Bilateral symmetry is a concept in biology where an organism can be divided into two identical halves. When it comes to spelling this term, the stress falls on the second syllable: /baɪˈlætərəl/ sym·me·try. The first syllable "bi-" means "two," and "lateral" means "related to the side." Thus, bilateral symmetry refers to an organism having two sides that are mirror images of each other. This phenomenon is observed in many animal species, including humans, and is considered to be an important trait in evolutionary biology.
Bilateral symmetry refers to the arrangement of body parts or features in a symmetrical manner along a central axis, resulting in two mirrored halves. It is a characteristic commonly observed in many living organisms, including animals and plants.
In animals, bilateral symmetry typically means that the body can be divided into two equal halves, where each side is nearly a mirror image of the other. This trait can be seen in various anatomical features such as limbs, eyes, ears, and other sensory organs. The central axis, known as the sagittal plane, runs vertically through the body, separating the left and right sides.
Bilateral symmetry provides several advantages to organisms. It facilitates coordinated movement, improves balance, and enhances sensory perception. Additionally, it allows for specialization and differentiation of body parts. This symmetry is particularly evident in animals that actively move and explore their surroundings, as it enables them to navigate and respond to stimuli efficiently.
In plants, bilateral symmetry can be observed in the arrangement of flowers, leaves, and other reproductive structures. Similar to animals, this symmetry aids in attracting pollinators and optimizing exposure to sunlight.
Overall, bilateral symmetry plays a crucial role in the organization and functionality of organisms. It provides a foundation for various physiological and anatomical adaptations, enabling the efficient operation and survival of many species.
That construction in vertebrate animals where the organs of the body are arranged more or less distinctly in pairs.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.
The word "bilateral" originated from the Latin word "bi-" meaning "two" and "late" meaning "side". The term "symmetry" comes from the Greek word "symmetria" meaning "agreement in dimensions, due proportion, arrangement". Therefore, when combined, "bilateral symmetry" refers to the characteristic of having two symmetrical sides or halves that mirror each other.