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ice cores: Borings
taken from the Arctic and Antarctic polar ice caps, containing layers
of compacted ice useful for the reconstruction of paleoenvironments
and as a method of absolute dating.
igneous rock: Rock
formed as a result of the hardening of lava or magma (molten rock).
Examples of igneous rock are obsidian, basalt, and rhyolite.
iliac pillar: A bony
buttress extending vertically down the iliac blade, supporting it
against the powerful muscular forces generated by the hip abductor
muscles.
ilium (iliac blades):
The side, or broad and flat blade of the innominate, forming its
upper portion.
imaginal discs: In
the Drosophila blastoderm, undifferentiated cells that will develop
into adult tissue and organs.
immunoglobulins: Specialized
proteins (antibodies) secreted by B cells that circulate in the
blood and lymph and that are responsible for humoral immune responses.
inbreeding: Preferential
mating between close relatives.
Inca bone: A triangular
shaped Wormian bone found where the lambdoidal suture meets the
sagittal suture.
incisiform: Shaped
like an incisor.
incisive canal: Tubular
passageway between the anterior portion of the hard palate and the
floor of the nose, to carry the nerves and vessels running between
the nasal and oral cavities.
incisive foramen: Opening
of the incisive canal onto the roof of the hard palate, located
just behind (and above) the roots for the central incisors.
incisor: Broad tooth
at the front-most part of the jaw.
inclusive fitness:
A characterization of how well a feature's genetic material is represented
in the next generation because of the survival of the group of those
relatives who share it.
incomplete (partial)
dominance: The condition resulting when one allele is not completely
dominant to another allele so that the heterozygote has a phenotype
between that shown in individuals homozygous for either individual
allele involved. An example of partial dominance is the frizzle
chicken.
induced mutation: A
mutation that results from treatment with mutagens.
inducer: A chemical
or environmental agent for bacterial operons that brings about the
transcription of an operon.
induction: The synthesis
of a gene product (or products) in response to the action of an
inducer, that is, a chemical or environmental agent.
inductively coupled
plasma emission spectrometry (ICPS): Based on the same basic principles
as OES (optical emission spectrometry), but the generation of much
higher temperatures reduces problems of interference and produces
more accurate results.
industry: A group of
archaeological assemblages found over a specific region or time
whose artifacts are similar.
infanticide: The killing
of infants.
inferior: Below.
informal tools: Stone
tools made in a casual manner with only minor design constraints.
These tools are often called expediently made tools or tools made
for the need of the moment.
infraorbital foramen:
An opening under the lower orbital rim for the infraorbital nerve
and vessels.
infrared absorption
spectrometry: A technique used in the characterization of raw materials,
it has been particularly useful in distinguishing ambers from different
sources: the organic compounds in the amber absorb different wavelengths
of infrared radiation passed through them.
inion: The center of
the tuberculum linearum, a protuberance of varying expression that
develops where the superior nuchal lines meet at the sagittal plane.
It is not necessarily what is called the external occipital protuberance
(although this describes what it is) which occurs above it, at or
below where the supreme nuchal lines meet at the midline.
innerorbital: Encompassing
the orbits.
innervated: Served
by the branches of one of the nerves.
innominate (os coxae):
Large bone forming the sides of the pelvis.
insertion: The attachment
of a muscle or ligament farthest from the trunk or center of the
body.
insertion sequence
(IS) element: The simplest transposable genetic element found in
prokaryotes. It is a mobile segment of DNA that contains genes required
for the process of insertion of the DNA segment into a chromosome
and for the mobilization of the element to different locations.
inter-: Between.
interaction sphere:
A regional or interregional exchange system, e.g., the Hopewell
interaction sphere.
interaction variance
(VI): Genetic variance that arises from epistatic interactions among
genes.
intercostal muscles:
Muscles situated between the ribs.
intergenic suppressor:
A mutation whose effect is to suppress the phenotypic consequences
of another mutation in a gene distinct from the gene in which the
suppressor mutation is located.
interglacial: A warm
period between two major periods of multiple glaciations.
internal buttress (of
the mandible): Transverse torus or tori on the inside surface of
the symphysis. When the most inferior one is the most posterior
point on the internal surface, it is a simian shelf.
internal control region
(ICR): Promotor sequence, recognized by RNA polymerase III, that
is located within the gene sequence, for instance, in tRNA genes
and 5S rRNA genes of eukaryotes.
internasal angle: The
angle formed by the lengthwise joint of the two nasal bones, where
they meet at the internasal suture.
internasal suture:
The suture between the two nasal bones where they meet at the midline.
interorbital: Between
the orbits.
interpluvial: A dry
phase between two rainy periods.
interproximal facet:
Wear surface between the vertical crown walls of two adjacent teeth,
created by anterior forces and transverse motions during mastication.
interproximal wear:
Tooth wear betwean adjacent teeth, on the adjacent (mesial and distal)
sides.
interspecific allometry:
The relationship between size and shape across a range of different
species.
interstadial: A warmer
interval between stadials within a major glaciation.
interstitial wear:
See interproximal wear.
intervening sequence
(ivs): See introns.
intra- Among or within.
intragenic suppressors:
A mutation whose effect is to suppress the phenotypic consequences
of another mutation within the same gene in which the suppressor
mutation is located.
intraspecies clade:
A group of ancestral-descendant poulations that share common descent
(although not unique common descent) within a species.
intron: A nucleotide
sequence in eukaryotes that must be excised from a structural gene
transcript in order to convert the transcript into a mature messenger
RNA molecule containing only coding sequences that can be translated
into the amino acid sequence of a polypeptide.
inversion: 1) Turning
inward, for example, of the sole of the foot 2) A chromosomal mutation
that results when a segment of a chromosome is excised and then
reintegrated in an orientation 180º from the original orientation.
ischial tuberosity:
The roughened area at the base of the ischium for the hamstrings
attachment.
ischium: The lower
rear bone of the innominate.
IS element: See insertion
sequence (IS) element.
isolating mechanisms:
Biological or behavioral characteristics of individuals which prevent
sympatric groups from interbreeding.
isometry: Change in
overall size that maintains the same relative proportional shape.
isotope: Chemically
identical but anatomically different forms of an element (the number
of neutrons are different so the atomic weight differs).
isostatic uplift: Rise
in the level of the land relative to the sea caused by the relaxation
of Ice Age conditions. It occurs when the weight of ice is removed
as temperatures rise, and the landscape is raised to form raised
breaches.
isotopic analysis:
An important source of information on the reconstruction of prehistoric
diets, this technique analyses the ratios of the principle isotopes
preserved in human bone; in effect the method reads the chemical
signatures left in the body by different foods. Isotopic analysis
is also used in characterization studies.
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