Dictionary > Radial symmetry

Radial symmetry

Definition
noun
A form of symmetry in which the body plan is divisible into identical parts around a central axis
Supplement
In biology, symmetry is a characteristic of certain organisms in which there is regularity in parts on a plane or around an axis. An organism that is symmetrical (showing symmetry) would have a balanced distribution of duplicate parts on each side of the axis. It may not necessarily be an exact duplicate but an approximate repetition. An example of symmetry in organisms is bilateral symmetry.
Radial symmetry is a symmetry in which the sides exhibit correspondence or regularity of parts around a central axis. It is lacking left and right sides. It is in contrast to bilateral symmetry that is more common than radial symmetry. Most animals exhibit bilateral symmetry where there is a left and a right side along the midline. Relatively fewer animals exhibit radial symmetry. Some of them are sea stars, sea anemones, jellyfish, and sea urchins. In plant kingdom, though, there are many flowers exhibiting radial symmetry.
Special forms of radial symmetry are tetramerism (having four identical parts around a central axis) and pentamerism (with five identical parts around a central axis). Biradial symmetry is a combination of radial and bilateral symmetries, such as that of ctenophores (comb jellies).
Synonym(s):

  • radiosymmetry

Compare:

  • bilateral symmetry
  • See also:


    You will also like...

    river
    Running Water Freshwater Communities

    This tutorial introduces flowing water communities, which bring new and dithering factors into the equation for possible..

    Still Water Community Plants
    Still Water Community Plants

    This tutorial looks at the adaptations of freshwater plants for them to thrive in still water habitats. Familiarize your..

    Homeostatic Mechanisms and Cellular Communication
    Homeostatic Mechanisms and Cellular Communication

    Homeostasis is the relatively stable conditions of the internal environment that result from compensatory regulatory res..

    Control of body movement
    Control of Body Movement

    Some of the body movements can be controlled at will, others cannot. The body has a motor program, which is the pattern ..

    Direct and indirect physiologic effects of growth hormone
    Animal Growth Hormones

    Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most impor..

    Homeostasis by water regulation
    Homeostasis of Organism Water Regulation

    Osmoregulation is the regulation of water concentrations in the bloodstream, effectively controlling the amount of water..

    Related Articles...

    No related articles found

    See all Related Topics