bilateral symmetry


Also found in: Dictionary, Thesaurus, Encyclopedia.

symmetry

 [sim´ĕ-tre]
correspondence in size, form, and arrangement of parts on opposite sides of a plane, or around an axis. adj., adj symmet´rical.
bilateral symmetry the configuration of an irregularly shaped body (such as the human body or that of higher animals) that can be divided by a longitudinal plane into halves that are mirror images of each other.
radial symmetry that in which the body parts are arranged regularly around a central axis.

bilateral symmetry

n.
Symmetrical arrangement, as of an organism or a body part, along a central axis, so that the body is divided into equivalent right and left halves by only one plane.

bilateral symmetry

adjective Referring to a form divisible into equal mirror halves in one plane only—e.g., the right half of an organism mirrors the left.

bilateral symmetry

adjective Referring to a form divisible into equal mirror halves in one plane only

bilateral symmetry

an animal body structure in which there is a head and a rear with the body organs arranged so that a section through the midline from dorsal (upper) to ventral (lower) surfaces would divide the organism into almost identical right and left halves. Most higher invertebrates (e.g. PLATYHELMINTHS, ANNELIDS, ARTHROPODS) and all vertebrates are bilaterally symmetrical. Compare RADIAL SYMMETRY.
References in periodicals archive ?
(2-4) Studying as few as 7 paired specimens, we found that bilateral symmetry was suggested for superstructure height and footplate length and found to be statistically significant for footplate width.
Bi, "Brain image segmentation based on bilateral symmetry information," in Proceedings of the 2nd International Conference on Bioinformatics and Biomedical Engineering (iCBBE '08), pp.
In the healthy animals grown under appropriate environmental conditions, not stressed and living in a good welfare level, deviation from bilateral symmetry is expected to be small.
Departures from distinctive larval bilateral symmetry such as reductions or complete loss of arms, lobes, or ciliated bands are known in some nonfeeding larval forms of echinoderms.
Plants and organic molecules do not invest in bilateral symmetry the way animals do, but they produce many phenomena of interest because of the possibility of enantiomorphic pairs--three-dimensional shapes like the left and right hand which are mirror images of each other but which cannot be rotated to fit in the same space as each other.
These planktonic larvae look nothing like adult sea stars and have bilateral symmetry. Buffeted by currents and preyed upon by countless fish, they go through several stages of development in the first three to four weeks of their lives.
In Hegel's Aesthetics, symmetry is seen as a relatively inorganic form of nature: that of a crystal, for example (7) Higher organic forms may display bilateral symmetry, but their achievement of consciousness is reflected in the asymmetry of their viscera and other organs: "[I]n ensouled life, and higher still in the free world of the spirit, mere regularity recedes before living subjective unity." (8) The quantitative aspects of inorganic nature are subsumed into the organism and qualitatively transformed in the advance toward consciousness, on the path to that metaphysical Totality which embraces all contradictions in itself.
In his discussion of the eight key terms, Freedman notes that four of the nouns are masculine and the other four are feminine, "a clear instance of bilateral symmetry and also supporting the idea of totality and completeness, a theme deeply embedded in this poem through the use of the alphabet and the number 8" (p.
To demonstrate mirror symmetry, also known as line symmetry or bilateral symmetry, we start by creating a whimsical creature.
Subtle deviations from bilateral symmetry continue to attract a great deal of attention as possible measures of individual condition, or quality, in studies of natural and sexual selection (reviews in Moller and Pomiankowski 1993; Watson and Thornhill 1994; Markow 1995; Palmer 1996).
The limited facial asymmetry occurring on either side during normal growth and development is a part of a manifestation of mild fluctuant asymmetry, which is a random deviation from perfect bilateral symmetry in a morphological trait.
At the other extreme we have a historian like Bruno Zevi who sees fascism not only in the axes and formality of Classicism but even in something as elementary as the use of bilateral symmetry - he actually writes of symmetry being 'pathological'.

Full browser ?