Sponges

Phylum Porifera

Phylum Porifera – Pore Bearers

Water flow

Choanocyte

Spicule

Pore cell

Pore

Epidermal cell

Archaeocyte

Osculum

Central cavity

Pores

• 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

spongin

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

Sperm from a sponge are released into the surrounding water-Spawning. Water currents carry the sperm to other sponges.

Sperm enter another sponge through pores. The sperm are carried to eggs inside the body wall. Sperm fertilize eggs.

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.

Sperm (N)

Egg (N)

Larva (2N)

Mature spongeMetamorphosis (2N)

Swimming larva

New sponge

Haploid (N)

Diploid (2N)

FERTILIZATION

MEIOSIS

Reproduction – Cont.

• Sexual Reproduction

Gametes-sex cells developed from certain amebocytes (most sponges can produce both)

• Asexual ReproductionBudding-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