Question

What is radial symmetry? Give an example.

Answer 1

Hint: Symmetry is known as the parts of animals and plants are in an orderly fashion. Based on the central part, all of the body parts are divided by the size, shape and relative position. Biologically, animals have three types of symmetry. They are radial symmetry, bilateral symmetry and asymmetry. Symmetry is good for animals because if the body parts are divided equally then it can easily communicate with the environment. Its cells and shapes are conditionally connected to their activities and functions. Most importantly all the sea animals have radial symmetry. Asymmetry is found most in mammals. Humans have bilateral symmetry.
Complete answer:
In radial symmetry the parts of the objects are regularly arranged and radiated from the central point. Similar parts of the animals are arranged regularly around the central axis. Because of radial symmetry the animals easily get food from any direction. Larger, big and complex animals have this type of symmetry. Their back and front end are different. So, every part of the body is designed to do different work.
Examples of animals which have radial symmetry are jellyfish, sea urchins, corals and sea anemones. Radial symmetry provides identical body halves with respect to the central axis. Animals can’t divide based on the left and right. Here development of the head is not possible in the front side. Jellyfish don't have distinct parts. It is like a pie shaped structure. So it has radial symmetry. There are four forms of radial symmetry. They are tetramerism, pentamerism, octamerism, and hexamerism. In tetramerism the body is divided into four. In pentamerism the parts are partial equal parts around the central axis with \[72^\circ \] apart. Polyps have six fold then it is called hexamerism. Polyps have eight folds then it is called octamerism.

Note:
To get food easily and detect the threat easily for the sessile animals it has radial symmetry. The animals which have radial symmetry don’t have any head, tail, left and right side portions. So it is like a round structure. So their sense organs spread throughout the body. So it easily found their prey and threats. Radial symmetry is perfect for slow moving animals and sea side animals. Spherical symmetry and biradial symmetry are the other types of symmetry. Protozoa is the example for spherical symmetry and ctenophores are the example for biradial symmetry.