Phylum Porifera
General Characteristics
SPONGES!
Simplest of all animals
_________________
No true tissues or organs
_________________________
Marine and Freshwater
Saltwater are colorful
Freshwater are dull green color
General Characteristics Cont.
•
•
•
•
Sponges are sessile as adults
Free swimming larval stage called dipleurula
Porifera means pore-bearing
Water enters through pores bringing in food
and oxygen
• ____________________________
• Osculum- large opening at the top where
excess water leaves
WATER OUT
Water Flow
Through the
Sponge
WATER IN
Osculum
3 Basic Cell Types
1. _______________
2. Mesenchyme Cells
3. Choanocytes
3 Basic Cell Types
• 1. Pinacocytes- flat cells that line the
outer surface of the sponge.
–May be slightly contractile
–____________: a specialized type of
pinacocyte; are tube-like in shape;
contractile; and can regulate water
circulation.
2. Mesenchyme Cells- move
around in the mesohyl layer; are
specialized for reproduction,
secreting the skeleton,
transporting/storing food.
____________: jelly-like layer just
underneath the pinacocyte layer.
• 3. Choanocytes- flagellated cells that
line the inner chamber of the sponge;
called collar cells.
–Flagellum: flagella spins to create
water currents to pull in water and
food
–Collar: __________________________
(plankton) from the water
Choanocyte
Choanocyte
__________________________
Consists of either one or all of the
following:
Spicule: microscopic needle-like
spikes that are made of Calcium
carbonate (CaCO3) or silica (glass).
Spongin: a fibrous protein made of
collagen
Sponge Skeletons
Silica Spicules
Limestone Spicules
SPONGIN
Sponge Body Types
• 3 Kinds–Ascon
–__________
–Leucon
Ascon
• ____________________
• Are vase-like
• Least common type of sponge
________________
• Sponge wall is folded into canals
• Choanocytes line the
radial canals to
move water
Leucon
• Have an extensively branched canal system.
• ___________________________
• Multiple ostia
for water to exit
• Increased surface
area means more
water can move
through sponge
Body Forms Summary
Reproduction
Sexual Reproduction- sponges are
monoecious (male and female in the
same body)
Release sperm and eggs into the
water from the Osculum
Cross-Fertilization takes place in the
ocean
_____________________________
Reproduction
Sponge
Releasing Eggs
& Sperm
Reproduction Cont’
o Sponges can regenerate (regrow) lost
body parts through mitotic cell division
(asexual)
o Sponges also reproduce asexually by
________________
Reproduction Cont’d
gemmule
Asexual Reproduction- involves the
formation of gemmules
______________: resistant capsules that
sponges release to survive unfavorable
conditions.
 When conditions become favorable, the
gemmules sprout into sponges.
_____________________
• Phylum Porifera
–3 Classes
• Class Calcarea
• Class Hexactinellida
• Class Demospongiae
Class Calcarea
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•
•
•
Spicules made of Calcium Carbonate
Can have all three body forms
__________________
Ex. Grantia
Class Hexactinellida
• ___________________________
• Can have syncon or leucon body
forms
–Often fused into an intricate lattice
–Glass sponges
Class Demospongiae
• Spicules made of silica, spongin, or
both.
• ____________________
• Ex: common bath sponge