2.Sponges

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Sponges
Phylum Porifera
Phylum Porifera – Pore Bearers
Water flow
Osculum
Central cavity
Pores
Choanocyte
Spicule
Pore cell
Pore
Epidermal cell
Archaeocyte
• Groups of specialized cells, do not form true tissues or
organs
• Sessile-attached to surface
• Pores allow water/plankton to circulate
(suspension/filter-feeders)
• Asymmetry
• Choanocytes – collar cells that pump water in with
flagella, create currents and trap food particles
• Osculum – large opening for water to exit
• Feeding, circulation, excretion, respiration
• Simple skeleton
– Spicules – transparent support structures made of
calcium carbonate/silica
– Spongin - protein
– Amebocytes – mobile cells to secrete spicules and
Feeding
• Suspension/Filter feeders-actively filtering
food particles
• Intracellular digestion
• Choanocytes trap food/pass it on
• Amebocytes – complete digestion by
transporting and storing food particles
Respiration, Feeding,
Excretion
• Water circulation
• diffusion
Response
• Lacks nervous system
• Produce toxins
Sexual Reproduction and Life
Cycle
MEIOSIS
Sperm from a sponge are
released into the surrounding
water-Spawning. Water currents
carry the sperm to other
sponges.
Haploid (N)
Diploid (2N)
New sponge
Sperm (N)
Mature sponge
Metamorphosis (2N)
Egg (N)
Swimming larva
The zygote
develops into a
free-swimming
larva. Water
currents carry the
larva until it
attaches to a
surface and grows
into a new sponge.
Larva (2N)
Sperm enter another sponge
through pores. The sperm are
carried to eggs inside the body
wall. Sperm fertilize eggs.
FERTILIZATION
Reproduction – Cont.
• Sexual Reproduction
Gametes-sex cells developed from certain
amebocytes (most sponges can produce both)
• Asexual Reproduction
Budding-branches or buds break off and grow
into separate sponges identical to parent
Types of Sponges
• Encrusting-form thin growths on
rocks/dead coral (sometimes bright colors)
Red bearded sponge
• Glass-anchored in deep-water
sediments, lace-like skeleton of fused
spicules (ex. Venus Flower Basket)
• Boring-bore thin channels through
calcium carbonate shells such as
oysters and coral
• Coralline/Sclero-calcium carbonate
skeleton with spicules and spongin form
under its body (first known as fossils)
Ecology
• Symbiotic relationships with bacteria,
algae, protists
• Habitats
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