Skeletal components of Porifera: spicules and spongin.

Let’s go step by step to answer each part of the worksheet.

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Question 7: Describe asexual reproduction in sponges

Sponges can reproduce without needing another sponge — this is called asexual reproduction. There are three main ways they do it:

(a) Budding
A small outgrowth (like a bump) forms on the parent sponge. This bump grows into a tiny new sponge while still attached. Eventually, it breaks off and lives on its own. It’s like a baby growing right on the parent’s body until it’s ready to leave.

(b) Fragmentation & regeneration
If a piece of the sponge breaks off (maybe from waves or animals), that piece can grow into a whole new sponge! Sponges have amazing cells that can rebuild missing parts. So even a small fragment can regenerate into a full sponge if conditions are good.

(c) Gemmules
These are special “survival pods” made by some freshwater sponges when things get tough (like cold weather). Inside the gemmule are clusters of cells surrounded by a hard, protective coat. When conditions improve, these cells wake up and grow into a new sponge. Think of them like seeds for sponges!

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Question 8: What structures and materials make up the skeletons of Porifera? Describe and draw a sketch

The skeleton of sponges (Porifera) helps them keep their shape. It’s made of two main things:

- Spicules: Tiny, needle-like structures made of either calcium carbonate or silica (glass-like material). They act like internal support beams.
- Spongin: A flexible, protein-based fiber (like soft rubber bands) found in many bath sponges. It gives elasticity and holds the sponge together.

Some sponges have only spicules, some only spongin, and some have both.

*Sketch description (since we can’t draw here):*
Imagine a sponge shaped like a vase. Inside, you’d see little star-shaped or rod-shaped spicules scattered throughout. In softer sponges, you’d see a mesh of curly spongin fibers holding everything together.

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Complete the table:

We need to match cell types or structures to their descriptions.

| Type of Cell or Structure | Description |
|---------------------------|-------------|
| 9. Amoebocytes | Aid in reproduction and nutrient transport. Helps produce spicules. → These are mobile cells that carry food, help build spicules, and turn into sex cells. |
| 10. Pinacocytes | Form the outside surface of the sponge body. Contract to close porocytes. → These are flat cells covering the outer layer; they can squeeze to shut pores. |
| 11. Choanocytes | Line the interior of sponges’ body. Use flagella to draw water through pores. → Also called “collar cells,” they create water flow with their whipping tails (flagella). |
| 12. Mesohyl + Spicules/Spongin | Found as a jellylike substance between the two layers. Make up sponges’ support system. → The mesohyl is the gelatinous middle layer where spicules and spongin sit to give structure. |

*(Note: For #12, “Mesohyl” is the jellylike substance, but since it says “make up sponges’ support system,” we include what’s inside it — spicules and/or spongin — because those are the actual supportive materials.)*

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Final Answer:

7. Asexual Reproduction in Sponges:

(a) Budding: A small growth forms on the parent sponge, develops into a mini-sponge, then detaches to live independently.

(b) Fragmentation & regeneration: If a piece breaks off, it can regrow into a complete new sponge using its powerful regenerative cells.

(c) Gemmules: Hard-coated survival packages containing dormant cells; released during bad conditions and grow into new sponges when environment improves.

8. Skeleton of Porifera:

Made of spicules (tiny spikes of calcium carbonate or silica) and/or spongin (flexible protein fibers). Spicules provide rigid support; spongin provides flexibility. Some sponges use one, some both.

*(Sketch idea: Draw a simple sponge shape with dots/stars inside for spicules and wavy lines for spongin.)*

Table Completion:

9. Amoebocytes
10. Pinacocytes
11. Choanocytes
12. Mesohyl (with spicules and/or spongin)