Phylum Porifera€¦ · Phylum Porifera (Sponges) What is a sponge? • sessile aquatic animals • Approx 5000 species • Mainly marine, some freshwater • Worldwide in distribution,
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Phylum Porifera(Sponges)
What is a sponge?
• sessile aquatic animals
• Approx 5000 species
• Mainly marine, some freshwater
• Worldwide in distribution, mainly in quiet, clear
waters; all depths and temperatures
Anatomy
• Simple water-flow
system covers
feeding, respiration,
excretion,
reproduction
Anatomy
• Simple water-flow system covers feeding, respiration, excretion, reproduction
• Some specialized cells
• No nerves or muscles but can move in a coordinated way
Types of Sponges
• Calcarea – calcite
spicules; may have
heavy skeleton; no
spongin
Types of Sponges
• Glass sponges
(Hexactinellida) light
reinforcement of silica
spicules; no spongin
Types of Sponges
• Demospongia: silica spicules,
may have heavy skeleton;
have spongin
Types of Sponges
• Demospongia: 90% of all sponges
• All large sponges
• Includes the bath sponges
Feeding
• Mainly filter feeders
• some have autotroph symbionts (green algae and cyanobacteria)
• a few are carnivorous “The prey, mostly small
crustaceans and other invertebrates provided with setae or thin appendages, is trapped on the surface of appendages of the sponges, which is lined by tiny hook-like spicules acting asVelcro. Then the cells of the sponge migrate towards the prey, andindividually phagocytize and digest fragment of the prey. ”
Reproduction
• Asexual:– Budding
– Fragments
– Produce gemmules “ ‘survival pods’ which a few marine sponges and many freshwater species produce by the thousands when dying and which some, regularly produce in autumn. shells of spongin, often reinforced with spicules, around clusters of cells full of nutrients. ”
Reproduction
• Sexual:
– Most are hermaphrodites (produce both eggs
and sperm)
– Most release sperm into the water and retain
eggs until hatched
– Eggs hatch into larvae that float for a few
days, then settle and transform
Evolution
• Choanoflagellates are
protists which strongly
resemble the main
cells of sponges
• These joined in
colonies to form first
multio-cellular
animals
Relationships
• Once thought ancestral to all multicellular
animals
• Now not so clear
• Sponges may not be a coherent group with
one common ancestor
• Still - very close to the FIRST multicellular
animals
Fossil History
• Chemical traces from
1,800 million years
ago (MYA)
• Well-preserved
sponges from 580
MYA
Use
• Dolphins put sponges on
noses
• “Worn like a sort of glove, a
sponge appears to protect a
dolphin when it pokes around
on the bottom of the bay ” -http://www.sciencenewsforkids.org/articles/20
050615/Note2.asp
• Learned behavior
Use
• People – 2 species used for bath sponges,
painting, padding, filtering, even
contraception
• These nearly collected
to extinction
• Now largely replaced
by plastics
Use
• People – sponges produce many chemicals,
some may become useful medicinally
References
• http://en.wikipedia.org/wiki/Sponge
• http://www.sciencenewsforkids.org/articles/20050615/No
te2.asp
• textbook
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