quadruped An animal that moves using four-footed
locomotion; moves using all four limbs.
quantitative character(polygenic character; polygenic
inheritance) An inherited character or feature in a
population whose phenotypes have continuous varia-
tion, such as height or weight, and whose distribution
follows small discreet steps and can be numerically
measured or evaluated; expressed often from one
extreme to another. The effects are due to both envi-
ronment and the additive effect of two or more genes.
quantum evolution Arapid increase in the rate of
evolution over a short period of time.
quarantine Away to control or prevent importing,
exporting, or transporting of plants, animals, agricul-
tural products, and other items that may be able to
spread disease or become a pest.
quasisocial Refers to a situation where members of
the same generation share a nest and care for the
brood.
Quaternary period The most recent geologic period
ofthe Cenozoic era. It began 2 million years ago with
the growth and movement of Northern Hemisphere
continental glaciers and the Ice Age.
See alsoGEOLOGICAL TIME.quaternary structure There are four levels of struc-
turefound in polypeptides and proteins. The first or
primary structure of a polypeptide or protein deter-
mines its secondary, tertiary, and quaternary structures.
The primary structure is the amino acid sequence. This
is followed by the secondary structure, how the amino
acids adjacent to each other are organized in the struc-
ture. The tertiary or third structure is the folded three-
dimensional protein structure that allows it to perform
its role, and the fourth or quaternary structure is the
total protein structure that is made when all the sub-
units are in place. Quaternary structure is used to
describe proteins composed of multiple subunits or mul-
tiple polypeptide molecules, each called a monomer. The
arrangement of the monomers in the three-dimensional
protein is the quaternary structure. A considerable
range of quaternary structure is found in proteins.queen A member of the reproductive caste in semiso-
cial or eusocial insect species.queenright A colony that contains a functional
queen. A monogynous colony in which one morpho-
logically different female ant is the only reproducer.281