a time range of 5-1 mya. For this time period, numerous fossil hominins have been found in Africa.

Referring to all or part of the skeleton not including the skull. The term originates from the fact that in quadrupeds, the body is in back of the head; the term literally means “behind the head.”

sagittal crest
A ridge of bone that runs down the middle of the cranium like a short Mohawk. This serves as the attachment for the large temporal muscles, indicating strong chewing.

Locations of discoveries. In paleontology and archaeology, a site may refer to a region where a number of discoveries have been made.

Study of the sequential layering of geological deposits.

stratum (pl., strata)
Geological layer.

thermoluminescence (TL)
Technique for dating certain archaeological materials that were heated in the past (such as stone tools) and that release stored energy of radioactive decay as light upon reheating.

Acheulian (ash´-oo-lay-en)
Pertaining to a stone tool industry from the Early and Middle Pleistocene; characterized by a large proportion of bifacial tools (flaked on both sides). Acheulian tool kits are common in Africa, Southwest Asia, and western Europe, but they’re thought to be less common elsewhere. Also spelled Acheulean.

nuchal torus (nuke´-ul) (nucha, meaning “neck”)
A projection of bone in the back of the cranium where neck muscles attach. These muscles hold up the head.

The epoch of the Cenozoic from 1.8 mya until 10,000 ya. Frequently referred to as the Ice Age, this epoch is associated with continental glaciations in northern latitudes.

Pertaining to an Upper Paleolithic industry found in France and Spain, containing blade tools and associated with Neandertals.

The position of the body in a bent orientation, with arms and legs drawn up to the chest.

Climatic intervals when continental ice sheets cover much of the northern continents. Glaciations are associated with colder temperatures in northern latitudes and more arid conditions in southern latitudes, most notably in Africa.

Climatic intervals when continental ice sheets are retreating, eventually becoming much reduced in size. Interglacials in northern latitudes are associated with warmer temperatures, while in southern latitudes the climate becomes wetter.

Late Pleistocene
The portion of the Pleistocene epoch beginning 125,000 ya and ending approximately 10,000 ya.

Middle Pleistocene
The portion of the Pleistocene epoch beginning 780,000 ya and ending 125,000 ya.

Pertaining to the stone tool industry associated with Neandertals and some modern H. sapiens groups; also called Middle Paleolithic. This industry is characterized by a larger proportion of flake tools than is found in Acheulian tool kits.

Upper Paleolithic
A cultural period usually associated with modern humans, but also found with some Neandertals, and distinguished by technological innovation in various stone tool industries. Best known from western Europe, similar industries are also known from central and eastern Europe and Africa.

Pertaining to an Upper Paleolithic stone tool industry in Europe beginning at about 40,000 ya.

Small, chisel-like tools with a pointed end; thought to have been used to engrave bone, antler, ivory, or wood.

Pertaining to the final phase of the Upper Paleolithic stone tool industry in Europe.

Physiological responses to changes in the environment that occur during an individual’s lifetime. Such responses may be temporary or permanent, depending on the duration of the environmental change and when in the individual’s life it occurs. The capacity for acclimatization may typify an entire population or species, and because it’s under genetic influence, it’s subject to evolutionary factors such as natural selection and genetic drift.

biological determinism
The concept that phenomena, including various aspects of behavior (e.g., intelligence, values, morals) are governed by biological (genetic) factors; the inaccurate association of various behavioral attributes with certain biological traits, such as skin color.

breeding isolates
Populations that are clearly isolated geographically and/or socially from other breeding groups.

Continuously present in a population.

The philosophy of “race improvement” through the forced sterilization of members of some groups and increased reproduction among others; an overly simplified, often racist view that’s now discredited.

evaporative cooling
A physiological mechanism that helps prevent the body from overheating. It occurs when perspiration is produced from sweat glands and then evaporates from the surface of the skin.

gene pool
The total complement of genes shared by the reproductive members of a population.

Hardy-Weinberg equilibrium
The mathematical relationship expressing—under conditions in which no evolution is occurring—the predicted distribution of alleles in populations; the central theorem of population genetics.

A condition of balance, or stability, within a biological system, maintained by the interaction of physiological mechanisms that compensate for changes (both external and internal).

lactase persistence
In adults, the continued production of lactase, the enzyme that breaks down lactose (milk sugar). This allows adults in some human populations to digest fresh milk products. The discontinued production of lactase in adults leads to lactose intolerance and the inability to digest fresh milk.

neural tube
In early embryonic development, the anatomical structure that develops to form the brain and spinal cord.

An epidemic that spreads through many populations and may affect people worldwide. Examples include HIV/ AIDS and the “Spanish flu” pandemic of 1918-1919.

Loci with more than one allele. Polymorphisms can be expressed in the phenotype as the result of gene action (as in ABO), or they can exist solely at the DNA level within non-coding regions.

Referring to species composed of populations that differ in the expression of one or more traits.

population genetics
The study of the frequency of alleles, genotypes, and phenotypes in populations from a microevolutionary perspective.

slash-and-burn agriculture
A traditional land-clearing practice involving the cutting and burning of trees and vegetation. In many areas, fields are abandoned after a few years and clearing occurs elsewhere.

spina bifida
A condition in which the arch of one or more vertebrae fails to fuse and form a protective barrier around the spinal cord. This can lead to spinal cord damage and paralysis.

In a physiological context, any factor that acts to disrupt homeostasis; more precisely, the body’s response to any factor that threatens its ability to maintain homeostasis.

Narrowing of blood vessels to reduce blood flow to the skin. Vasoconstriction is an involuntary response to cold and reduces heat loss at the skin’s surface.

Expansion of blood vessels, permitting increased blood flow to the skin. Vasodilation permits warming of the skin and facilitates radiation of warmth as a means of cooling. Vasodilation is an involuntary response to warm temperatures, various drugs, and even emotional states (blushing).

Agents that transmit disease from one carrier to another. Mosquitoes are vectors for malaria, just as fleas are vectors for bubonic plague.

zoonotic (zoh-oh-no´-tic)
Pertaining to a zoonosis (pl., zoonoses), a disease that’s transmitted to humans through contact with nonhuman animals.

adolescent growth spurt
The period during adolescence when well-nourished teens typically increase in stature at greater rates than at other times in the life cycle.

endocrine glands
glands responsible for the secretion of hormones into the bloodstream.

Changes in phenotype that are not related to changes in underlying DNA and that may result from the interaction between the genotype and the environment.

The instructions that determine what and how genes are expressed in a cell.

essential amino acids
The 9 (of 22) amino acids that must be obtained from the food we eat because they are not synthesized in the body in sufficient amounts.

The first menstruation in girls, usually occurring in the early to midteens.

The end of menstruation in women, usually occurring around age 50.

pleiotropic genes
Genes that have more than one effect; genes that have different effects at different times in the life cycle.

Decline in physiological functioning usually associated with aging.

The most recent epoch of the Cenozoic. Following the Pleistocene, it’s estimated to have begun 10,000 years ago.

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