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December 22, 2008
  1. A

    Stands for the chemical base adenine found in DNA and RNA.

    Absolute dating

    A group of methods for determining the age of objects, in years. These methods include radiometric dating, but can also involve other types as well, such as electron spin resonance and thermoluminescence.


    A stone tool industry made by Homo erectus, dating from about 1.4 million years to 200,000 years ago. Bifacial tools such as hand axes characterize it. Acheulean tools are generally found in Africa, Southwest Asia, and Europe.

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    The process by which there is some anatomical fit between an organism and its environment. Usually this is a result of natural selection.

    African apes

    The apes that live on the African continent. These include the chimpanzee, bonobo, and gorilla.


    Alternate form of a gene or trait. For example, for the gene for ABO blood type, the possible alleles are A, B, and O.


    The general term for members of the family Pongidae. They include the gorilla, chimpanzee, bonobo, and orangutan. Some include in this term members of the family Hylobatidae, which contains gibbons and siamangs; often these are referred to as the "lesser apes".


    Adapted to living in the trees.

    Archaic humans

    This is a catchall term. It stands for early Homo sapiens, as well as specimens that some researchers feel fall into separate species, such as Homo heidelbergensis, Homo antecessor, and Homo neanderthalensis.

    Ardipithecus ramidus

    The oldest known hominid; it shares many features with both apes and humans but is thought to be bipedal. It is dated to around 4.4 million years ago, and is found only in Africa.

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    An object made or modified by humans.

    Association (context)

    Objects near each other in the same geological or excavation layer. In the absence of signs of disturbance, these are often thought to be about the same age.

    Association areas (in the brain)

    Areas in the brain that contain thousands of neural connections. These areas integrate information obtained from various senses, process the information, and carry out responses. In humans, the information is also relayed to Broca's area where the information is translated for speech production.


    A tool used for throwing spears with more speed, force, and accuracy.

    Aurignacian tool tradition

    A stone tool industry made by Homo sapiens. It first appears in Europe during the Upper Paleolithic, beginning around 35,000 years ago. It is particularly noted for its high frequency of blade tools.

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    The common name for members of the hominid genus Australopithecus. All australopithecines are bipedal.

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    Australopithecus aethiopicus

    An australopithecine species with many robust features of the skull and back teeth. It is thought to be ancestral to the later robust australopithecines. It is dated to between 2.7 and 2.5 million years ago, and is found only in Africa.

    Australopithecus afarensis

    An australopithecine species that was bipedal but had many primitive features of the skeleton. Its most famous specimen is "Lucy." It is dated to between 3.9 and 3.0 million years ago, and is found only in Africa.

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    Australopithecus africanus

    An australopithecine species that was bipedal but had many primitive features of the skeleton. It is dated to between 3.0 and 2.3 million years ago, and is found only in South Africa.

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    Australopithecus anamensis

    The oldest known australopithecine. It was bipedal but had many primitive features of the skull and teeth. It is dated to between 4.2 and 3.9 million years ago, and is found only in Africa.

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    Australopithecus boisei

    An australopithecine species with many robust features of the skull and back teeth. In the group of robust australopithecines, it is dated to between 2.3 and 1.2 million years ago, and is found only in East Africa.

    Australopithecus garhi

    A newly namedaustralopithecine species that has robust teeth but is not a robust australopithecine; it is dated to 2.5 million years ago, is found only in East Africa, and may be associated with stone tools.

    Australopithecus robustus

    An australopithecine species with many robust features of the skull and back teeth. In the group of robust australopithecines, it is dated to between 2 and 1 million years ago, and is found only in South Africa.

  2. B

    A stone tool that has had flakes removed from both sides until there is an edge along the entire circumference of the tool.

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    A relative dating method that is based upon documenting evolutionary changes within a lineage of animals.


    The process of walking on two legs. This is the single most defining feature of all human ancestry.

    Body size

    In this context, this term refers primarily to stature, weight, and limb proportions.


    Pan paniscus or pygmy chimpanzee; belongs to the family Pongidae, superfamily Hominoidea.


    A short-term, drastic reduction in the population size that significantly reduces the amount of genetic variation in the population.

    Brain size

    The volume of the brain itself.

    Broca's area

    This is a part of the cerebral cortex and is related to speech. Damage to this area of the brain affects grammar and syntax.

    Brow ridge

    Large ridges of bone above the eye orbits.

    Bunning of the occipital bone

    A backward extension of the occipital bone forming a bony protuberance.


    A chisel-like tool with a pointed end. They had many uses, including carving or engraving bone, antler, and wood.

  3. C

    Stands for the chemical base cytosine found in DNA and RNA.

    Canine tooth

    The pointed tooth between the incisors and the premolars. It is used for puncturing and aggressive display.

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    The smallest structural unit of an organism that is capable of independent functioning. It consists of at least one nucleus, cytoplasm, and various organelles such as ribosomes and mitochondria, all surrounded by a semipermeable cell membrane.

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    See forebrain.

    Châtelperronian tool tradition

    A stone tool industry made by Neandertals. It first appears in Europe during the Upper Paleolithic, beginning around 35,000 years ago. It is particularly noted for its high frequency of blade tools.

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    Pan troglodytes or common chimpanzee; belongs to the family Pongidae, superfamily Hominoidea.


    Pan troglodytes or common chimpanzee; belongs to the family Pongidae, superfamily Hominoidea.


    Discrete structures of tightly coiled strands of DNA, found in the nucleus of a cell. They are only visible during certain parts of cell division.

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    The collarbone. This bone is used as a strut to strengthen the upper skeleton, particularly the arms, while hanging; it also acts as a crankshaft when raising the arm.


    The average of day-to-day weather patterns over a long period of time.


    A gradual change in the frequency of a trait over a geographic area.

    Closed communication system

    Communication system whereby a call or sound has a specific meaning; in this system new ideas cannot be expressed. Contrast with open communication system.


    Fused caudal or tail vertebrae. The coccyx is located below the sacrum.


    The quality or state of being aware of something within oneself as an individual entity or personality; the state of being that includes sensation, emotion, volition, and thought.


    The spatial and environmental surroundings of an object that is found in an archaeological setting. An object is in primary context when it has not been disturbed since deposition; it is in secondary context if something has occurred to move it, like erosion or rodent activity.


    Piece of stone from which a flake has been removed; can also be used as a tool in its own right.


    Learned and shared behavior. This includes all aspects of human behavior, including language, technology, social traditions, and social roles. It is passed on to the next generation by learning, not through DNA.


    Maintain or keep an object over time.


    The elevated bumps on the chewing surfaces of the premolars and molar teeth.

    Cytoplasm of a cell

    The portion of the cell that does not contain the nucleus. It contains a fluid and contains structures of the cell important for cell function such as the ribosome and the mitochondria.

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  4. D

    Determining the age of something. See relative dating and absolute dating.

    Decay rate

    This is the averaged constant rate at which radioactive elements change spontaneously to lower, more stable energy states.

    Deciduous forest

    Wooded environment where trees seasonally shed their leaves.


    A type of tool possibly used for woodworking. Flakes have been removed to create several curved notches along one side. This produces a serrated edge.

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    Derived feature

    A trait that is changed from the condition found in ancestors. For example, humans have a big toe in line with the other toes, a change from the ancestral condition of feet with a grasping ability.

    Developed Oldowan

    A continuation of the Oldowan tradition that includes simple pointed choppers (proto-hand axes), rough bifacial forms, and other simple flake tools. It begins around 1.5 million years ago and overlaps with later tool traditions.

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    A space or gap between two adjacent teeth. In early hominid evolution this particularly refers to the space between the lower canine and the lower first premolar.

    Diatonic scale

    Pertaining to the scale of eight tones, the eighth of which is the octave of the first. Based on or using the five tones and two semitones of the major or minor scales of Western music.


    Part of open communication system, it is the ability to communicate about objects or events that are not present, either in time or space.


    Sequences of public behavior that communicate information such as emotional state. Primate displays are most frequently associated with gaining access to reproduction, aggression, and reinforcing or changing one's place in the group dominance hierarchy.


    The double-stranded molecule that contains the genetic code. It is composed of sugars, phosphates, and the chemical bases A, C, G, and T. It provides the information to the cell for making proteins, essential for the body to develop and function.

    Dominance hierarchy

    System of social organization where individuals are ranked relative to one another. Dominant males will defend the group; dominant animals generally get more access to food and mates. Dominant females often have more surviving offspring; since they have access to better food, they can produce healthy children.

    Dominant allele

    An allele that will express itself in the organism even in the presence of another, different allele.

    Double helix

    A coiled, spiral structure that resembles a twisted rope ladder.

  5. E
    Eccentricity of Earth's orbit

    The deviation of the Earth's orbit around the sun from a nearly circular orbit. There are two cyclical changes of the Earth's orbit; a smaller one with a period of about 100,000 years, and a larger one every 400,000 years.


    The study of the relationship between organisms and all aspects of their environment.


    The total interaction of a community of organisms with their physical environment.

    Electron spin resonance

    Absolute dating method used to date crystals, such as those in tooth enamel, by measuring the density of electrons trapped in the crystal. This method is effective for dating objects from a few thousand to about 300,000 years old.

    Ellis-Van Creveld syndrome

    A form of genetic dwarfism. It is a recessive genetic condition and so can skip generations. Clinical features include disproportionately short forearms and lower limbs, a sixth finger or toe, and abnormal development of the fingernails. In the Lancaster County Amish, half the families can trace their ancestry back to one founding couple, one of whom might have carried the recessive allele.


    The hard tissue that forms the outer surface of tooth crowns.


    A solid impression (mold) of the inside of a skull. Sometimes these are naturally occurring. They are studied to identify surface details of brain structures.

    Eocene geological time period

    The Eocene epoch is part of the Tertiary Period in the Cenozoic Era, and lasted from about 54 to 38 million years ago.


    The relationship of 'If "A" goes with "B," for instance, and "B" goes with "C," does "C" go with "A"?' This important reasoning ability was thought to be a prerequisite for language ability.


    Period of sexual receptivity in many mammals, excluding modern humans. Females come into estrus when they are ovulating.


    A change in a population over time. Genetically, this means a change in the frequency of certain alleles over many generations.

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    The site of an archeological exploration. This term also refers to the process of digging a site in a systematic way according to set principles designed to preserve contextual information.

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    Experimental archaeology

    The controlled replication and use of ancient technologies in order to reconstruct and study past behaviors.


    The disappearance of a species or population in all or part of its range.

  6. F

    In science, an observation that has been repeatedly confirmed.


    Long bone of the upper leg.


    A fragment of stone removed from a core. It is usually fairly thin, with sharp edges.

    Flexed burial

    A burial where the position of the body is folded. The arms and legs of the individual are drawn towards the chest.

    Foramen magnum

    The opening at the base of the skull through which the spinal cord passes.


    Single-celled marine animals with shells. They are often used to detect climatic shifts.


    The area of the brain where most high-level brain functions take place. Its two large hemispheres make up approximately 85 percent of the brain's weight. The forebrain is thought to be the seat of language.


    Traces of living organisms preserved in rock. Fossils can be mineralized bone, plant parts or impressions.

    Founder effect

    A type of genetic drift. A small population leaves a larger population and carries with it allele frequencies which are often not representative of the total parent population. Rare alleles can be established in greater frequencies in the founding population through this event.

    Founding population

    See founder effect.

  7. G

    Stands for the chemical base guanine in DNA and RNA.

    Gallery forest

    A stretch of forest growing along a river or stream in a region otherwise devoid of trees.


    Also known as a trait, it stands for a sequence of DNA bases that provides the instructions for making a particular protein. It may be thousands of bases long.

    Gene flow

    An exchange of genes between populations through interbreeding.

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    Genetic drift

    A change of allele frequency in a population due to random events such. This force affects small populations much more than large populations.


    The branch of biology that deals with heredity, especially the mechanisms of hereditary transmission and the variation of inherited characteristics among similar or related organisms.


    To cover a landmass with ice or a glacier.


    A huge mass of ice that slowly flows over a landmass, formed from compacted snow in an area where snow accumulation exceeds melting and sublimation. Glaciers can expand and retreat depending on climatic shifts.


    The opening between the vocal cords at the upper part of the larynx.

    Gluteal muscles

    The three muscles of the buttocks: gluteus maximus, medius, and minimus. These muscles act to move the lower leg as well as stabilize the trunk during bipedal standing and walking.

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    Gorilla gorilla; belongs to the family Pongidae, superfamily Hominoidea.


    A model of macroevolutionary change that holds that evolution and speciation is slow and steady, with cumulative change occurring each generation. Contrast with punctuated equilibrium.

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    The rules in a language that oversee proper word order to provide meaning to strings of words.

    Grave goods

    Objects intentionally buried with the deceased.

    Gravettian tool tradition

    A stone tool industry made by modern humans during the Upper Paleolithic, 28,000 to 22,000 years ago. It contained bone points for tipping spears, and backed blades, among other tools. Ivory beads and Venus figurines were also common around this time.

  8. H

    The time required for half of the total atoms of a radioactive isotope to decay to a stable form.


    A stone used to strike a stone core to shape the core or remove flakes.

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    Hand axe

    A large tool that has been bifacially worked. It is normally oval or pear-shaped. It could be used as a tool itself or as a prepared core for removing more consistently shaped flakes.

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    A circle of stones that encloses a fire pit. The stones act to contain the fire and sustain its heat.


    The transmission of inherited characteristics from parent to offspring.

    Holocene geological time period

    This is the geologic epoch we are currently living in. It began around 10,000 years ago, at the end of the Pleistocene.

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    a common form of the term Hominidae. This is a taxonomic level within the hierarchy of scientific classification, and refers specifically to the Family that contains humans, chimpanzees, gorillas, and orangutans, and all their extinct relatives.

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    Common form of the term Hominini. This is a taxon ranked at the tribal level, within the hierarchy of biological classification. It refers specifically to the taxon that contains humans and their ancestors and relatives after the divergence from the common ancestor shared with Chimpanzees.

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    The common name for apes and humans, members of the superfamily Hominoidea. It consists of the families Hylobatidae gibbons and siamangs), Pongidae (gorillas, chimpanzees, bonobos, and orangutans) and Hominidae (humans).


    See hominoid.

    Homo erectus

    The first species in the genus Homo to leave Africa. There is an increase in brain size from earlier to later Homo erectus. It is dated to between 1.8 million and 300,000 years ago, and is found in Africa, Europe, and Asia.

    Homo habilis

    The first species in the genus Homo. It had some primitive features of the skeleton but shows an increase in brain size from earlier australopithecines. It is dated to between 1.9 and 1.8 million years ago, and is found only in Africa.

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    Homo neanderthalensis

    Also known as Neandertals, a population of archaic humans that lived in Europe and the Middle East. It is dated to between 150,000 and 30,000 years ago. Many believe that this group is a geographic variant of Homo sapiens, and not a separate species.

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    Homo sapiens, Early

    Early members of our species; specimens show many robust features of the skull that separate them as a group from later forms. These people lived between 600,000 and 100,000 years ago, and are found in Africa, Europe, and Asia.

    Homo sapiens, Later

    Members of our species virtually indistinguishable from living people, dating to as early as 100,000 years ago. We have a worldwide distribution, arriving in Australia around 60,000 years ago and in North and South America between 20,000 and 12,000 years ago.

    Hunters and gatherers

    Societies that employ the food-getting strategy that includes gathering plants, hunting (and often scavenging) animals, and fishing. Until about 10,000 years ago, when agriculture began to develop, all hominids were gatherers, and some were also hunters.

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    The pursuit and capture of animals for food. Hominids use tools for this purpose.

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    Small bone in the throat that supports the vocal cords and small muscles that control small movements of the jaw.


    Concept or idea that can potentially be falsified with evidence. If a statement can't be falsified by experimental results, observation, or some other means, then it is not a scientific hypothesis.

  9. I
    Ice age

    Period during which the landmasses at northern latitudes were covered in ice.

    Igneous rock

    Rock that forms from magma or lava.

    Iliac blade

    The broad, flat blade on each side of the pelvis. It provides the flare of the pelvic bone and is provides a stable attachment area for muscles.


    Carving lines, notches or symbols into a surface.

    Incisor tooth

    The broad cutting teeth at the front of the mouth, next to the canine teeth.

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    Incisor, shovel-shaped

    An incisor tooth that has ridges on each side on its inside surface, creating a scooped or shovel appearance. It is a regional genetic trait.


    A conclusion arrived at by generalizing from data or reasoning from evidence.


    Any atom that has extra neutron particles. Isotopes have the same atomic number and position in the periodic table and nearly identical chemical behavior but with different atomic mass or mass number and different physical properties.

  10. J
    No terms for this letter.


  11. K

    Family relationships. Primates recognize their kin, particularly their mother, siblings, aunts, and cousins.


    A form of quadrupedal locomotion. The knuckles of the hands support the body weight, rather than a flat palm or fingertips. African apes are knucklewalkers.

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  12. L

    Open communication system that uses a set of written, gestural, or spoken symbols that refers to people, objects or ideas.

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    The expanded upper end of the windpipe. It contains the vocal cords, regulates airflow to and from the lungs, and protects the lungs from foreign objects such as food or water.


    A descriptive generalization about how some aspect of the natural world behaves under stated circumstances.

    Law of Superposition

    A geological rule that states that objects contained in lower layers are older than those higher up in the sequence, assuming layers are relatively undisturbed. This rule is used as a relative dating technique.

    Levallois technique

    This is a method of preparing a stone core prior to removing flakes for tools. The core is first shaped a certain way in order to later produce flakes with a specific uniform shape and size. It began around 200,000 years ago.

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    A line of common descent. In a phylogeny, it is a group of ancestor-descendant species.


    Method of movement.

    Longitudinal arch of the foot

    A major specialization of the human foot. It distributes the body weight over the sole of the foot while standing, transfers weight to the big toe while walking, and acts as a shock absorber during walking and running.


    Nearly 40% complete specimen of Australopithecus afarensis; discovered by Don Johanson in 1974 and dated to around 3.18 million years old.

    Lumbar curve

    The curve of the lower back. This curve provides stability in bipedalism by keeping the center of gravity over the pelvis.

    Lumper philosophy

    The idea that species definitions should include more variation within a species; lumpers emphasize similarities between groups. Contrast with "splitter philosophy."

  13. M

    Changes produced over many generations, including the appearance of new species.

    Magdalenian tool tradition

    A stone tool industry made by modern humans at the end of the Upper Paleolithic, 18,000 to 10,000 years ago. It contained sophisticated tools such as needles, fishhooks and harpoons, weights, bows and arrows, and atlatls.

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    A human being.


    Unmodified stones moved some distance from their natural place by humans.

    Material culture

    The objects created by human activities, such as tools, art and other artifacts, shelter, clothing, and other technologies.


    A dark brown or black pigment found in skin.


    Small genetic changes that occur within populations of a species each generation.

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    The topmost structure of the brain stem containing the major relay stations for neurons transmitting signals to the cerebral cortex. It relays sensory input (visual and auditory, pain, touch, temperature) as well as motor output (movement).


    The central portion of the face containing the nose and cheeks.


    See Gene flow.


    Geologic time period ranging from 23 million to 5 million years ago. The fourth epoch of the Cenozoic era.

    Missing link

    The hypothetical intermediate form between man and his presumed monkey or ape ancestors. The concept is outdated since evolution is not modeled as a chain or ladder from primitive to modern forms, but rather as a bush with many branches, each stemming from an earlier branch.


    Structures found in the cytoplasm of the cell; they have their own DNA (mtDNA). Millions of years ago mitochondria were separate organisms that now have a symbiotic relationship with the host cell. They produce the energy for the cell, and the cell gives it safety and nutrients.

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    Mitochondrial DNA

    The DNA that codes for making mitochondria. It is inherited through the female since it is found only in the cytoplasm of the cell.

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    Molar tooth

    The large grinding teeth behind the premolars in the jaw.

    Molecular clock

    A system of dating based on the idea that many genetic differences between species are neutral mutations that are not under pressure from natural selection. The premise is that these mutations accumulate at a relatively constant rate when averaged over geologic time; the number of genetic differences between two species can then estimate the amount of time since they diverged.


    Members of the superfamily Ceboidea (New World monkeys) or Cercopithecoidea (Old World monkeys). They are long-tailed, medium-bodied, and either arboreal or terrestrial quadrupeds. New World monkeys include the capuchins, spider monkeys, howler monkeys, and marmosets. Old World monkeys include the macaques, baboons, and langur monkeys.

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    The bonding as mates of one male and one female. Some researchers think that humans are adapted to serial monogamy.

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    Smallest unit of meaning recognizable as an important language element.

    Mousterian tool tradition

    A stone tool industry made by Neandertals and early modern humans, dating from about 300,000 years to 35,000 years ago. This industry contains a wide variety of tools. They are often made with the Levallois technique, and show evidence of retouching and resharpening.

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    Multi-male, multi-female group

    A social grouping where many males and many females stay together most of the time. In most of these groups, females are related to each other, while males are not.


    The spontaneous and random occurrence of new alleles, which changes an individual's DNA. This is the raw material needed for evolution. It often occurs through copying errors.

  14. N
    Natural selection

    Changes to the frequencies of certain traits in the population. This occurs when some individuals have more surviving offspring than others due to some genetic advantage. This is sometimes referred to as "descent with modification."


    General term referring to a group of hominids living in Europe and Western Asia between 150,000 and 30,000 years ago. Researchers disagree about whether Neandertals are a separate species (Homo neanderthalensis) or the same species (Homo sapiens neanderthalensis) as modern humans.


    A type of tool possibly used for woodworking. Flakes have been removed to one curved notch along one side.

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    Nucleus of a cell

    A structure found in most cells, it contains the genetic material (DNA) for the cell.

  15. O

    Recognizing or noting a fact or occurrence often involving measurement or other objective description.


    The bone of the skull forming the back of the skull vault.


    An earthy, usually red or yellow pigment. It is made from impure iron ore.

    Oldowan tool tradition

    The oldest recognized tool tradition, dating to as early as 2.5 million years ago. Tools consist of mostly of cores, hammers, and flakes. Oldowan tools were made by Homo habilis, and perhaps also by the robust australopithecines.

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    Geologic time period ranging from 34 million to 25 million years ago. The third epoch of the Cenozoic era.

    Open communication system

    Communication system, like language, which recombines symbols to make new meanings; characterized by displacement. Contrast with closed communication system.

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    Pongo pygmaeus; belongs to the family Pongidae, superfamily Hominoidea.

  16. P

    Past environments, including climate. The study of ancient environments is called paleoecology.

    Paleolithic cultural time period

    Archaeological time period defined by cultural changes. It is separated into three categories. The Lower Paleolithic extends from 2.4 million years to 200,000 years ago, and contains the Oldowan and Acheulean tool industries. The Middle Paleolithic dates from 200,000 to 35,000 years ago, and contains the Mousterian tool industry. The Upper Paleolithic ranges from 35,000 to 10,000 years ago, and contains many industries, including the Aurignacian, Gravettian, Perigordian, Solutrean, and Magdalenian.

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    Dating method based on the movement of the Earth's magnetic pole.


    The identification of plant species through the study of preserved fossil pollen.


    Kneecap; a large bone formed within the tendon of the quadriceps femoris muscle at the knee joint.

    Pelvic inlet

    The space within the pelvic cavity that a baby passes through as it enters the bony part of the birth canal during birth.


    Also known as an awl; this tool is used to punch holes in materials such as leather and wood.

    Periglacial steppe

    An arid region near a glacial area that usually lacks many trees but contains low-water vegetation.

    Periglacial tundra

    A region near a glacial area with permanently frozen subsoil; usually lacks trees.

    Perisylvian region of the brain

    The region of the brain near the sylvan fissure, which separates the frontal, parietal, and temporal lobes. This is an important area of the brain for language ability.


    A carving or inscription on rock.


    Smallest unit of sound recognizable as an important language element. Each language will use a subset of all the possible phonemes the human throat can produce.


    A schematic representation of the history of ancestor-descendant relationships within an evolutionary lineage.


    A specimen once thought to be an early human ancestor; it had a modern human-sized brain and an apelike lower jaw. It was planted by a hoaxer and is no longer considered a fossil specimen.

    Pleistocene geological time period

    Geologic time period ranging from 1.8 million to 10,000 years ago. The sixth epoch of the Cenozoic era. During this period there were many glacial periods, which is why it is often referred to as the Ice Age.

    Pliocene geological time period

    Geologic time period ranging from 5 million to 1.8 million years ago. The fifth epoch of the Cenozoic era.


    Reproductive cells of seed-bearing plants. Each plant has a distinctive pollen shape, so pollen is useful in identifying plant species in the past.


    Having more than one mate. The bonding as mates of one male and several females (polygyny), or one female and several males (polyandry).


    Angular tools with three or more edges that intersect.


    Within a species, a group of individuals within which mates are usually chosen.


    Within a species, a group of individuals within which mates are usually chosen.

    Postorbital constriction

    A narrowing of the skull behind the eyes and before the brain vault, as viewed from above. This generally occurs in a species with larger chewing muscles.

    Potassium-argon dating

    A radiometric, absolute dating technique that is based on the decay of a radioactive isotope of potassium (40K) into stable argon gas (40Ar). It is primarily used to date volcanic rocks more than 100,000 years old.

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    Precession of Earth's equinoxes

    The wobble of the Earth's axis created by gravitational influences of other planets. This can effect climate change on Earth. The frequency of this precession is 19,000 to 23,000 years.

    Precision grip

    Grip used in holding and fine manipulation of small objects. It involves the tips of opposing thumb and fingers.


    Also known as test implications, statements that the researcher develops in order to test hypotheses. They are often written in the form of if-then statements: "if the hypothesis is true, then the following would also be true..."

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    Premolar or bicuspid tooth

    Grinding tooth located between canine and molar teeth in the jaw.

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    Members of the order Primates. It includes prosimians, monkeys, apes, and humans.

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    Primitive feature

    A trait that is found in ancestors as well as descendants. For example, in the order Primates, an ancestral feature is having five fingers, which is true of both primate ancestors and all living primates.


    An early Miocene hominoid ancestor. It is a genus that contains many fossil ape species; these creatures still retain many primitive monkey characteristics. Proconsul species lived between 23 and 17 million years ago.

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    A suborder of the order Primates; this group contains the lemurs, lorises, and tarsiers.


    The specific location where an object was found. Also spelled provenance.

    Pubic symphysis

    On the pelvis, the surface of the pubic joint in the front that attaches to the bone on the opposite side.

    Punctuated equilibrium

    A model of macroevolutionary change that holds that evolution and speciation proceed through long periods of stasis followed by periods of rapid change. Contrast with gradualism.

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  17. Q

    See quadrupedalism.


    Using all four limbs during walking.

  18. R

    A term used when attempting to biologically classify the human species into subgroups. It is a large group of populations that share certain traits in common, which makes them distinct from other groups of populations. The concept of race is very difficult to apply to patterns of human variation.
    To learn more, read the American Association of Physical Anthropologists' Statement on the Biological Aspects of Race (

    Related term:


    An object that emits radiation energy. In this context, this energy comes from the decay of unstable isotopes.

    Related term:

    Radiocarbon dating (Carbon-14 dating)

    A radiometric, absolute dating technique that is based on the decay of a radioactive isotope of carbon (14C) into stable carbon (12C). It is primarily used to date organic material younger than 50,000 years old.

    Related term:

    Radiometric dating

    A dating technique that uses the decay rate of radioactive isotopes to estimate the age of an object.

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    Rainforest environment

    A tropical woodland with an annual rainfall of at least 100 inches; characterized by tall broad-leaved trees that form a continuous canopy.

    Related term:

    Recessive allele

    An allele that will express itself in the organism only in the absence of different alleles.

    Relative dating

    A group of methods for determining whether an object is older or younger than another object. These methods include using the Law of Superposition as well as biostratigraphy.

    Remote sensing

    Nondestructive techniques that help locate sites and artifacts. These techniques include aerial photography, satellite imagery, magnetic prospecting, and side-scan and ground-penetrating radar.


    Trimming the edges of a tool in order to resharpen the edge.


    Structures found in the cytoplasm of the cell important in the manufacture of proteins.

    Related term:


    Single-stranded molecule that is important in copying DNA and in making proteins. It is composed of sugars, phosphates, and the chemical bases A, C, G, and U. Messenger RNA makes a copy of the DNA and takes the copy to the ribosome. Transfer RNA decodes the RNA sequence into an amino acid chain (protein).


    Powerfully built or large-muscled. In the case of robust australopithecines, the term robust refers to the large molars, thick jaws, and the powerful muscles needed to move them.

    Robust australopithecines

    he common name for the lineage of australopithecine that is characterized by an adaptation to eating hard, gritty foods; members include Australopithecus robustus, Australopithecus boisei, and sometimes Australopithecus aethiopicus.

  19. S

    Block of fused vertebrae that form the base of the spine and connect the two halves of the pelvis.

    Sagittal crest

    Raised ridge of bone along the midline of the skull. It forms when the chewing muscles are so large that they need additional bony areas for attachment.

    Savanna environment

    A tropical or subtropical grassland characterized by coarse grasses and scattered trees, often with seasonal rainfall.


    Eating or using the carcass of an animal that died naturally or was killed by other animals.

    Sciatic notch (greater)

    U-shaped notch at the back of the pelvis that has evolved through the rearward position of the sacrum. The sciatic nerve passes through this notch.

    Scientific method

    A research strategy, by which a person identifies a problem, creates a hypothesis, develops predictions, and tests them through the collection and analysis of data. If a hypothesis is repeatedly verified, it becomes a theory. This is known as the hypothetico-deductive model of scientific research. Scientists use this process to construct an accurate, reliable, consistent and non-arbitrary representation of the world.


    A type of tool where flakes have been removed to create a worked edge on at least one side. When the long edge is worked, the tool is classified as a side scraper, when the shorter end is worked it is called an end scraper.

    Selectively neutral

    The trait in question is not under pressure under natural selection, so the new allele is neither and advantage nor a disadvantage.

    Sexual dimorphism

    Differences in physical form between the males and females of the same species. These differences do not have to be directly related to reproduction or childbirth.

    Shared derived feature

    An unusual trait that is changed from the condition found in ancestors and is shared with another species. These features are used to define evolutionary lineages.

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    Solutrean tool tradition

    21,000 to 19,000 years ago bifacially flaked leaf-shaped knives showing precision flaking.

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    The development of new species from existing species.


    A group of organisms that only mate with each other and cannot mate and produce fertile offspring with any other group.


    A type of tool that is imperfectly round. Spheroids may not be a separate tool, but rather a hammer that has been worn down from use.

    Splitter philosophy

    The idea that species definitions should include less variation within a species; splitters emphasize differences between groups. Contrast with "lumper philosophy."


    Natural height of a person standing upright.


    An arid region that usually lacks many trees but contains low-water vegetation.


    The study of the sequential layering and deposition of sediment and sedimentary rock beds.


    In this context, an examination of the terrain of an area, looking for signs of archaeological sites.


    Something that stands for or suggests something else. In language, the sound or sign that stands for meaning.


    See grammar.

  20. T

    Stands for the chemical base thymine found in DNA.


    The study of what happens to bones and other materials between the time they are deposited and the time they are discovered. This includes the study of how objects deteriorate, carnivore and scavenger activity, erosion, weathering, and other processes.

    Termite fishing

    A technique for collecting termites. Chimpanzees in the wild place a modified stick into a termite mound, remove it, and eat any termites grasping the stick.


    Adapted to living on the ground.


    Scientific theories are explanations that are based on lines of evidence, enable valid predictions, and have been tested in many ways. In contrast, there is also a popular definition of theory — a "guess" or "hunch." These conflicting definitions often cause unnecessary confusion about evolution.


    Absolute dating technique. Heated objects (such as stone tools or rocks thrown in a campfire) when heated give off energy in the form of light and heat, and return to stable energy. By measuring the amount of energy the rock gives off when heated, researchers can estimate the amount of time that has passed since the rock was last heated.


    The larger bone in the lower leg (the smaller one is the fibula).

    Tilt of Earth's axis

    The angling of the Earth's axis away from a vertical line drawn through the plane perpendicular to the planet's orbit. This axis shifts cyclically with frequency of 41,000 years.


    The fleshy, movable, muscular organ, attached to the floor of the mouth. In speech the tongue moves to alter the sounds produced by the vocal cords.


    An object with a functional use. Tools can be manufactured, but also can be objects picked up from the natural environment and used for some purpose, such as an animal horn used as a digging stick.


    In this context, one sex usually leaves the group at sexual maturity and joins another group. This behavior avoids inbreeding.

    Transverse arch of foot

    Anatomical feature that distributes the body weight over the sole of the foot while standing and walking.

  21. U

    Stands for the chemical base uracil found in RNA.

    Usewear analysis

    One type of experimental archaeology using stone tools. A researcher uses a flake for a specific purpose (such as cutting wood), and then examines the edge damage under a microscope. Each type of activity creates a different pattern of damage on the tool edge. Some experiments have shown that a second researcher, without any prior knowledge, could successfully determine a tool's use by examining its edge. These experiments are helpful in determining the use of stone tools found archaeologically.

  22. V

    Inherited differences between individuals; the basis of all evolution.

    Vertebral spines

    A thin piece of bone that projects from a vertebra, where muscles and ligaments attach.

    Vocal cords

    Folds of mucous membrane in the throat that project into the larynx. They vibrate when pulled together, and, when air is passed up from the lungs, produce vocal sounds.

  23. W
    Wernicke's area

    A part of the cortex related to the understanding of language located in the temporal lobe.

    Woodland environment

    An environment characterized by patchy stands of relatively short trees separated by grassy areas.


    A nearly complete specimen of Homo erectus; discovered by Kamoya Kimeu in 1984 and dated to around 1.6 million years old.

  24. X
    No terms for this letter.


  25. Y
    Y-5 pattern on molar teeth

    A cusp pattern seen in the lower molars of all hominoids; there are five main cusps separated by grooves.

    Related term:

  26. Z
    No terms for this letter.