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habiline: Referring
to the Homo species of Homo habilis and Homo rudolfensis.
habitat: The normal
home or environment of a group.
hackle marks: See fissures.
hafting: Attaching,
for instance when a bone or stone point is attached to a wood shaft.
half-life: The length
of time in which one-half of the nuclei of an unstable isotope of
an element decay into smaller nuclei (releasing energy).
hallux: First digit
on the foot (big toe).
hammerstone: A rock
used as a percussor to detach flakes from an objective piece. These
usually show signs of impact damage such as crushed edges.
hamstrings: A group
of muscles including biceps femoris, semimembranosus, and semitendinosus,
extending from the ischial tuberosity to the back of the femur and
top of the tibia, mainly acting to flex the hip joint.
hand axe: A teardrop
or pear shaped, bifacially flaked stone implement.
haploid: Having only
a single set of chromosomes, half the number in a normal somatic
cell. Gametes are normally haploid.
haplotype (N): Sets
of genes at more that one locus.
hard hammer: A hammerstone
made of hard rock.
Hardy-Weinberg law
(Hardy-Weinberg equilibrium, Hardy-Weinberg law of genetic equilibrium):
A extension of Mendel's laws of inheritance that describes the expected
relationship between gene frequencies in natural populations and
the frequencies of individuals of various genotypes in the same
populations.
harlequin chromosomes:
5-bromodeoxyuridine (5-BUdR), a thymidine analog, is incorporated
into DNA during replication. When both DNA strands contain 5-BUdR,
the chromatid stains less intensely than when only one DNA strand
contains the analog. When cells are grown in the presence of 5-BUdR
for two replication cycles, the two sister chromatids stained differentially
are called harlequin chromosomes.
hearth: A circle of
stones enclosing a camp fire that focuses, contains, and sustains
its heat.
helix-destabilizing
proteins: See single-strand DNA-binding (SSB) proteins.
hemisphere: One of
the two sides of the cerebrum.
hemizygous: The condition
of X-linked genes in males. Males that have an X-chromosome with
an allele for a particular gene but do not have another allele of
that gene in the gene complement are hemizygous.
herbivore (herbivorous):
Plant-eater.
hereditary traint:
A characteristic under control of the genes that is transmitted
from one generation to another.
heritability: A measure
of the extent to which a feature is inherited; that proportion of
variation of a trait in a population that is due to the variation
of genotypes.
hermaphroditic: For
animals (e.g., nematode), the species in which each individual has
both testes and ovaries; in plants, the species that have both stamens
and pistils on the same flower.
herniate: Protrude
from an abnormal opening.
Hertzian cone: The
cone formed as a result of conchoidal fracture in brittle solids.
hetero-: Different.
heterochromatin: Chromatin
that remains condensed throughout the cell cycle and is generally
inactive.
heterochrony: Evolutionary
changes caused by variation in the relative time of appearance and
rate of development of features.
heterodontic: Teeth
of the same type (for instance incisors, premolars, etc.) that differ
in size or form.
heterogametic sex:
The sex that has sex chromosomes of different types (e.g., XY) and
therefore produces two kinds of gametes with respect to the sex
chromosomes.
heterogenous nuclear
RNA (hnRNA): The RNA molecules of various sizes that exist in a
large population in the nucleus. Some of the RNA molecules are precursors
to mature mRNAs.
heterokaryon: A cell
or collection of cells (as in a mycelium) possessing genetically
different nuclei (regardless of their number) in a common cytoplasm.
heteromorphic: The
occurrence of two different alleles at a particular locus.
heteroplasmy: Extranuclear
inheritence, usually in reference to the inheritence of mtDNA from
the father.
heterosis: The phenomenon
in which the heterozygous genotypes with respect to one or more
characters are superior in comparison with the corresponding homozygous
genotypes in terms of growth, survival, phenotypic expression, and
fertility.
heterozygosity: The
proportion of individuals heterozygous at a locus; the state of
being heterozygous. See also heterozygous.
heterozygote: A form
of a polymorphism controlled by different alleles at a locus.
heterozygote advantage:
See overdominance.
heterozygous: A term
describing a diploid organism having different alleles of one or
more genes and therefore producing gametes of different genotypes.
Hfr (high-frequency
recombination): A male cell in E. coli with the F factor integrated
into the bacterial chromosome. When the F factor promotes conjunction
with a female (F-) cell, bacterial genes are transferred to the
female cell with high frequency.
higher primate: Anthropoid.
highly repetitive sequence:
A DNA sequence that is repeated between 105 and 107 times in the
genome.
hinge fracture: The
scar left by a previously removed flake detached by hinge termination.
hinge termination:
The distal end of a flake that is rounded or blunted.
histone: One of a class
of basic proteins that are complexed with DNA in chromosomes and
that play a major role in determining the structure of eukaryotic
nuclear chromosomes.
hoards: Deliberately
buried groups of valuables or prized possessions, often in times
of conflict or war, and which, for one reason or another, have not
been reclaimed.
holism: Theoretical
approach which, when applied ot human societies, sees changes as
the product of large-scale environmental, economic, and social forces
with the assumption that what individual humans wish, desire, believe,
or will is not a significant factor.
home base: A particular
place where individuals can expect to meet each other and engage
in social and other activities.
homeobox: A 180-bp
consenus sequence found in the protein-coding sequences of genes
that regulate development.
homeodomain: The 60-amino-acid
part of proteins that corresponds to the homeobox sequence of genes.
All homeodomain-containing proteins appear to be located in the
nucleus.
homeostasis: A term
used in systems thinking to describe the action of negative feedback
processes in maintaining the system at a constant equilibrium state.
homeotic mutations:
Mutations that alter the identity of particular segments, transforming
them into copies of other segments.
home range: The area
within which a group of primates usually moves over the course of
their yearly cycle.
hominid: Extant humans
and their unique ancestors and collateral relatives, extending back
in time until the split with the line leading to chimpanzees (the
closest living human relative).
hominoid: Member of
Hominoidea, the superfamily including humans and apes and their
unique ancestors.
homo-: Same.
homodontic: Teeth of
the same type with similar anatomy.
homogametic sex: The
gender in the species, most often the female, that produces only
the X sex chromosomes.
homolog: Each individual
member of a pair of homologous chromosomes.
homologous chromosomes:
The members of a chromosome pair that are identical in the arrangement
of genes they contain and in their visible structure.
homologue: A homologous
structure.
homology: A feature
in two or more species that is the same because of descent, it evolved
from the same feature in the last common ancestor of the species.
homoplasy (parallelism):
The separate appearance of a feature with the same character state
in two or more species that developed independently from a different
character state of the feature in the last common ancestor.
homozygosity: The occurence
of two identical alleles at a locus.
homozygote: A festure
controlled by a locus at which the two alleles are the same.
homozygous: A term
describing a diploid organism having the same alleles at one or
more genes and therefore producing gametes of identical genotypes.
homozygous dominant:
A diploid organism that has the same dominant allele for a given
gene locus on both members of a homologous pair of chromosomes.
homozygous recessive:
A diploid organism that has the same recessive allele for a given
gene locus on both members of a homologous pair of chromosomes.
honing facet: A worn
surface with a sharp edge on the front or back of a tooth that sildes
against a similar facet on the opposing tooth in the opposite jaw,
producing a scissors-like cutting action.
horizon: A particular
stratigraphic level or time interval, definable geologically or
by the fauna or artifacts in it.
human genome project:
A project to obtain the sequence of the complete 3 billion (3 x
109) nucleotide pairs of the human genome, and to map all of the
estimated 50,000 to 100,000 human genes.
Humerofemoral Index:
Ratio of the length of the humerus divided by the length of the
femur X 100.
humerus: Long bone
of the upper arm.
hunter-gatherers: Populations
that live by hunting (and often scavenging dead) animals, gathering
plant foods, insects and other small and relatively sedentary animals,
and sharing the fruits of these planned economic activities.
hybrid dysgenesis:
The appearance of a series of defects, including mutataions, chromosomal
aberrations, and sterility, when certain strains of Drosophila melanogaster
are crossed.
hyoid: Small U-shaped
bone of the throat supporting the vocal chords, and the site of
the muscle attachments functioning in the control of fine movements
of the lower jaw.
hypersensitive sites
(hypersensitive regions): Sites in the regions of DNA around transcriptionally
active genes that are highly sensitive to digestion by DNase I.
hypervitaminosis: A
condition resulting from a dietary excess of the vitamin concerned.
hypoplasia: Interrupted
enamel formation, leaving transverse lines, pits, or grooves visible
on the enamel surface.
hypothetico-deductive
method: Research method involving making observations, forming hypotheses
to explain the observations, making experimental predictions based
on the hypotheses, and, finally, testing the predictions. The last
step produces new observations and so a cycle is set up leading
to a refinement of the hypotheses and perhaps eventually to the
establishment of a law or an accepted principle.
hypsodont: Having teeth
with tall crowns, as in horses or Gigantopithecus.
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