PHYLUM PORIFERA
Sponges are
- simplest
invertebrate animal
- more than 5,000
species
- mostly marine,
some fresh
Their bodies contain pores - thus the name “Porifera”.
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They are multicellular but organized at the cellular level only without tissues or organs.
Beating flagella pump water through the pores bringing food and
oxygen. Sponges can pump volumes of water up to 20,000 times
their own volume.
This cleans the oceans as the sponges feed on bacteria and
plankton.
Reproduction may be
sexual or asexual.
Asexual is by external
buds or internal
gemmules. Sexual is
by broadcasting
gametes into the water.
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The meroplanktonic larvae settle into sessile adults.
Three kinds of sponges have supporting structures called spicules
composed of:
1. calcium carbonate
spines
2. silica spines
3. elastic fibers called
spongin - only this
type is used for
commercial sponges
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PHYLUM CNIDARIA
ex: (jellyfish, anemones, corals)
- two tissue layers - an outer
epidermis and inner gastroderm
- nerve net with stinging capsules
called nematocysts
- radial symmetry with 2 body types:
1. polyp
2. medusa
Sea Anemone
Portuguese man-of-war
a colonial Cnidarian
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The Man-of-War has a gas filled float and individuals that function
like specialized organs. Some are carnivores with digestion in
food vacuoles.
The coral animal may live as a free-floating polyp or build colonies
into reefs, but not all corals build reefs.
1. stony coral hermatypic or reef
builders. The polyp
grows in 6 parts to
form a body of calcium
carbonate
ex: brain, staghorn,
golf ball
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2. soft coral - polyps with 8
tentacles
While part of the reef, they
do not build reefs because
their bodies are a soft
keratin.
ex. sea fans, gorgonians
3. hydrocoral - false corals resemble the
anemone and contain powerful
neumatocysts that cause skin irritation
ex: fire coral
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CORAL BLEACHING
• Coral bleaching,
occurs when heat
drives out algae living
within coral tissues
• indicator of stress that
could eventually kill
coral populations
• Upper temperature
limits 30-35 C
• If temperature returns
to normal quickly,
coral recovers,
otherwise coral dies
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