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