Question

Hemichordate are closely related to
A. Chordate
B. Molluscs
C. Plants
D. None of the above

Answer 1

Hemichordata (Greek, hemi-half, Chorde-cord) means they are half chordates. This phylum contains marine deuterostome animals which consists of a small group of worm-like animals. also known as stomochordata.

Complete Answer:
Let us analyse the options and find the correct answer.

Option A: The similarities between hemichordates and chordates are,
- Both have notochord.
- Presence of dorsal hollow nerve cord is seen in both.
- Presence of gill slits.

Hemichordates were initially grouped under phylum chordata, and named on the basis of a structure present in their body which was considered to be their notochord. Tus, showing a close connection with phylum Chordata. But this fact is no longer supported. And now it is placed as a separate phylum under non-chordata.Therefore, this is the correct answer.

Option B: Molluscs are soft bodied animals. The body is covered by a calcareous (Calcium carbonate) shell which is secreted by the mantle. Mantle is a characteristic feature of molluscs. There is very little to no similarity between Molluscs and Hemichordates. Therefore, this is an incorrect answer.

Option C: Plants are autographs, multicellular photosynthetic eukaryotes of the kingdom plantae. As Hemichordates belong to Kingdom Animalia, this shows that there is absolutely no connection between the both. Therefore, this is an incorrect answer.

Thus, the correct option is A) Chordate.

Note: The dissimilarities between Hemichordates and Chordates are,
- In hemichordates the dorsal hollow nerve cord is present in the collar region only.
- The notochord in Chordates is long compared to the notochord present in Hemichordates.
- The gill slits are present in lateral position in Chordates and in dorsal position in Hemichordates.