This document provides an introduction to the phylum Porifera, commonly known as sponges. It discusses their key features and cellular organization, including their canal system for circulation, skeleton structure, and asexual and sexual reproduction processes. The document also lists some important sponge organisms such as the largest known sponge, a hypothetical simple sponge, and a crustacean that shows commensalism with certain sponges.

1. ANIMAL KINGDOM
PHYLUM PORIFERA

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4. Introduction, Other features, Body wall, Canal system,
Skeleton, Digestion, Respiration, Excretion, Reproduction
Synopsis

5. Introduction

6. INTRODUCTION
◈ Ellias proved that sponges are animals.
◈ Robert grant gave the name Porifera.
◈ Study of sponges is known as Parazoology.
◈ Phylogenetically evolved from choano flagillates
(Proterospongia)
◈ All are aquatic, mostly marine but few are found in fresh
water also. They are sessible, solitary or colonial.
◈ Entire body with pres i.e. numerous mouthlets Ostia and
one opening for exit Osculum.

8. Other features

9. OTHER FEATURES
◈ Sponges have various body form and shapes i.e. Gase
shape, cylindrical with radial symmetry (Leucosolenia),
irregular shape (asymmetrical).
◈ Sponges have cellular level of organisation with two
germ layer i.e. Diploblasitc and do not posses head and
appendages.

10. Body wall

11. BODY WALL
◈ Outer Dermal layer or Pinacoderm – Pinacocytes (Flat
cells), Procytes (oval)
◈ Inner Choanocytic layer or Choanoderm –
Characteristic of Porifera, Contains collar cells or
Choanocytes (flagellated)
◈ Choanocytes discovered by H.J. Clark
◈ Between these two layers gelatinous material
Mesenchyme is there. Amoebocytes are present here.

12. BODY WALL OF PORIFERA

13. AMOEBOCYTES
◈ Scleroblast - For skeleton
◈ Spongioblast - For skeleton
◈ Thesocytes - For food storage (Glycogen)
◈ Phagocytes - To engulf by phagocytosis
◈ Trophocytes - For Distribution of food
◈ Archaeocytes - Formation ova & spermatazoa (Totipotant
cells)
◈ Collencytes - Connective tissue cell
◈ Chromocytes - Pigmented Myocytes - Highly contractile (at
osculum)

14. BODY WALL OF PORIFERA

15. Canal system

16. CANAL SYSTEM
◈ Canal system of porifera helps in
◈ nutrition, respiration & excretion.
◈ Canal are developed due to folding of inner wall. There
are four types of canal systems
◈ (1) Asconoid (simplest canal) eg. Olynthus
◈ (2) Syconoid eg. Scypha
◈ (3) Leuconoid (Complex and most efficient canal system)
eg. spongilla
◈ (4) Rhagon

17. CANAL SYSTEM

18. Skeleton

19. SKELETON
◈ Skeleton is internal, consist of tiny calcarious
calcoblast or siliceous spicules sillicoblast or fine
spongin fibre spongioblast, located in mesenchyma.
◈ Scleroblast secrets spicules and Spongioblast secrets
spongin fibre.
◈ Spicule types: monoaxon, triaxon, tetraaxon, polyaxon

20. Digestion

21. DIGESTION
◈ Digestive cavity and mouth in absent. Nutrition is
holozoic.
◈ Digestion is intracellular and occurs in food vacuoles
or choanocytes. Food particle strained out by collar
cell and pass them to amoebocytes. Food is stored in
thesocytes.
◈ Distribution of food from ingestive cell to other is
brought by the movable amoeboid cell.

22. Respiration
Excretion
Nervous system

23. RESPIRATION AND EXCRETION
◈ Respiration and Excretion takes place by diffusion of
gases through body surface.
◈ Excretory matter in Ammonia.
◈ NERVOUS SYSTEM: Sponges do not have a nervous
system

24. Reproduction

25. REPRODUCTION
◈ Asexual - By Budding - Special cell mass Gemmules
containing Archaeocytes.
◈ Endogenous budding of asexual reproduction is sponge is
known as Gemmulation.
◈ Sexual - Sponges are Hermaphrodite, fertilization
internal and cross fertilization (Protogynous condition).

26. Important
organisms

27. IMPORTANT ORGANISMS
◈ Largest sponge - Spheciospongia
◈ Hypothetical simple sponge & between larva & sponge
Olynthus
◈ Scrimps - (Spongicula fish) A crustacean, shows
commensalisms with Euplecella

28. FEW SPONGES

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