What Type of Symmetry Do Jellyfish Have?

Symmetry is a mathematical property that makes itself evident in science and throughout nature. Symmetry is achieved when the plane of symmetry divides an object into two identical and equal parts. These parts are mirrored in each other. Symmetry is said to result in harmony in nature and among living things. It lends order to physics and to biological functions and is also used in representative modes of expression like art. Animals like jellyfish display a particular type of symmetry called radial symmetry.

  1. About Jellyfish

    • Jellyfish, members of the coelenterates group along with sea anemones and sea coral, are aquatic animals of the Cnidarian species. Jellyfish use their tentacles to catch prey and do not swim, but are carried with the ocean's current. This means most jellyfish are sessile, meaning that they do not move, and they do not require sleep or resting periods as mobile animals do. Some jellyfish use muscles to push them through the water. However, all jellyfish are radially symmetrical.

    Radial Symmetry

    • Jellyfish are radially symmetrical. Radially symmetrical animals are the second most evolved of animals. In order to be classified as radially symmetrical, the animal must have a central axis. If the animal were to be cut along that axis, more than one plane would reveal identical, or symmetrical, halves. Sessile animals, or animals that cannot move about, tend to have this type of symmetry. It allows them to reach out in many directions at once, like jellyfish do.

    Bilateral Symmetry

    • Jellyfish are not bilaterally symmetrical, meaning that they are less evolved than organisms that are. Bilateral symmetry means that an animal, if divided down the longitudinal axis of the body, or lengthwise, will reveal two identical lengthwise halves. Animals that move about constantly are most likely to be bilaterally symmetrical. Unlike jellyfish, human beings are bilaterally symmetrical.

    Animals without Symmetry

    • Animals without symmetry of any kind are called asymmetrical animals. Unlike jellyfish, they have no pattern of symmetry and are considered the simplest of all animals as far as anatomical organization is concerned. Sponges are examples of asymmetrical animals. They are considered the least evolved class of multicellular animals. Scientifically called Porifera, sponges are a step below the jellyfish's class.