Question

An important characteristic that Hemichordates share with Chordates is :

• A. Ventral tubular nerve cord
• B. Pharynx with gill slits
• C. Pharynx without gill slits
• D. Absence of notochord

Answer 1

The Correct Option is B

To determine which characteristic Hemichordates share with Chordates, let's analyze the options provided:

1. Ventral tubular nerve cord: While Chordates are known for having a dorsal tubular nerve cord, Hemichordates do not share this characteristic as their nerve cord is not as developed or positioned similarly. Therefore, this is not a common characteristic between Hemichordates and Chordates.
2. Pharynx with gill slits: Both Hemichordates and Chordates have a pharynx with gill slits. This is a significant shared feature, reflecting a common evolutionary trait. Gill slits are openings in the pharynx that allow water to exit after passing over the pharyngeal respiratory surfaces, which is vital in early chordate evolution.
3. Pharynx without gill slits: This option is contrary to the characteristic shared by both groups, as both actually have pharynxes with gill slits.
4. Absence of notochord: Chordates are characterized by the presence of a notochord at some stage of their life cycle. Hemichordates, however, lack a true notochord, but this absence is not something shared with Chordates, as it contradicts a fundamental chordate feature.

After reviewing these points, the correct answer is clearly "Pharynx with gill slits." This feature highlights a shared ancestry and is key to understanding the relation between Hemichordates and Chordates.