PORIFERA
Porifera
Have specialized cells, but no tissues
2 cell layers
Asymetrical
Marine and
freshwater
Sessile as adults
Larvae are motile
Bodies are filled with pores for water circulation
Water exits thru the…….
choanocytes
Feeding
Sponges are filter feeders
Food particles stick to collar of choanocytes where it is digested
Amebocytes are specialized cells in sponges that can roam to
pick up food from choanocytes & distribute it to all other parts of
the sponge
They also transport carbon dioxide & wastes away from sponge cells
Sponges have no mouth, guts, tissues, or organs
There functions are carried out by a few specialized cells systems
Sponges carry out basic functions, such as feeding and circulation, by
moving water through their bodies
Still, if you carve ‘em up, they come back for more!!
It’s more amazing than that. If you mix groups of sponges together,
they will usually reorganize into their original groups.
Reproduction: Asexual vs. sexual
Damage to a sponge can actually promote asexual reproduction, as
“parts” can land elsewhere and form new sponges.
Sponges have a simple skeleton
Some skeletons are made of
tiny Spicules, which are spiked
shaped structure made of
calcium carbonate or glasslike silica
Other support structures are
made of Spongin
(flexible protein fibers)
Sponge sizes
Porifera reproduction
Asexually:
by external buds that break off & form new sponges
or stay attached to form sponge colonies (budding)
Sexually:
Video clip
Sponges are hermaphrodites
(produce both eggs & sperm)
they exchange sperm & cross-fertilize
eggs during sexual reproduction
Free-swimming larva that forms from the
Zygote, eventually settling on the bottom for a
sessile life