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sacculated: Subdivided.
sacral vertebrae: The
fused vertebrae that make up the sacrum, at the back of the pelvis.
sacroiliac joint: The
joint at the back of the pelvis between the sacrum and the ilium.
sagittal (plane): A
vertical plane on the midline that divides the body into a right
and left half.
sagittal crest: A compound
crest of bone running along the midline of the skull for attachment
of enlarged temporalis muscles that meet along the midline.
sagittal keel (torus):
A thickening of the bone on all or part of the midline of the frontal
or parietals where they meet sagittally, or both bones.
Sahul: The name given
to the continent formed when Australia is connected to New Guinea,
during the low water level of a glaciation, also used to describe
the region.
saltation: Discontinuous
variation produced all at once by major mutation.
sample: The subset
used to give information about a population. It must be of reasonable
size and it must be a random subset of the larger group in order
to provide accurate information about the population.
sampling error: A change
in gene frequencies between parents and offspring in a population
that is due to the small size of each generation when populations
themselves are small. Small samples usually do not exactly duplicate
the characteristics of the large population they are drawn from.
sandstone: A cemented
or compacted detrital sediment composed predominantly of quartz
grains the size of sand particles.
sartorius: A muscle
extending from the anterior superior iliac spine to the medial side
of the proximal tibia, flexing the hip and knee joints.
satellite DNA: The
DNA that forms a band in an equilibrium density band that is distinct
from the band constituting the majority of the genomic DNA as a
result of a different buoyant density.
savanna: A plain characterized
by coarse grasses and scattered trees, often with seasonal rainfall.
scanning electron microscope
(SEM): An instrument for analyzing the surfaces of tiny structures
by using a focused beam of electrons to produce an enlarged image.
scapula: The flat,
triangular bone at the back of the shoulder.
scapular spine: The
projecting structure extending transversely across the back of the
scapula, holding the attachment for muscles such as the deltoid
and trapezius, and terminating in the acromion process that meets
the clavicle.
scraper: A generalized
term used to describe a flake tool that has a retouched edge angle
of approximately 60º to 90º.
seasonality: Aspects
of the environment, or of adaptations to it, that differ from one
time of year to another.
secondary nondisjunction:
A nondisjunction of the Xs in the progeny of females that were produced
by a primary nondisjunction.
secondary oocyte: A
large cell produced by the primary oocyte. In the ovaries of female
animals the diploid primary oocyte goes through meiosis I and unequal
cytokinesis to produce two cells; the large cell is called the secondary
oocyte.
secondary sexual characteristics:
Gender-related features, not directly involved in reproduction,
that develop at or after puberty.
second law: See principle
of independent assortment.
second-site mutation:
See suppressor mutation.
section system: in
alliance thoery and Australian kinship studies, division of a society
into two, four, or eight social categories through rules of descent
and allaiance. Symmetrical rules of marital allaince, enjoining
marriage with a member of one of the sections, are a normal accompaniment
of such systems.
sectorial (tooth crown):
Tooth with an elliptical or circular cross-section and a single
cusp; in anthropoids, generally referring to the lower anterior
premolar wich wears against the overlapping upper canine, creating
a honing facet on the premolar's mesial surface from cutting against
the distal edge of the canine in a scissors-like action.
sedentary: Settling
permanently in one place.
sedimentary rock: A
rock composed of the by-products of other rocks that have been eroded
or dissolved. Examples of sedimentary rocks are sandstone, mudstone,
halite, and chert.
sedimentology: A subset
of geomorphology concerned with the investigation of the structure
and texture of sediments, i.e., the global term for material deposited
on the earth's surface.
segmentary societies:
Relatively small and autonomous groups, usually of agriculturalists,
who regulate their own affairs; in some cases, they may join together
with other comparable segmentary societies to form a larger ethnic
unit.
selection: See natural
selection.
selection coefficient:
A measure of the relative intensity of selection against a genotype.
selection differential:
In natural and artificial selection, the difference between the
mean phenotype of the selected parents and the mean phenotype of
the unselected population.
selection response:
The amount that a phenotype changes in one generation when selection
is applied to a group of individuals.
self-fertilization
(selfing): The union of male and female gametes from the same individual.
self-organization:
The product of a theory derived from thermodynamics which demonstrates
that order can arise spontaneously when systems are pushed far from
an equilibrium state. The emergence of new structure arises at bifurcation
points, or thresholds of instability.
self-splicing: The
excision of introns from some precursor RNA molecules that occur
by a protein-independent reaction in some organisms.
semiconservative replicative
model: A DNA replication scheme in which each daughter molecule
retains one of the parental strands.
semidiscontinuous:
Concerning DNA replication, when one new strand is synthesized continuously
and the other discontinuously. See also discontinuous DNA replication.
semispinalis capitis:
A muscle of the nuchal region travelling down the back where it
attaches to cervical and thoracic vertebrae, important in extending
and stabilizing the head (for instance in conjunction with anterior
tooth loading).
semitendinosus: One
of the hamstring muscles, which extend the thigh and flex the leg.
sense codon: A sense
codon, as opposed to a nonsense codon, in an mRNA molecule specifies
an amino acid in the corresponding polypeptide.
sensory area: One of
the three areas of the cerebral cortex devoted to reception of information
from the body's senses.
sequence tagged site
(STS): A short segment of DNA that defines a unique position in
the human genome; an STS is usually detected by the polymerase chain
reaction.
seriation: Placement
in an order (chronological, developmental, etc.).
serrate pattern: The
combination of a very large vertically oriented mesial molar root
with a smaller distal root angled both distally and in a buccal
direction.
sesamoid: A bone formed
within a tendon.
settlement pattern:
Distribution of semi-permanent or permanent human habitations on
the landscape and within archaeological communities.
sex chromosome: A chromosome
in eukaryotic organisms that is represented differently in the two
sexes. In many organisms, one sex possesses a pair of visibly different
chromosomes. One is an X chromosome, and the other is a Y chromosome.
Commonly, the XX sex is female and the XY is male.
sex-influenced traits:
The traits that appear in both sexes but either the frequency of
occurrence in the two sexes is different or there is a different
relationship between genotype and phenotype.
sex-limited trait:
A genetically controlled character that is phenotypically exhibited
in only one of the two sexes.
sex-linked: See X-linked.
sex-linked character:
A feature whose expression is controlled by genes located on the
sex chromosomes.
sexual dimorphism:
A polymorphic character in which males and females of a species
differ in some aspect of their anatomy not directly related to reproduction
or birth.
sexual reproduction:
The reproduction involving the fusion of haploid gametes produced
by meiosis.
sexual selection: The
increased reproductive success of males or females because of characters
that enhance either their ability to compete with members of the
same sex or their attractiveness to members of the opposite sex.
shaft: The long part
of long bone, formed from the diaphyses.
shale: A sedimentary
rock formed by the cementation of very fine particles sich as mud
or silt.
shear: In chewing,
the action resulting from applied forces created when tooth surfaces
slide relative to each other, a cutting force.
shovel-shaped incisors:
Incisors that have a scooped out lingual surface because of lingual
marginal ridges, crown curvatures, or a basal tubercle alone or
in combination.
shuttle vector: A cloning
vector that can replicate in two or more host organisms. Shuttle
vectors are used for experiments in which recombinant DNA is to
be introduced into organisms other than E. coli.
sialic rocks: Refers
to igneous rocks light in color because of light minerals such as
quartz.
sigmoid notch: See
trochlear notch.
signal hypothesis:
The hypothesis that the secretion of proteins from a cell occurs
through the binding of a hydrophobic amino terminal extension to
the membrane and the subsequent removal and degradation of the extension
in the cisternal space of the endoplasmic reticulum.
signal peptidase: An
enzyme in the cisternal space of the ER that catalyzes removal of
the signal sequence from the polypeptide.
signal recognition
particle (SRP): In eukaryotes, a complex of a small RNA molecule
with six proteins, which can temporarily halt protein synthesis
by recognizing the signal sequence of a nascent polypeptide destined
to be translocated through the ER, binding to it, and hereby blocking
further translation of the mRNA.
signal sequence: The
hydrophobic, amino terminal extension found on proteins that are
secreted from a cell. The amino terminus (extension) is removed
and degraded in the cisternal space of the endoplasmic reticulum.
silencer: See silencer
element.
silencer element: In
eukaryotes, a transcriptional regulatory element that decreases
RNA transcription rather than stimulating it like other enhancer
elements.
silent mutation: A
mutational change resulting in a protein with a wild-type function
because of an unchanged amino acid sequence.
silica: A term used
to describe silicon dioxide.
silicified: Refers
to a rock hardened by silica.
siltstone: See shale.
simian: Referring to
any member of Anthropoidae (monkeys, humans, apes).
simian shelf: See mandibular
torus.
simple random sampling:
A type of probabilistic sampling where areas to be sampled are chosen
using a table of random numbers. Drawbacks include: (1) defining
the site's boudaries beforehand (2) the nature of random number
tables results in some areas being allotted clusters of sample squares,
while others remain untouched.
simple telomeric sequences:
Simple, tandemly repeated DNA sequences at, or very close to, the
extreme ends of the chromosomal DNA molecules.
SINEs (short interspersed
repeated sequences): One class of interspersed and highly repeated
sequences that consist of dispersed families with unit lengths of
fewer than 500 base pairs and repeated for as many as hundreds of
thousands of copies in the genome.
Single Species Hypothesis:
The theory that only one hominid species at a time could be expected
because culture should so broaden hominid niches that competition
for limiting resources between species would be inevitable and lead
to enhanced cultural abilities and further niche broadening. Only
one of the competing species would be expected to persist. The hypothesis
rests on the assumption that all manifestations of culture result
in effective niche expansion.
single-strand DNA binding
(SSB) proteins (helix-destabilizing proteins): Proteins that help
the DNA unwinding process by stabilizing the single-stranded DNA.
sinus: A pocket or
cavity within a cranial bone, also applied to describe the grooved
pathways for blood vessels on the endocranial surface.
sister chromatid: A
chromatid derived from replication of one chromosome during interphase
of the cell cycle.
sister exchange: Exchange
of sisters in marriage by a pair of men.
sister groups: Two
groups that result from a single split in a cladogram; they, and
only they, share the same parent taxon.
site: A distinct spatial
clusterin of artifacts, features, structures, and organic and environmental
remains, as the residue of human activity.
site catchment analysis
(SCA): A type of off-site analysis, which concentrates on the total
area from which a site's contents have been derived; at its simplest,
a site's catchment can be thought of as a full inventory of artifactual
and non-artifactual remains and their sources.
site exploitation territory
(SET): Often confused with site catchment analysis, this is a method
of achieving a fairly standardized assessment of the area habitually
used by a site's occupants.
skull: The bony skeleton
of the head, including the lower jaw.
slate: A metamorphosed
shale that breaks along flat planes.
slope (regression coefficient):
The change in one variable (y) associated with a unit increase in
another variable (x).
small nuclear ribonucleoprotein
particles (snRNPs): The complexes formed by small nuclear RNAs and
proteins in which the processing of pre-mRNA molecules occurs.
small nuclear RNA (snRNA):
Found only in eukaryotes, one of four major classes of RNA molecules
produced by transcription, snRNAs are used in the processing of
pre-mRNA molecules.
sociobiology: The study
of the biological basis of all social behavior.
soft hammer: This usually
refers to a billet but may include hammerstones of very soft materials
such as mudstone.
soft percussion (soft
hammer): An Acheulean technology that used wood, bone, or antler
instead of rock to chip flakes from a core.
somatic cell hybridization:
The fusion of two genetically different somatic cells of the same
or different species to generate a somatic hybrid for genetic analysis.
somatic mutation: A
mutation in a cell that produces a mutant spot or area, but the
mutant characteristic is not passed on to the succeeding generation.
sororate: A form of
secondary marriage whereby, upon the death of a wife, her sister
or some other close relative marries the surviving husband. This
perpetuates the marital contract between groups.
Southern blot technique:
A technique invented by E.M. Southern and used in analyzing genes
and gene transcripts, in which DNA fragments are transferred from
a gel to a nitrocellulose filter.
spacer sequences: Transcribed
sequences that are found between, and flanking, coding RNA sequences.
Spacer sequences are removed during processing or pre-rRNA and pre-tRNA
to produce mature molecules.
spatulate: Spade-like,
referring to upper incisors that are broad, often with marginal
ridges along the edges of their internal surface.
specialized: (1) Derived
or apomorphic, differing from the ancestral condition; (2) adapted
to a limited range of resources.
specialized transducing
phage: A temperate bacteriophage that can transduce only a certain
section of the bacterial chromosome.
specialized transduction:
A type of transduction in which only specific genes are transferred.
speciation: The process
whereby species multiply; the acquisition of reproductive isolation
between populations, splitting one species into two.
species: In living
animals a group of populations (Biological species) that can actually
or potentially interbreed and have fertile offspring, and are reproductively
isolated from other species. Also see Evolutionary, Genealogical,
Morpho-, and Phylogenetic species.
spermatogenesis: Development
of the male animal germ cell within the male gonad.
sperm cells (spermatozoa):
The male gametes; the spermatozoa produced by the testes in male
animals.
sphenoid bone: Irregularly
shaped bone forming part of the base and sides of the skull and
the back of the orbit.
sphere of exchange:
In non-market societies, prestige valuables and ordinary commodities
were often exchanged quite separately, i.e., valuables were exchanged
against valuables in prestige transactions, while commodities were
exchanged against commodities with much less ceremony, in mutally
profitable barter transactions. These separate systems are termed
spheres of exchange.
spine: A sharp projection
or short ridge.
spliceosomes: The splicing
complexes formed by the association of several snRNPs bound to the
pre-mRNA.
splitter: One who emphasizes
differences and formalizes variation al lower taxonomic levels (cf.
lumper).
spongy bone: See cancellous
bone.
spontaneous mutations:
The mutations that occur without the use of chemical or physical
mutagenic agents.
sporophyte: The haploid,
asexual generation in the life cycle of plants that produces haploid
spores by meiosis.
squama: The flat portion
of a cranial bone.
squamosal suture: Suture
between the parietal and temporal bones, in the form of a beveled
edge with the temporal overlapping on the outside.
stadial: A cold period
during a glaciation.
stamen: The male reproductive
organ in a flowering plant that usually consists of a stalk, called
a filament, bearing a pollen-producing anther.
standard deviation:
Approximately, the mean difference between all of the data points
in a sample and their average. Formally the square root of the variance
(V), where
V = S(|Xi - Xav|)2/(n - 1)
Xi is each data point,
Xav is the mean of the points, and n is the number of points.
standard error of gene frequency: A measure of the amount of variation
among the gene frequencies of populations. It is the square root
of the variance of gene frequency.
stasis: Little or no
evolutionary change occurring over a long period of time; see also
punctuated equilibrium.
state: A term used
to describe a social formation defined by distinct territorial boundedness,
and characterized by strong central government in which the operation
fo political power is sanctioned by legitimate force. In cultural
evolutionist models, it ranks second only to the empire as the most
complex societal development state.
stela: A free-standing
carved stone monument.
step fracture: The
scar left on the objective piece after a previous flake has been
detached with step termination.
step termination: The
distal end of a flake that terminates abruptly in a right-angle
break. This creates a "step-like" break, not to be confused
with hinge termination.
sternocleidomastoid
muscle: Extends from the mastoid process and superior nuchal line
to the sternum and the clavicle, rotating and stabilizing the head.
sternum: Breastbone.
steroid response element
(REs): The DNA sequence to which steroid hormones will bind to activate
a gene.
stochastic: Random.
stone tool: An artifact
that has been intentionally modified by retouch or unintentionally
modified by usewear. Examples of stone tools are projectile points,
unifaces, scrapers, and microliths. Debitage would not be considered
tools, but would be considered artifacts.
stop codon: See chain-terminating
codon.
stratification: The
laying down or depositing of strata or layers (also called deposits)
one above the other. A succession of layers should provide a relative
chronological sequence, with the earliest at the bottom and the
latest at the top.
stratified random sampling:
A form of probabilistic sampling in which the region or site is
divided inot natural zones or strata such as cultivated land and
forest; units are then chosen by a random number procedure so as
to give each zone a number of squares proportional to its area,
thus overcoming the inherent bias in simple random sampling.
stratified systematic
sampling: A form of probabilistic sampling which combines elements
of (1) simple random sampling (2) startified random sampling (3)
systematic sampling, in an effort to reduce sampling bias.
stratigraphy: The location
or position of fossil or other deposits relative to other buried
layers or features.
striking platform:
The surface are of an objective piece recieving the force to detach
a piece of material. This surface is often removed with the detached
piece so that the detached piece will contain the strking platform
at the point of applied force.
structural gene: A
gene that codes for an mRNA molecule and hence for a polypeptide
chain.
stylohyoid ligament:
A ligament extending from the styloid process on the cranial base
to the hyoid bone.
styloid process: A
pencil shaped, pointed process of bone that rests in the vaginal
foramen of the temporal petrous, fusing with it in older individuals.
It is the seat of attachment for the stylohyoid ligament.
sub-: Below.
subadults: An age category,
young individuals including infants, children, and juveniles.
subchron: A short period
(10 - 100 kyr) of polarity reversal within a chron.
subfossil: Recent,
often only partially fossilized, remains often from the Holocene
or historical times.
submetacentric chromosome:
A chromosome that has the centromere nearer one end than the other.
Such chromosomes appear J-shaped at anaphase.
subnasal alveolar process:
Part of the anterior maxilla below the nose, housing the roots of
the upper incisors.
subspecies: A geographically
defined aggregate of local populations which differs with various
degrees of significance (depending on the author) from other such
subdivisions of the species.
subtrochanteric: Below
(or distal to) the position of the trochanter.
sulcus: A broad groove;
on the brain's surface the sulci are the valleys between the gyri.
sum rule: The rule
that the probability of either one of two mutualy exclusive events
occurring is the sum of their individual probabilities.
Sunda: The name for
the region of mainland Southeast Asia and the western Indonesian
islands. This area is a single land mass during the low sea levl
of glaciation.
superciliary arches:
Smoothly rounded bulges of bone found on the frontal bone of the
skull at its center and extending over the inner portion of the
upper orbital border.
superior: Above.
supination: Rotation
of the forearm so that the palm faces upward; the reverse movement
from pronation.
suppressor gene: A
gene that causes suppression of mutations in other genes.
suppressor mutation:
A mutation at a second site that totally or partially restores a
function lost because of a primary mutation at another site.
supra-: Above.
suprainiac fossa: An
elliptical depression on the occiput above the superior nuchal line,
or inion.
supramastoid: The pneumatized
region on the temporal bone just above the mastoid process base.
It marks the backward extension of the root of the zygomatic process
of the temporal.
supraorbital torus:
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.
supraspecific: Above
the species level.
supratoral sulcus:
A broad depression or groove between the browridges and the frontal
bone, creating an angle between the top of the browridge and the
front of the orbital squama.
suspensory: Hanging,
locomotor and postural habits with the body below or among branches.
Sutural bone: See Wormian
bone.
suture: A joint where
two bones interdigitate and are separated by fibrous tissue. The
joints between most of the bones of the skull are sutures. Most
sutures join and the bones eventually fuse together as individuals
grow older.
Svedberg units (S values):
The conversions for sedimentation rates in sucrose density centrifugation.
Svedberg units are used as a rough indication of relative sizes
of the components being analyzed.
symmetrical alliance:
In alliance theory, a marriage system involving direct exchange.
sympatric speciation:
Speciation without geographic isolation with isolating mechanisms
developing within populations.
sympatry: The occurrance
of two or more poulations (species, etc.) in the same area.
symphyseal angle: The
angle made by the mandibular symphysis face and the lower border
of the body, such as the mandibular symphysis and pubic symphysis.
symphysis: A flexible
fibrocartilaginous joint found on the middle of the body, such as
the mandibular symphysis and the pubic symphysis.
symplesiomorphy: The
sharing of ancestral characters by several species.
synapomorphy: The sharing
of apomorphies, or derived characters, by two or more species.
synapsis: The intimate
association of homologous chromosomes brought about by the formation
of a zipperlike structure along the length of the chromatids called
the synaptonemal complex.
synaptonemal complex:
A complex structure spanning the region between meiotically paired
(synapsed) chromosomes that is concerned with crossing-over rather
than with chromosome pairing.
synchronic: Referring
to phenomena considered at a single point in time; i.e., an approach
which is not primarily concerned with change (c.f. diachronic).
synkaryon: A fusion
nucleus produced following the fusion of cells with genetically
different nuclei.
synostosis: The joining
of separate pieces of bone in human skeletons; the precise timing
of such processes is an important indicator of age.
syntax: Grammar.
syntenic: The genes
that are localized to a particular chromosome by using an experimental
approach (literally "together thread"; the term is similar
to linked).
systematics: The science
of the diversity of organisms and their relationships and classification.
systematic sampling:
A form of probabilistic sampling employing a grid of equally spaced
locations; e.g., selecting every other square. This method of regular
spcaing runs the risk of missing (or hitting) every single example
if the distribution itself is regularly spaced.
systems thinking: A
method of formal analysis in which the object of study is viewed
as comprising distinct analytical sub-units. Thus in archaeology,
it comprises a form of explanation in which a society or culture
is seen through the interaction and interdependence of its component
parts; these are referred to as system parameters, and may include
such things as population size, settlement pattern, crop production,
technology, etc.
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