Bilateral Symmetry

Synonyms

Plane symmetry; Reflection symmetry

Definition

Bilateral symmetry can be defined as the body plan of those animals, which can be divided into two equivalent right and left halves along the vertical plane passing through their midsagittal axis.

Introduction

Body symmetry can be defined as the morphological resemblance of parts in distinct regions and orientations of the body. Because of symmetry, the animals can be broadly divided into bilaterally symmetrical, radially symmetrical, and asymmetrical animals. Animals that can be divided into two equal right and left halves, if they are split in the perpendicular plane passing through their midsagittal body axis, e.g., flatworms, earthworms, humans, etc., are known as bilaterally symmetrical. Organisms that can be divided into two equivalent halves if they are cut through any of the radial planes are described as radially symmetrical, e.g., jellyfish, corals, and sea anemones. Animals that cannot be divided into two identical...