B.P.: Before present.
backed blade: A blade (or flake) that is intentionally dulled on a
margin so it can be hand-held safely.
bacteria: Spherical,
rod-shaped, or spiral-shaped, single-cellular or multi-cellular,
filamentous prokaryotic organisms.
balanced polymorphism:
A multiplicity of forms in which the frequencies of the different
variations do not differ significantly over time because of selection
against the extremes (homozygotes).
balance model: A hypothesis
of genetic variation proposing that balancing selection maintains
large amounts of genetic variation within populations.
band: A simple form
of human social organization, consisting of one or more families.
Barr body: A highly
condensed mass of chromatin found in the nuclei of normal females,
but not in the nuclei of normal male cells. It represents a cytologically
condensed and inactivated X chromosome.
basalt: The fine-grained
member of the gabbro family of igneous rock. Its mineral composition
gives it a dark or black color.
base analog: A chemical
whose molecular structure is extremely similar to the bases normally
found in DNA.
base-pair substitution
mutation: A change in a gene such that one base pair is replaced
by another base pair; for instance, an AT is replaced by a GC pair.
basicranium: Base of
the skull, formed mainly by the occipital, petrosal (of the temporal),
and sphenoid bones.
basic research: Research
done to further knowledge for knowledge's sake.
basi-occiput: The most
anterior portion of the occipital bone on the cranial base, the
process that is in the front of the foramen magnum and meets the
sphenoid.
basion (ba): The point
where the anterior border of the foramen magnum crosses the midline.
bauplan: The basic
inter-related structural characteristics of a species.
bed: In geology, a
smal, distinct rock unit.
bending flake: A detached
piece produced by cracks initiated away from the point of applied
force. These flakes usually have a pronounced lip, contracting lateral
margins immediately below the striking platform, and no bulb of
force.
Bergmann's Rule: Warm-blooded
animals of similar shape tend to be larger in cold climates because
larger animals tend to lose heat less rapidly than the smaller ones.
Beringia: The continent,
or wide land bridge, spanning the Bering Strait between Alaska and
Siberia at times of low sea level, including contiguous parts of
both.
beveled: Usually referred
to as a tool edge that has been modified by the removal of a series
of flakes to produced a desired edge angle.
biceps brachialis muscle:
Muscle extending from below the humerus midshaft, across the front
of the elbow, and attaching on the top of the ulna. It flexes the
elbow.
biceps brachii muscle:
A two-joint muscle extending from the scapula (two attachments)
across the shoulder and elbow joints, to the radial tuberosity.
It can flex the humerus and rotate the forearm, most effectively
suppinating it.
bicondylar angle: The
angle from vertical that the shaft of the femur makes when the bone
is stood upright on its condyles.
bicuspid: A premolar
tooth.
bidirectional replication:
The DNA synthesis that takes place in both directions away from
the origin of the replication point.
biface: A tool that
has two surfaces (faces) that heet to form a single edge that circumscribes
the tool. Both faces usually contain flake scars that travel at
least half-way across the face.
bifacial thinning flake:
A flake that is removed during biface trimming and often contains
a striking platform, that is rounded or ground, indicating preparation.
It is usually thin relative to width, with a feathered termination.
bilateral kinship:
Kinship traced to relatives through both father and mother.
bilateral symmetry:
Anatomical features for which the right and left sides are close
to being mirror images of one another.
billet: A baton or
club, of material other than rock, used to detach flakes from an
objective piece by percussion. It is usually made of antler, wood,
or bone.
bilophodont: Teeth
with two crests, a type of molar construction in which there are
two parallel enamel ridges on the occlusal surface, running from
side to side connecting the cusps.
binocular vision: Overlapping
fields of vision in which both eyes can focus on a distant object
to produce a stereoscopic (three-dimensional) image.
binomial distribution:
The theoretical frequency distribution of events that have two possible
outcomes.
biochemical mutation:
See auxotrophic mutation.
biological species:
Defines a species as a reproductively isolated aggregate of populations
which can actually or potentially inetrbreed and produce fertile
offspring. The concept focuses on the importance of reproductive
isolation and the anatomical and behavioral mechanisms that create
it.
biomass: The total
weights of all living things in a particular area.
biomechanics: Pertaining
to the physics of the skeletal system, especially its static and
dynamic analyses.
biostratigraphy: Sequential
or temporal ordering of strata based on the fossils they contain.
biparental inheritance:
Plant zygotes that show traits indicating chloroplast chomosomes
from both parents are present and active.
bipedal: Two-legged.
bipolar flake: A detached
piece formed as a result of compression forces. Bipolar flakes often
show signs of impact on opposing ends and have compression rings
moving in two directions toward one another.
bipolar technique:
Removal of flakes from a core resting on a hard surface, giving
the flakes different thickness characteristics and the core a unique
form because there is a shockwave from percussion at both ends.
A technique of resting the objective piece on an anvil and striking
it with a hammer to split or remove a detached piece.
bivalent: A pair of
homologous, synapsed chromosomes during the first meiotic division.
blade tool: An artifact
formed on a parallel-sided stone flake, usually removed from a carefully
prepared core but defined as any flake whose length is more than
double its breadth.
blank: A detached piece
potentially modifiable into a specific tool form.
bonobo: A supposed
species of chimpanzee, Pan paniscus, that live in forested habitats
of Central Africa south of the Zaire River; the closest living relative
of the common chimpanzee, Pan troglodytes.
boss: A round, broad,
bulging eminence on cranial bones.
bottleneck: A form
of genetic drift that occurs when a population is drastically reduced
in size. Some genes may be lost from the gene pool as a result of
chance.
bovid: A member of
the family Bovidae, cloven-hoofed ungulates (bison, antelopes, deer,
goats, sheep, etc.). Most bones found at African sites are bovid.
bowing (limb shaft
bowing): Curvature of the long bone shaft in the anterior-posterior
plane.
Brachial Index: Ratio
of the length of the forearm divided by the length of the upper
arm (radius/humerus*100).
brachiation: Arm-over-arm
arboreal locomotion in which the animal progresses below-branches
by swinging its body between forelimn supports.
brachycephalic: Broad-headed,
having a Cephalic Index (cranial breadth/cranial length*100) over
80.
branch-point sequence:
The consenus sequence in mammalian cells, YNCURA, (where Y is a
pyrimidine, R is a purine, and N is any base) to which the free
5' end of the intron loops and binds to the A nucleotide in the
sequence during intron splicing.
breccia: Sedimentary
rock composed of angular fragments of derived material cemented
together, often the main component of cave or fissure fillings.
bregma (b): The point
at the top of the head where the coronal and sagittal sutures of
the skull meet, or where the two parietal bones meet with the frontal.
bregmatic (prebregmatic)
eminence: Small prominence on the cranial midline at or near bregma.
bridewealth: Marriage
payments from the husband and his kin to the bride's kin. Characteristically
these payments balance a transfer of rights over the wife's sexuality,
work services, residence, fertility, and so on.
broad-sense heritability:
A quantity representing the proportion of the phenotypic variance
that consists of genetic variance.
Broca's area: A cortical
region of the human brain located on the side of the frontal lobe,
just above the temporal lobe (directly beneath a finger placed at
the temple). This area is important in speech production and injury
to it will result in aphasia (language dyfunction).
browridge: A thickened
ridge or shelf of bone above the orbits at the base of the forehead,
continuously, although not necessarily evenly, developed from the
middle of the cranium to each side.
buccal: The cheek-facing
side of a postcanine tooth.
bulb of force: bun
(occipital bun): A backward extension of the cranial rear in the
form of a protuberance bounded by the nuchal plane below, a short
vertical face for the occiput behind, and a flat surface above (lambdoidal
flattening).
bunodont: Teeth with
low, rounded cusps.
burin: A chisel-like
stone tool for engraving bone, wood, horn, or soft-stone.
|
