HUMAN EVOLUTION GLOSSARY
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Alpha taxonomy: 1) naming and describing species. 2) Species descriptions.
Activity area: finest scale of resolution for behavior at an archeological site
Beta taxonomy: arrangement into a natural system of classification
Biface: chopper on which flaking generally covers both surfaces and the entire periphery. Bifaces do not exist in the Oldowan, and first appear about 1.7 mya ago in the Developed Oldowan or Early Acheulean.
Bifacial: flaking occurs on two intersecting surfaces. See Handaxe.
Brunhes Normal Chron: current stage of normal paleomagnetism, beginning 780 kya
C3 plants: plants that undergo photosynthetic pathway involving 3 carbon atoms. Include woody species, herbs and grasses adapted to cool growing seasons and shade. Low 13C concentration.
C4 plants: plants that undergo photosynthetic pathway involving 4 carbon atoms. Virtually all grasses adapted to hot, dry conditions and low CO2 concentrations. High 13C concentration.
Cenozoic: Era from 65 mya – present
cf (=confer): compare (Latin). denotes a case where the identity is in doubt, but the organism is similar to a known species in the opinion of whoever "cf-ed" them. Sometimes these end up being assigned to the names species, sometimes they end up being new species. Synonyms: see, see also.
chaîne opératoire: complete sequence of tool modification/reduction
Chopper: a core tool on which flaking is restricted to one edge
Conjunction (test of homology): if two supposedly homologous structures can coexist in the same organism, they are not homologous after all but two different structures.
Congruence (test of homology): pattern of association between two taxa proposed by supposed homology is supported by other homology schemes
Consistency index: a measure of how well a character fits on a tree. Computed as ci=m/s. As with the retention index, when ci=1, s=m, and there is no homoplasy – and there is a perfect fit. However, when a character fits a tree as poorly as possible, ci does not equal zero. A character that fits a tree as poorly as possible may share a ci value with a character that could have fit the tree much worse.
Core forms: pebbles and rock fragments from which flakes were removed and either 1) served only as sources of flakes or 2) were flaked to produce useful edges of desired shape
Correlation: used to determine whether two variables are
interdependent, or covary (i.e. vary together).
A common assumption is that the two are effects of a common cause.
Discoid: core tool that had been extensively flaked to resemble a disk
Disconformity:
Early Pleistocene: 1.75 - .78 mya
Exaptation:
originally selected function was other than current function (Gould and Vrba
1982)
Gamma taxonomy: analysis of intraspecific variation and the study of evolution
Gauss Chron: up to 2.6 mya, time of normal magnetism
Hammerstones: rocks that were battered and pitted by striking against other hard objects, mainly other rocks
Hand axe: (= true biface) biface with one end pointed.
Higher taxa: categories above species and genus
Holotype: type specimen
Holocene: (=Recent) epoch from 10 kya to present
Homoplasy:
Homeoplasy:
Hypodigm: fossil record for a species
Independent contrasts: makes a correction for phylogeny, to treat species as independent data points
Interdependence: degree of association between variables
Isotope: one of two or more atoms having the same atomic number (# protons) but different atomic weight and mass number.
Jaramillo Subchron: Subchron of normal polarity from .99 – 1.07 Ma (during the Matuyama Chron, which is reversed polarity)
Late Pleistocene: 125 – 10 mya
Loess-soil sequences: sequences of alternating Loess (dust) and soil. Environmental interpretations based on degree of loess and soil weathering, fossil pollen and fauna, carbonate content, and magnetism. High magnetism in fine distant dust, dominates during warm, wet periods; coarse local grains during cold, dry periods.
Lower taxa: species and genera
magn- (L: large)
Manuports: pieces of rock that were transported but not modified
Matuyama Chron: time of reversed magnetism, between Gauss Chron and Brunhes Chron, from 2.6 My to 780 kya
Middle Pleistocene: 780 - 125 kya
Milankovic climatic cycles: variations in Earth’s orbit around the sun cause fluctuations in the earth’s temperature in 100 K (eccentricity) and 41 K (obliquity) cycles.
Miocene: 23.5 – 5.2 mya, epoch between Oligocene and Pliocene
Morgan’s Canon: discounts complexity of animal behavior by mechanisms that require little intelligence, such as conditioning.
Multivariate : having or involving a number of
independent mathematical or statistical variables
Neocortex: a.k.a. isocortex; homogenetic cortex; all go through 6-layer stage in development
Neontology: the study of living species
Oxygen Isotope Stage (OIS): used in chronologies
Olduvai Subchron: Subchron of normal polarity from 1.95 mya to 1.77 mya, within reversed Matuyama Chron
Oxygen isotope ratio: measure of temperature and evaporation; d18O, the ratio of 18O (heavy) to 16O (light) is higher for colder temperatures (e.g. an ice age). We are currently in oxygen isotope stage 1.
Paleocortex: 3-layer; covers some restricted parts of the base of the telencephalon; occurs in reptiles
Paratype:
Pearson correlation coefficient, r :
Planum temporale: temporal plane; part of superior surface of the superior temporal gyrus located posterior to primary auditory cortex; usually much larger on L than on R side
Pleiotropic: producing more than one genic effect; having multiple phenotypic expressions.
Pleistocene: 1.75 - 0.01 mya, first epoch of the Quaternary Period
Pliocene: 5.2 - 1.75 mya, last epoch of the Tertiary Period
Polyhedron: core tool that had been extensively flaked to resemble a crude, multifaceted cube
Protobiface: bifacial chopper in which flaking tends to extend around the entire periphery
Purifying
selection: aka negative selection
Quaternary: Period from 1.75 mya - present
QTL (quantitative trait loci)
Radioactive isotope: (= radiotope) isotope having an unstable nucleus that decays, emitting alpha, beta or gamma rays.
Regression: a
functional relationship between two or more correlated variables that is often
empirically determined from data and is used especially to predict values of
one variable when given values of the others <the regression of y on
x is linear>; specifically : a function that yields the
mean value of a random variable under the condition that one or more
independent variables have specified values.
Regression
equation purpose is to determine dependence of variable Y on variable X, i.e.,
possible causation of changes in Y by changes in X.
Retention index: a measure of the amount of similarity in a character retained as synapomorphy on a given cladogram. Computed as r=(g-s)/(g-m), where g is the greatest number of steps that a character may require on any tree, s is the observed number of steps that a character requires for the single parsimonious tree in question, and m is the minimum number of steps that a character may exhibit on any tree. If r=1, s=m the observed number of steps required is the maximum number of steps possible, and there is no homoplasy. If r=1, s=g the observed number of steps required is the minimum number of steps possible, and there is maximum homoplasy.
Scraper: flake with intentional retouch along an edge; if small light duty, if large heavy duty
Semaphorodonts: Individuals of comparable sex and ontogenetic stage
Similarity test of homology: Detailed investigation of homologous structure including ontogeny and detailed morphology
Spheroid: core tool that had been extensively flaked to resemble a sphere
Taxonomy: 1) The system of rules for constructing a classification. 2) Classification
Turnover-pulse hypothesis:
turnover episode at 2.8-2.5 mya (originally 2.5, but expanded with
oxygen isotope data). In
Unifacial: flaking is restricted to one surface
Variability selection: certain adaptations evolve due to large environmentally caused inconsistencies in selective conditions. Selective effect is integrated over time. Complex mechanisms deal with unexpected, episodic change -- enhance ability for survival in novel conditions.