GENERAL HISTOLOGY

Detailed explanation-1: -The phylum Porifera comprises the sponges. Sponges are simple invertebrate animals that live in aquatic habitats. Although the majority of sponges are marine, some species live in freshwater lakes and streams.

Detailed explanation-2: -Sea sponges are one of the world’s simplest multi-cellular living organisms. Yes, sea sponges are considered animals not plants. But they grow, reproduce and survive much as plants do. They have no central nervous system, digestive system or circulatory system – and no organs!

Detailed explanation-3: -The word “Porifera” mainly refers to the pore bearers or pore bearing species. Based on the embryological studies, sponges are proved as animals and are classified into a separate Phylum in animals. This phylum includes about 5000 species. Poriferans are pore-bearing first multicellular animals.

Detailed explanation-4: -Characteristic Features of Phylum Porifera They are generally marine aquatic organisms, with a few freshwater species. Their bodies are asymmetrical. Body shape can be cylindrical, vase-like, rounded or sac-like. They are diploblastic animals with two layers, the outer dermal layer and the inner gastral layer.

Detailed explanation-5: -Sponges were traditionally distributed in three classes: calcareous sponges (Calcarea), glass sponges (Hexactinellida) and demosponges (Demospongiae).