Sponges are the most primitive multicellular animals, belonging to phylum Porifera. There are over 7,000 sponge species, most of which are marine. Sponges are sessile filter feeders that live in shallow waters and vary in size and shape. They lack tissues and organs. The three classes of sponges are Calcarea, Demospongiae, and Hexactinellida, which differ in the material that makes up their skeleton structures called spicules. Sponges reproduce both sexually and asexually.

1. Phylum Porifera
The Sponges
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Phylum Porifera

2. Phylum Porifera Overview
 Most
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
There is some debate if sponges are complex
colonial protozans and not metazoans.
Sponges
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primitive of the multicellular animals
Over 7,000 species, approximately 40 species that occur in
local waters
2% of all sponges are freshwater, none are terrestrial
Phylum Porifera

3. Phylum Porifera Overview
 Sponges
occur in shallow water habitats and
vary widely in size (up to 1m. high) and shape
– Unlike most metazoans they lack:
 All
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sponges are sessile filter feeders
Phylum Porifera

4. Sponge Diversity
Erect Rope
Sponge
Black-ball sponge
Yellow Tube
Sponge
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Phylum Porifera

5. Porifera Anatomy
 Spongocoel
 Ostia
 Oscules
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Phylum Porifera

6. Collar Cells
 Choanocytes:
Choanocytes
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(collar cells) act
as a pump to bring water into
the sponge
Phylum Porifera

7. Sponge Support
 Collagen
is found
between the inner canals
and chambers
–
Mesohyl
 Ameboid
cells located in
the mesohyl, have
different roles
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Archeocytes
Sclerocytes
Phylum Porifera

8. Sponge Support
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Phylum Porifera

9. Spicules
 Collagen
is stiffened
by adding microscopic
mineral accretions or
additional protein
fibers (spongin) or
both.
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Spicules: skeleton
structures, made of
calcium carbonate
(CaCO3) or silicon
dioxide (SiO2).
Spicules
Phylum Porifera

10. Sponge Types

11. Porifera Reproduction
 Asexual
budding
 Regeneration: can regenerate from broken
pieces
 Sexual
–
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Usually hermaphroditic with male and female cells
scattered throughout the connective tissue.
Phylum Porifera

12. Porifera Larvae
 Neighboring
sponges
are fertilized by
sperm entering
through the ostia
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Ciliated mouth less
larvae
(parenchymella) is
released.
Parenchymella
Phylum Porifera

14. Porifera Classification
 Phylum
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Porifera
Class Calcarea
Class Demospongiae
Class Hexactinellida
Sclerospongiae is no
longer considered a
class
Phylum Porifera

15. Class Calcarea
 Have
spicules made of
calcium carbonate
 Mostly small in size (<15
cm.), and form irregular
masses
 Never contain spongin,
restricted to shallow water,
and strictly marine
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Phylum Porifera

16. Class Demospongiae (Most sponges)


Have spicules made of silicon
dioxide (SiO2) or spongin or a
combination of both
Most sponges belong to this
class (90%)
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
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Nearly all are leuconoid body
type
Mostly found on the
continental shelf
Spongia spp. (Bath sponge)
Phylum Porifera

17. Class Hexactinellida (Glass
sponges)
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Spicules are made of silica
Usually found in deep water on soft substrates in the
tropics 200-1,000m.
Spicules are six pointed and have a lattice-like
structure
Cup, vase or urn shape
Euplectella (Deep sea Glass sponge)
Phylum Porifera