Sycon (Scypha), Spongilla (fresh water sponge) and Euspongia (bath sponge) are all examples of animals that belong to which phylum of the animal kingdom?

Introduction / Context:
Early branching animal groups such as sponges and cnidarians are often used in exam questions to test your understanding of basic animal classification. Sycon, Spongilla, and Euspongia are classical textbook examples of sponges. Recognizing which phylum they belong to helps you quickly answer questions about simple multicellular animals.

Given Data / Assumptions:

• The organisms listed are Sycon (Scypha), Spongilla, and Euspongia.
• They are described as types of sponges, including fresh water and bath sponges.
• Options include Coelenterata, Platyhelminthes, Ctenophora, and Porifera.
• We assume standard zoological classification systems.

Concept / Approach:
Porifera is the phylum that includes all sponges. These animals have porous bodies with numerous tiny ostia through which water flows. They have a canal system, are mostly sessile, and display a cellular level of organization. Sycon, Spongilla, and Euspongia are classic examples of Porifera. Coelenterata, also called Cnidaria, includes jellyfish and corals that have a gastrovascular cavity and stinging cells. Platyhelminthes includes flatworms like planaria and tapeworms. Ctenophora includes comb jellies with eight rows of ciliary plates. None of these other phyla contain sponges.

Step-by-Step Solution:
Step 1: Recognize that Sycon, Spongilla, and Euspongia are all commonly described as sponges in zoology textbooks.Step 2: Recall that the phylum of sponges is Porifera, meaning pore bearing animals.Step 3: Examine option A, Coelenterata, which includes organisms like Hydra and jellyfish, not sponges.Step 4: Examine option B, Platyhelminthes, which includes flatworms such as planaria, not pore bearing sponges.Step 5: Examine option C, Ctenophora, which includes comb jellies with ciliary comb plates, again not sponges.Step 6: Conclude that option D, Porifera, is the correct phylum for these sponge examples.

Verification / Alternative check:
You can verify this by checking the common features of these animals. They possess porous bodies, a canal system for water flow, and are sessile. Standard classification charts place Sycon, Spongilla, and Euspongia under Porifera. Coelenterates, by contrast, have a single opening into a gastrovascular cavity and possess stinging cells, features that sponges lack. This clear difference confirms that the three examples belong to Porifera.

Why Other Options Are Wrong:
Option A is wrong because Coelenterata or Cnidaria contain jellyfish and corals, not sponges. Option B is wrong because Platyhelminthes includes dorsoventrally flattened worms. Option C is wrong because Ctenophora includes transparent marine animals with comb plates, different from sponges in both structure and function.

Common Pitfalls:
Students sometimes confuse Porifera with Coelenterata because both groups are aquatic and relatively simple. A helpful tip is to associate the word Porifera with pores and water canal systems. Once you remember that sponges have many tiny pores through which water circulates, you can easily place any sponge example such as Sycon, Spongilla, and Euspongia into Porifera, not in any other phylum. This mental link helps you avoid classification errors.

Final Answer:
Porifera, the phylum of sponges with pore bearing bodies.