<P> Symmetry in biology is the balanced distribution of duplicate body parts or shapes within the body of an organism . In nature and biology, symmetry is always approximate . For example, plant leaves--while considered symmetrical--rarely match up exactly when folded in half . Symmetry creates a class of patterns in nature, where the near - repetition of the pattern element is by reflection or rotation . The body plans of most multicellular organisms exhibit some form of symmetry, whether radial, bilateral, or spherical . A small minority, notably among the sponges, exhibit no symmetry (i.e., are asymmetric). </P> <P> Radially symmetric organisms resemble a pie where several cutting planes produce roughly identical pieces . Such an organism exhibits no left or right sides . They have a top and a bottom surface, or a front and a back . </P> <P> Symmetry has been important historically in the taxonomy of animals; animals with radial symmetry were classified in the taxon Radiata, which is now generally accepted to be a polyphyletic assemblage of different phyla of the Animal kingdom . Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth, to the center of the opposite, aboral, end . Radial symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish . Animals in the phyla cnidaria and echinodermata are radially symmetric, although many sea anemones and some corals have bilateral symmetry defined by a single structure, the siphonoglyph . </P> <P> Many flowers are radially symmetric or actinomorphic . Roughly identical flower parts--petals, sepals, and stamens--occur at regular intervals around the axis of the flower, which is often the female part, with the carpel, style and stigma . </P>

Body parts of animal arranged around a central axis