Glossary

Abduction Movement away from midline of the body or from the center of the hand or foot.

Absolute or chronometric dating In archaeology and paleoanthropology, dates for recovered material based on solar years, centuries, or other units of absolute time.

Acclimatization Long-term physiological adjustments made in order to attain an equilibrium with a specific environmental stimulus.

Acheulean tradition The tool-making tradition of Homo erectus in AfTica, Europe, and southwestern Asia in which hand-axes were developed from the earlier Oldowan chopper.

Action theory The theory that self-serving actions by forceful leaders play a role in civilization’s emergence.

Adaptation A series of beneficial adjustments to the environment. adaptive radiation Rapid diversification of an evolving population as it adapts to a variety of available niches. adduction Movement toward the midline of the body or to the center of the hand or foot.

Affiliative Tending to promote social cohesion.

Agriculture The cultivation of food plants in soil prepared and maintained for crop production. Involves using technologies other than hand tools, such as irrigation, fertilizers, and the wooden or metal plow pulled by harnessed draft animals. alleles Alternate forms of a single gene.

Allen’s rule The tendency for the bodies of mammals living in cold

Climates to have shorter appendages (arms and legs) than members of the same species living in warm climates. altruism Concern for the welfare of others expressed as increased risk undertaken by individuals for the good of the group. anagenesis A sustained directional shift in a population’s average characteristics.

Analogies In biology, structures possessed by different organisms that are superficially similar due to similar function; without sharing a common developmental pathway or structure.

Ancestral Characteristics that define a group of organisms that are due to shared ancestry.

Anthropoidea A suborder of the primates that includes New World monkeys, Old World monkeys, and apes (including humans). anthropology The study of humankind in all times and places. applied anthropology The use of anthropological knowledge and methods to solve practical problems, often for a specific client. arboreal Living in the trees.

Arboreal hypothesis A theory for primate evolution that proposes that life in the trees was responsible for enhanced visual acuity and manual dexterity in primates.

Archaeology The study of human cultures through the recovery and analysis of material remains and environmental data.

Archaic cultures Term used to refer to Mesolithic cultures in the Americas.

Archaic Homo sapiens A loosely defined group within the genus Homo that “lumpers” use for fossils with the combination of large brain size and ancestral features on the skull.

Ardipithecus ramidus One of the earliest bipeds that lived in eastern Africa about 4.4 million years ago. artifact Any object fashioned or altered by humans.

Aurignacian tradition Tool-making tradition in Europe and western Asia at the beginning of the Upper Paleolithic.

Australopithecus The genus including several species of early bipeds from East, South, and Central Africa living between about 1.1 and 4.3 million years ago, one of whom was directly ancestral to humans.

Bergmann’s rule The tendency for the bodies of mammals living in cold climates to be shorter and rounder than members of the same species living in warm climates.

Binocular vision Vision with increased depth perception from two eyes set next to each other allowing their visual fields to overlap. bioarchaeology The archaeological study of human remains emphasizing the preservation of cultural and social processes in the skeleton. biocultural Focusing on the interaction of biology and culture. bipedalism The mode of locomotion in which an organism walks upright on its two hind legs characteristic of humans and their ancestors; also called bipedality.

Blade technique A technique of stone tool manufacture by which long, parallel-sided flakes are struck off the edges of a specially prepared core.

Brachiation Using the arms to move from branch to branch, with the body hanging suspended beneath the arms.

Bronze Age In the Old World, the period marked by the production of tools and ornaments of bronze; began about 5,000 years ago in China and Southwest Asia and about 500 years earlier in Southeast Asia. burin A stone tool with chisel-like edges used for working bone and antler.

Catarrhini An anthropoid infraorder that includes Old World monkeys, apes, and humans.

Chromatid One half of the “X” shape of chromosomes visible once replication is complete. Sister chromatids are exact copies of each other. chromosomes In the cell nucleus, the structures visible during cellular division containing long strands of DNA combined with a protein. civilization In anthropology, a type of society marked by the presence of cities, social classes, and the state.

Clade A taxonomic grouping that contains a single common ancestor and all of its descendants.

Cladogenesis Speciation through a branching mechanism whereby an ancestral population gives rise to two or more descendant populations. clavicle The collarbone connecting the sternum (breastbone) with the scapula (shoulder blade).

Clines Gradual changes in the frequency of an allele or trait over space. codon Three-base sequence of a gene that specifies a particular amino acid for inclusion in a protein.

Cognitive capacity A broad concept including intelligence, educability, concept formation, self-awareness, self-evaluation, attention span, sensitivity in discrimination, and creativity. community A unit of primate social organization composed of fifty or more individuals who inhabit a large geographic area together. continental drift According to the theory of plate tectonics, the movement of continents embedded in underlying plates on the earth’s surface in relation to one another over the history of life on earth. convergent evolution In biological evolution, a process by which

Unrelated populations develop similarities to one another due to similar function rather than shared ancestry. coprolites Preserved fecal material providing evidence of the diet and health of past organisms. cranium The braincase of the skull.

Cro-Magnon A European of the Upper Paleolithic after about

36,000 years ago.

Cultural anthropology The study of customary patterns in human behavior, thought, and feelings. It focuses on humans as culture-producing and culture-reproducing creatures. Also known as social or sociocultural anthropology.

Cultural resource management A branch of archaeology tied to government policies for the protection of cultural resources and involving surveying and/or excavating archaeological and historical remains threatened by construction or development. culture A society’s shared and socially transmitted ideas, values, and perceptions, which are used to make sense of experience and generate behavior and are reflected in that behavior. culture-bound Describing theories about the world and reality based on the assumptions and values of one’s own culture.

Datum point The starting point, or reference, for a grid system. demographics Population characteristics such as the number of individuals of each age and sex.

Dendrochronology In archaeology and paleoanthropology, a technique of chronometric dating based on the number of rings of growth found in a tree trunk.

Dental formula The number of each tooth type (incisors, canines, premolars, and molars) on one half of each jaw. Unlike other mammals, primates possess equal numbers on their upper and lower jaws so the dental formula for the species is a single series of numbers. derived Characteristics that define a group of organisms and that did not exist in ancestral populations.

Developmental adaptation A permanent phenotypic variation derived from interaction between genes and the environment during the period of growth and development.

Diastema A space between the canines and other teeth allowing the large projecting canines to fit within the jaw. discourse An extended communication on a particular subject. disease Refers to a specific pathology; a physical or biological abnormality. diurnal Active during the day and at rest at night.

DNA Deoxyribonucleic acid. The genetic material consisting of a complex molecule whose base structure directs the synthesis of proteins. doctrine An assertion of opinion or belief formally handed down by an authority as true and indisputable.

Domestication An evolutionary process whereby humans modify, either intentionally or unintentionally, the genetic makeup of a population of plants or animals, sometimes to the extent that members of the population are unable to survive and/or reproduce without human assistance. dominance The ability of one allele for a trait to mask the presence of another allele.

Dominance hierarchies Observed ranking systems in primate societies ordering individuals from high (alpha) to low standing corresponding to predictable behavioral interactions including domination.

Ecofact The natural remains of plants and animals found in the archaeological record.

Ecological niche A species’ way of life considered in the full context of its environment, including factors such as diet, activity, terrain, vegetation, predators, prey, and climate.

Empirical Based on observations of the world rather than on intuition or faith.

Endemic The public health term for a disease that is widespread in a population.

Endocast A cast of the inside of a skull; used to help determine the size and shape of the brain.

Entoptic phenomena Bright pulsating forms that are generated by the central nervous system and seen in states of trance. enzyme Protein that initiates and directs chemical reactions. estrus In some primate females, the time of sexual receptivity during which ovulation is visibly displayed.

Ethnocentrism The belief that the ways of one’s own culture are the only proper ones.

Ethnography A detailed description of a particular culture primarily based on fieldwork.

Ethnology The study and analysis of different cultures from a comparative or historical point of view, utilizing ethnographic accounts and developing anthropological theories that help explain why certain important differences or similarities occur among groups.

Evolution Changes in allele frequencies in populations; also known as microevolution.

Evolutionary medicine An approach to human sickness and health combining principles of evolutionary theory and human evolutionary history.

Feature A non-portable element such as a hearth or an architectural element such as a wall that is preserved in the archaeological record. fieldwork The term anthropologists use for on-location research. flotation An archaeological technique employed to recover very tiny objects by immersion of soil samples in water to separate heavy fTom light particles.

Fluorine dating In archaeology or paleoanthropology, a technique for relative dating based on the fact that the amount of fluorine in bones is proportional to their age.

Foramen magnum A large opening in the skull through which the spinal cord passes and connects to the brain. forensic anthropology Applied subfield of physical anthropology that specializes in the identification of human skeletal remains for legal purposes.

Fossil Any mineralized trace or impression of an organism that has been preserved in the earth’s crust from past geologic time. founder effects A particular form of genetic drift deriving from a small founding population not possessing all the alleles present in the original population.

Fovea centralis A shallow pit in the retina of the eye that enables an animal to focus on an object while maintaining visual contact with its surroundings.

Gender The cultural elaborations and meanings assigned to the biological differentiation between the sexes.

Gene A portion of the DNA molecule containing a sequence of base pairs that is the fundamental physical and functional unit of heredity. gene flow The introduction of alleles from the gene pool of one population into that of another.

Gene pool All the genetic variants possessed by members of a population. genetic code The sequence of three bases (a codon) that specifies the sequence of amino acids in protein synthesis. genetic drift Chance fluctuations of allele frequencies in the gene pool of a population.

Genome The complete structure sequence of DNA for a species. genotype The alleles possessed for a particular gene. genus (genera, pl.) In the system of plant and animal classification, a group of like species.

Globalization Worldwide interconnectedness, evidenced in global movements of natural resources, trade goods, human labor, finance capital, information, and infectious diseases.

Gracile australopithecines Members of the genus Australopithecus possessing a more lightly built chewing apparatus; likely had a diet that included more meat than that of the robust australopithecines; best represented by the South African species A. africanus. grade A general level of biological organization seen among a group of species; useful for constructing evolutionary relationships. grave goods Items such as utensils, figurines, and personal possessions, symbolically placed in the grave for the deceased person’s use in the afterlife.

Grid system A system for recording data in three dimensions for an archaeological excavation.

Grooming The ritual cleaning of another animal’s coat to remove parasites and other matter.

Haplorhini In the alternate primate taxonomy, the suborder that includes tarsiers, monkeys, apes, and humans.

Hardy-Weinberg principle Demonstrates algebraically that the percentage of individuals that are homozygous for the dominant allele, homozygous for the recessive allele, and heterozygous should remain constant from one generation to the next, provided that certain specified conditions are met.

Health disparity A difference in the health status between the wealthy elite and the poor in stratified societies. hemoglobin The protein that carries oxygen in red blood cells. heterochrony Change in the timing of developmental events that is often responsible for changes in the shape or size of a body part. heterozygous Refers to a chromosome pair that bears different alleles for a single gene.

Holistic perspective A fundamental principle of anthropology: that the various parts of human culture and biology must be viewed in the broadest possible context in order to understand their interconnections and interdependence.

Home range The geographic area within which a group of primates usually moves.

Homeobox gene A gene responsible for large-scale effects on growth and development that are frequently responsible for major reorganization of body plans in organisms.

Homeotherm An animal that maintains a relatively constant body temperature despite environmental fluctuations. hominid African hominoid family that includes humans and their ancestors. Some scientists, recognizing the close relationship of humans, chimps, bonobos, and gorillas, use the term hominid to refer to all African hominoids. They then divide the hominid family into two subfamilies: the Paninae (chimps, bonobos, and gorillas) and the Homininae (humans and their ancestors). hominin The taxonomic subfamily or tribe within the primates that includes humans and our ancestors. hominoid The taxonomic division superfamily within the Old World primates that includes gibbons, siamangs, orangutans, gorillas, chimpanzees, bonobos, and humans.

Homo The genus of bipeds that appeared 2.5 million years ago characterized by increasing brain size compared to earlier bipeds. The genus is divided into various species based on features such as brain size, skull shape, and cultural capabilities.

Homo habilis “Handy man.” The first fossil members of the genus Homo appearing 2.5 million years ago, with larger brains and smaller faces than australopithecines.

Homologies In biology, structures possessed by two different organisms that arise in similar fashion and pass through similar stages during embryonic development though they may possess different functions. homozygous Refers to a chromosome pair that bears identical alleles for a single gene.

Horticulture Cultivation of crops carried out with simple hand tools such as digging sticks or hoes.

Hunting response A cyclic expansion and contraction of the blood vessels of the limbs that balances releasing enough heat to prevent frostbite with maintaining heat in the body core.

Hydraulic theory The theory that explains civilization’s emergence as the result of the construction of elaborate irrigation systems, the functioning of which required full-time managers whose control blossomed into the first governing body and elite social class. hypoglossal canal The opening in the skull that accommodates the tongue-controlling hypoglossal nerve. hypothesis A tentative explanation of the relation between certain phenomena.

Illness The meanings and elaborations given to a particular physical state. informed consent Formal recorded agreement to participate in research; federally mandated for all research in the United States and Europe.

Innovation Any new idea, method, or device that gains widespread acceptance in society.

Ischial callosities Hardened, nerveless pads on the buttocks that allow baboons and other primates to sit for long periods of time. isolating mechanism A factor that separates breeding populations, thereby preventing gene flow, creating divergent subspecies, and ultimately (if maintained) divergent species.

Isotherm An animal whose body temperature rises or falls according to the temperature of the surrounding environment.

Kenyanthropus platyops A proposed genus and species of biped contemporary with early australopithecines; may not be a separate genus. k-selected Reproduction involving the production of relatively few offspring with high parental investment in each.

Lactase An enzyme in the small intestine that enables humans to assimilate lactose.

Lactose A sugar that is the primary constituent of fresh milk. law of competitive exclusion When two closely related species compete for the same niche, one will out-compete the other, bringing about the latter’s extinction.

Law of independent assortment The Mendelian principle that genes controlling different traits are inherited independently of one another.

Law of segregation The Mendelian principle that variants of genes for a particular trait retain their separate identities through the generations. Levalloisian technique Tool-making technique by which three or four long triangular flakes were detached from a specially prepared core; developed by members of the genus Homo transitional fTom H. erectus to H. sapiens. linguistic anthropology The study of human languages—looking at their structure, history, and relation to social and cultural contexts.

Lower Paleolithic The first part of the Old Stone Age beginning with the earliest Oldowan tools spanning from about 200,000 or 250,000 to 2.6 million years ago.

Macroevolution Evolution above the species level.

Mammal The class of vertebrate animals distinguished by bodies covered with fur, self-regulating temperature, and, in females, milk-producing mammary glands.

Marrow The tissue inside of long bones where blood cells are produced. material culture The durable aspects of culture such as tools, structures, and art.

Medical anthropology A specialization in anthropology that combines theoretical and applied approaches from cultural and biological anthropology with the study of human health and disease. medical pluralism The presence of multiple medical systems, each with its own practices and beliefs in a society. medical system A patterned set of ideas and practices relating to illness. meiosis A kind of cell division that produces the sex cells, each of which has half the number of chromosomes found in other cells of the organism. melanin The chemical responsible for dark skin pigmentation that helps protect against damage from ultraviolet radiation.

Mesoamerica The region encompassing central and southern Mexico and northern Central America.

Mesolithic The Middle Stone Age period between the end of the Paleolithic and the start of the Neolithic; referred to as Archaic cultures in the Americas.

Microlith A small blade of flint or similar stone, several of which were hafted together in wooden handles to make tools; widespread in the Mesolithic.

Middens A refuse or garbage disposal area in an archaeological site. Middle Paleolithic The middle part of the Old Stone Age characterized by the development of the Mousterian tradition of tool making and the earlier Levalloisian traditions.

Mitosis A kind of cell division that produces new cells having exactly the same number of chromosome pairs, and hence copies of genes, as the parent cell.

Molecular anthropology A branch of biological anthropology that uses genetic and biochemical techniques to test hypotheses about human evolution, adaptation, and variation.

Molecular clock The hypothesis that dates of divergences among related species can be calculated through an examination of the genetic mutations that have accrued since the divergence. monogamous Mating for life with a single individual of the opposite sex. Mousterian tradition The tool industry of the Neandertals and their contemporaries of Europe, southwestern Asia, and northern Africa from

40.000  to 125,000 years ago.

Multiregional hypothesis The hypothesis that modern humans originated through a process of simultaneous local transition from Homo erectus to Homo sapiens throughout the inhabited world. mutation Chance alteration of genetic material that produces new variation.

Natal group The group or the community an animal has inhabited since birth.

Natufian culture A Mesolithic culture living in the lands that are now Israel, Lebanon, and western Syria, between about 10,200 and 12,500 years ago. natural selection The evolutionary process through which factors in the environment exert pressure, favoring some individuals over others to produce the next generation.

Neandertals A distinct group within the genus Homo inhabiting Europe and southwestern Asia from approximately 30,000 to 125,000 years ago. Neolithic The New Stone Age; prehistoric period beginning about

10.000  years ago in which peoples possessed stone-based technologies and depended on domesticated plants and/or animals.

Neolithic revolution The profound cultural change beginning about

10.000  years ago and associated with the early domestication of plants and animals and settlement in permanent villages. Sometimes referred to as the Neolithic transition.

Nocturnal Active at night and at rest during the day. notochord A rodlike structure of cartilage that, in vertebrates, is replaced by the vertebral column.

Oldowan tool tradition The first stone tool industry, beginning between 2.5 and 2.6 million years ago.

Opposable Able to bring the thumb or big toe in contact with the tips of the other digits on the same hand or foot in order to grasp objects.

Paleoanthropology The study of the origins and predecessors of the present human species; the study of human evolution.

Paleoindians The earliest inhabitants of North America. palynology In archaeology and paleoanthropology, a technique of relative dating based on changes in fossil pollen over time. participant observation In ethnography, the technique of learning a people’s culture through social participation and personal observation within the community being studied, as well as interviews and discussion with individual members of the group over an extended period of time. pastoralism Breeding and managing large herds of domesticated grazing and browsing animals, such as goats, sheep, cattle, horses, llamas, or camels.

Percussion method A technique of stone tool manufacture performed by striking the raw material with a hammerstone or by striking raw material against a stone anvil to remove flakes. phenotype The observable characteristic of an organism that may or may not reflect a particular genotype due to the variable expression of dominant and recessive alleles.

Physical anthropology The systematic study of humans as biological organisms; also known as biological anthropology. physiological adaptation A short-term physiological change in response to a specific environmental stimulus. An immediate short-term response is not very efficient and is gradually replaced by a longer term response (see acclimatization).

Platyrrhini An anthropoid infraorder that includes New World monkeys. polygenetic inheritance When two or more genes contribute to the phenotypic expression of a single characteristic. polymerase chain reaction (PCR) A technique for amplifying or creating multiple copies of fragments of DNA so that it can be studied in the laboratory.

Polymorphic Describing species with alternative forms (alleles) of particular genes.

Polytypic Describing the expression of genetic variants in different frequencies in different populations of a species. population In biology, a group of similar individuals that can and do interbreed.

Potassium-argon dating In archaeology and paleoanthropology, a technique of chronometric dating that measures the ratio of radioactive potassium to argon in volcanic debris associated with human remains. preadapted Possessing characteristics that, by chance, are advantageous in future environmental conditions. prehensile Having the ability to grasp.

Prehistory A conventional term used to refer to the period of time before the appearance of written records; does not deny the existence of history, merely of written history.

Pressure flaking A technique of stone tool manufacture in which a bone, antler, or wooden tool is used to press, rather than strike off, small flakes from a piece of flint or similar stone.

Primary innovation The creation, invention, or discovery by chance of a completely new idea, method, or device. primate The group of mammals that includes lemurs, lorises, tarsiers, monkeys, apes, and humans. primatology The study of living and fossil primates. prion An infectious protein lacking any genetic material but capable of causing the reorganization and destruction of other proteins.

Prosimii A suborder of the primates that includes lemurs, lorises, and tarsiers.

Punctuated equilibria A model of macroevolutionary change that suggests evolution occurs via long periods of stability or stasis punctuated by periods of rapid change.

Race In biology, a subspecies or a population of a species differing

Geographically, morphologically, or genetically from other populations of the same species; not applicable to people because the division of humans into discrete types does not represent the true nature of human biological variation. In some societies, race is an important social category.

Racism A doctrine of superiority by which one group justifies the dehumanization of others based on their distinctive physical characteristics. radiocarbon dating In archaeology and paleoanthropology, a technique of chronometric dating based on measuring the amount of radioactive carbon (14C ) left in organic materials found in archaeological sites. recent African origins or “Eve” hypothesis The hypothesis that all modern people are derived from one single population of archaic Homo sapiens fTom Africa who migrated out of AfTica after 100,000 years ago, replacing all other archaic forms due to their superior cultural capabilities; also called the out of Africa hypothesis. recessive An allele for a trait whose expression is masked by the presence of a dominant allele.

Relative dating In archaeology and paleoanthropology, designating an event, object, or fossil as being older or younger than another. reproductive success The relative production of fertile offspring by a genotype. In practical terms, the number of offspring produced by individual members of a population is tallied and compared to that of others.

Ribosomes Structures in the cell where translation occurs.

RNA Ribonucleic acid; similar to DNA but with uracil substituted for the base thymine. Transcribes and carries instructions from DNA from the nucleus to the ribosomes where it directs protein synthesis. Some simple life forms contain RNA only.

Robust australopithecines Several species within the genus Australopithecus, who lived from 2.5 to 1.1 million years ago in eastern and southern Africa; known for the rugged nature of their chewing apparatus (large back teeth, large chewing muscles, and a bony ridge on their skull tops for the insertion of these large muscles).

R-selected Reproduction involving the production of large numbers of offspring with relatively low parental investment in each.

Sagittal crest A crest running from front to back on the top of the skull along the midline to provide a surface of bone for the attachment of the large temporal muscles for chewing.

Sahul The greater Australian landmass including Australia, New Guinea, and Tasmania. At times of maximum glaciation and low sea levels, these areas were continuous.

Savannah Semi-arid plains environment as in eastern Africa. scapula The shoulder blade.

Secondary innovation The deliberate application or modification of an existing idea, method, or device.

Secular trend A physical difference among related people from distinct generations that allows anthropologists to make inferences about environmental effects on growth and development. seriation In archaeology and paleoanthropology, a technique for relative dating based on putting groups of objects into a sequence in relation to one another.

Sexual dimorphism Within a single species, differences in the shape or size of a feature for males and females in body features not directly related to reproduction such as body size or canine tooth shape and size. sickle-cell anemia An inherited form of anemia caused by a mutation in the hemoglobin protein that causes the red blood cells to assume a sickle shape.

Soil mark A stain that shows up on the surface of recently plowed fields that reveals an archaeological site. speciation The process of forming new species.

Species The smallest working unit in the system of classification. Among living organisms, species are populations or groups of populations capable of interbreeding and producing fertile viable offspring. stabilizing selection Natural selection acting to promote stability rather than change in a population’s gene pool. stereoscopic vision Complete three-dimensional vision (or depth

Perception) from binocular vision and nerve connections that run from each eye to both sides of the brain, allowing nerve cells to integrate the images derived from each eye.

Stratified Layered; term used to describe archaeological sites where the remains lie in layers, one upon another. stratigraphy In archaeology and paleoanthropology, the most reliable method of relative dating by means of strata.

Strepsirhini In the alternate primate taxonomy, the suborder that includes the lemurs and lorises without the tarsiers. structural violence Physical and/or psychological harm (including repression, environmental destruction, poverty, hunger, illness, and premature death) caused by exploitative and unjust social, political, and economic systems.

Sunda The combined landmass of the contemporary islands of Java, Sumatra, Borneo, and Bali that was continuous with mainland Southeast Asia at times of low sea levels corresponding to maximum glaciation.

Suspensory hanging apparatus The broad powerful shoulder joints and muscles found in all the hominoids, allowing these large-bodied primates to hang suspended below the tree branches.

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

Taxonomy The science of classification.

Tertiary scavenger In a food chain, the third animal group (second to scavenge) to obtain meat from a kill made by a predator.

Theory In science, an explanation of natural phenomena, supported by a reliable body of data.

Thrifty genotype Human genotype that permits efficient storage of fat to draw on in times of food shortage and conservation of glucose and nitrogen.

Tool An object used to facilitate some task or activity. Although tool making involves intentional modification of the material of which it is made, tool use may involve objects either modified for some particular purpose or completely unmodified.

Transcription Process of conversion of instructions from DNA into RNA.

Translation Process of conversion of RNA instructions into proteins.

Upper Paleolithic The last part (10,000 to 40,000 years ago) of the Old Stone Age, featuring tool industries characterized by long slim blades and an explosion of creative symbolic forms.

Vegeculture The cultivation of domesticated root crops, such as yams and taro.

Vertebrate An animal with a backbone, including fish, amphibians, reptiles, birds, and mammals.

Visual predation hypothesis A theory for primate evolution that proposes that hunting behavior in tree-dwelling primates was responsible for their enhanced visual acuity and manual dexterity.