Chapter 9
Porifera, Cnidaria, Ctenophores
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Porifera
(sponges)
9,000 species
3 classes
No tissues or organs
Noxious odor & tastefew predators
Cell Types
• Pinacocytes- line the
outer surface
• Porocytes- regulate
water circulation
through body wall
• Choanocytes- collar
of cells surrounding a
flagella. Flagella
creates water current
and collar absorbs
food particles
Body Structures
• Spicules- needle-like
spines in skeleton
• Spongin- soft, fibrous
protein (makes
commercial sponges)
3 Body Forms
• Ascon- simplest.
Tubular body w/
central canal
• Sycon- radial canals.
Thicker, more
complex body wall.
• Leucon- largest and
most complex. More
collar cells.
Asconoid Sponge
Osculum
Spongocoel
Ostium
Porocyte
Syconoid Sponge
Osculum
Incurrent Canal
Spongocoel
Radial Canal
Ostium
Choanocytes
Syconoid Sponge
Scypha (Grantia) xs
Spongocoel
Radial Canal
Choanocytes
Incurrent Canal
Ostium
Leuconoid Sponge
Osculum
Excurrent canal
Incurrent pore
Incurrent canal
Choanocyte
chamber
Class Calcarea
Grantia
• Small
• Vase shape
• Spicules of calcium
carbonate
Class Hexactinellida
Euplectella
• Spicules
– Siliceous
– 6 rays
Class Demospongiae
Spongia
• Spicules
• Spongin
Porifera Platyhelmithes Mollusca Arthropoda
Cnidaria
Nemertea
Annelida
Echinodermata Hemichordata
Lophophores Chordata
Precambrian
Protozoans
Before 670 MYA
CO 12
The
End