Notochord in Chordata Subphyla Step by step Solution with Explanation

Your question:

In which subphylum of Chordata, notochord is present only during embryonic stage?

Notochord in Chordata Subphyla Answers and Explanation

In the phylum Chordata, the notochord is a defining feature present at some stage of development in all chordates. However, the duration and persistence of the notochord vary among the subphyla. The three main subphyla of Chordata are Urochordata (tunicates), Cephalochordata (lancelets), and Vertebrata (vertebrates). The subphylum in which the notochord is present only during the embryonic stage is Vertebrata. Here is a detailed explanation:

2. Replacement by Vertebral Column:

• As the vertebrate embryo continues to develop, the notochord is gradually replaced by the vertebral column (spine). The vertebral column is composed of a series of vertebrae, which are bony or cartilaginous structures that provide protection for the spinal cord and support for the body.

• • Protection: The vertebral column encases and protects the spinal cord, a critical component of the central nervous system.

  • Attachment Points: It provides attachment points for muscles and ligaments, facilitating movement and stability.

• In cephalochordates, the notochord is present throughout the organism’s entire life. The notochord extends from the head to the tail and provides axial support for the body.

Within the subphylum Vertebrata, the notochord is present only during the embryonic stage. It plays a crucial role in early development but is subsequently replaced by the vertebral column, which provides superior structural support and protection for the growing organism. This characteristic distinguishes vertebrates from other chordates, where the notochord may persist into adulthood or be present in a different life stage.