Phylum Porifera

Sponges

Porifera

• Sponges– Living on Earth for at least 540

million years– Most sponges live in the ocean

• Arctic to the tropics • shallow water to depths of

several hundred meters– They are dry sponges were use

for • Bathing• Cleaning

Porifera

• What is a Sponge?1. Sponges are placed in the phylum Porifera (poh-

RIF-ur-uh) which means “pore-bearers.”• Sponges have tiny openings, or pores, all over their bodies

2. Sponges are sessile, meaning that they live their entire adult life

3. They have irregular symmetry

Porifera

• Why are sponges considered animals?– Sponges are multicellular, heterotrophic, have no

cell walls and contain only a few specialized cells.

Water flow

Porifera: Structure

• Specialized cells of sponges:1. Collar cells or choanocytes – Use flagella to

move a study current of water through the sponge.

2. Osculum – A large hole at the top of the sponge3. Spicule – spike-shaped structure made of

chalklike calcium carbonate or glasslike silica4. Amoebocyte – move around within the walls of

the sponge and carry food to other cells

Porifera: Digestion

• Sponges are filter feeders – take microscopic food particles from the water. – As water moves through the sponge,

food is trapped and engulfed by collar cells (choanocytes) that line the body cavity

– Then, food gets passed to amebocytes who take the food to the rest of the cells in the body

Porifera

• How do they breathe?– Sponges rely on the movement of water through

their bodies to carry out body functions:• Respiration – oxygen obtained from the water• Excretion – removal of wastes into the water

Porifera

• How do they reproduce?– Reproduction can be sexually or asexually.– Adults produce gemmules which can withstand harsh

conditions and grow into an adult sponge– Reproduce asexually by regeneration – tear of a piece

of sponge and a complete new sponge will appear.

Porifera

• How important are sponges to the environment?– Many sponges are large and have irregular shapes

and provide habitats– Commensalism and partnerships

• EX: bacteria provide food and oxygen to the sponge while the sponge provides protected area.

Porifera

• Types of Sponges1. Calcareous sponges

Found in shallow waters around the world Spikes made of calcium carbonate (lime)

Porifera

• Types of Sponges2. Glass sponges• Skeleton consists of crystalline silicon dioxide• Generally found in deep, tropical waters

Porifera

• Types of Sponges3. Demospongiae (Bath sponges)• Skeleton is elastic (spongin) fibers• Found in the Caribbean

Encrusting Sponge

Phylum Ctenophora

Comb Jelly

Ctenophora

• Ctenophores (Greek for “comb-bearers”) have eight “comb rows” of fused cilia arranged along the sides of the animal (red rows)– The cilia beat and propel the animal through the

water

Ctenophora

• Ctenophora are commonly known as comb jellies and are voracious predators– 50 species– Most species are planktonic carnivores and

transparent which feed on zooplankton– Light-scattering cilia and bioluminescence– Lack stinging cells but capture prey by sticky cells

called colloblasts– Favorite food of sea turtles

Ctenophora

• Reproduction– Most are hermaphroditic• Release egg and sperm in water, where sperm must

find the egg to fertilize it• Fertilized eggs develop through larval stage that

hatches into an adult; no medusa stage

Sea gooseberry

Phylum Cnidarians

Hydras, jellyfishes, sea anemones and corals

Cnidarians

• What is a cnidarian (ny-DAYR-ee-n)?1. 10,000 species2. Soft-bodied, carnivorous animals3. Stinging tentacles arranged in circles around

their mouths4. Simplest animals to have radial symmetry and

specialized tissues.

Cnidarians

• Specialized cells of cnidarians1. Cnidocytes – stinging cells that are located along

their tentacles2. Nematocyst – poison-filled, stinging structure

that contains a tightly coiled dart.

Cnidarians

• Form and Function in Cnidarians– Simple organisms and only a few cells

thick– Responses to the environment are carried

out by specialized cells and tissues.

• Life cycle that includes two different-looking stages:1. Polyp stage2. Medusa stage

Cnidarians

• Polyp stage– Cylindrical body with armlike tentacles. – Mouth points upward– Polyps are usually sessile

Cnidarians

• Medusa Stage– Motile– Bell-shaped body– Mouth on the botton

Cnidarians

• How do Cnidarians feed?– After paralyzing its prey, cnidarian pulls the prey

through its mouth into its gastrovascular cacity