Complete A/L Biology course Part III CHP:2 Phylum Ponifera

2.0. PHYLUM PORIFERA (THE SPONGES)

2.1. GENERAL CHARACTERISTICS

1. Their body comprises of a skeleton of calcareous or silica-rich spicules or horny fibers together with many pores (holes)
2. They body has two cell layers with a single cavity
3. They are multicellular but the cells do not form tissues even though they differentiated
4. They are asymmetrical i.e. their body lacks symmetry
5. There is neither muscular or nervous system
6. They are filter-feeders. Filter feeding is a method of food obtention by some aquatic animals whereby they led water into their bodies filters out food particles from it as the water passes out
7. The adult is sessile (no locomotion is shown)
8. All are hermaphrodite and carry out asexual reproduction by budding. The have a high generative power
9. Sponges are marine and many are brightly colored

Example of a sponge is LEUCOSOLENIA

                The commercial sponges (sold int the market) for bathing are obtained by drying, beating, and thoroughly washing sponges having a skeleton of spongin made of collagen.

Chapter 3: Cnideria

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