Question

Classification of phylum Porifera is based upon

• A. Nutrition
• B. Spicules
• C. Locomotion
• D. Reproduction

Answer 1

Answer: (B)

Spicules

Porifera is the phylum composed of the sponges. Their body is composed of any minute pores. The classification of phylum Porifera is based upon the spicules. They are divided into 3 classes:

1. The class Calcarea contains the organisms in which the skeleton is made up of calcareous spicules. e.g., Leucosolenia

2. The class Hexactinellida contains the organisms in which the skeleton contains six rays of siliceous spicules. e.g., Euplectella

3. The class Demospongiae contains the organisms in which the skeleton is either absent or present. The skeleton contains spongin fibres or silicious spicules or both. e.g., Oscarella

Thus, the correct answer option B.