Download Phylum Porifera: Sponges

Biology 11
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Name means “pore bearers”- body has many
pores in it
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Sessile
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Multicellular
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Mostly marine (only 100/9000 are freshwater)
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Asymmetrical body shape
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Made of 2 cells layers
◦ Ectoderm
◦ Endoderm
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No specialized tissue or organ systems
◦ Individual cells sense and react to environmental
changes
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Do have specialized cells that fulfill the sponge’s
life functions
◦ Epidermal cells
◦ Pore cells
◦ Collar cells
◦ Amoebocytes
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Epidermal cells form outer covering
Water is drawn in through pore cells into a
central cavity
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The collar cells have flagella that beat to create a
current to make sure water is being drawn in
through pore cells
Water flows out of sponges through a larger
opening called the osculum
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Make spicules
◦ Needle-like structures that provide structural
support
◦ Made of silica or calcium carbonate
◦ Some made of spongin protein (softer
skeleton)
Carry nutrients to other cells
 Aid in reproduction
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Contain a flagellum to move water in
Brings oxygen and food particles into
body of sponge
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Water acts as the circulatory, respiratory,
reproductive, and excretory systems
Brings in food, oxygen, carries away waste,
gametes, larvae
Oxygen is brought in and carbon dioxide and
other metabolic wastes are given off
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Feeding and Digestion
◦ No mouth or digestive tract
◦ Are filter feeders- sift food particles from the water
 Driven by water flow
 Filtered by collar cells
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Excretion
◦ Driven by water flow
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Respiration
◦ Oxygen diffused from surrounding water into
cells
◦ Carbon dioxide diffused from cells to
surrounding water
 Movement
◦ Adults sessile: Remain attached,
don’t move
◦ Larvae are mobile
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Sexual
Most are hermaphrodites (produce
both egg and sperm)
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Sperm released out of osculum and
swim to another sponge (with the help
of currents)
◦ Enter another sponge’s pore cell
◦ Picked up by collar cells
◦ Carried to an egg by amoebocytes
◦ Fertilization occurs
◦ Zygote develops into a flagellated larvae
which is mobile (can be dispersed)
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Increase change of fertilization
They do not fertilize their own eggs with their
own sperm
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Can also reproduce asexually by:
◦ Fragmentation: part of sponge breaks off
◦ Budding: mitotic growth and break off
◦ Gemmules: collection of cells that are
enclosed by hard outer covering contain
spicules
 Form when conditions are unfavourable
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Provides habitat for many other animals
◦ Like snails, shrimp, sea stars, bacteria…
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Is a food source for other animals
Provides a symbiotic relationships with
bacteria (bacteria provide food and oxygen to
sponge and remove wastes)
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Used as bath sponges
Produce chemicals (to discourage other
animals from eating them) that are being
used in research for cancer, viruses, and
antibiotics