Sponges

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Kingdom Animalia
Phylum Porifera

Characteristics of Sponges

· Simplest animals, multicellular
· No organs or body systems
· Cellular digestion
· Asymmetry

· Filter Feeders· Sessile (do not move)
· Reproduce sexually (sperm and eggs)
· Reproduce asexually (regeneration)
· Skeleton composed of spongin (soft) and spicules (hard)

Sponge Anatomy

Amebocytes - cells within the sponge that move around supplying nutrients and taking away waste

Choanocytes (collar cells)

· layer of cells with flagella
· the movement of the flagella keeps a water current going in the sponge
· food vacuoles in the collar cells digest plankton and other small organisms (filter feeder)

Oscula - large opening at top of sponge, water exits
Ostia - small openings at the side, water enters

Cnidarians

Kingdom Animalia
Phylum Cnidaria

Examples: Jellyfish, hydra, sea anemone, coral, portuguese man of war

Characteristics of Cnidarians
· Tentacles
· Cnidocytes (stinging cells)
· Nematocysts (barbs)
· Gastrovascular cavity (digestion)
· Most are radial symmetry, some have asymmetry (corals)

Cnidarians have two body forms

Medusa - swimming, cup-shaped

Examples: jellyfish, portuguese man of war

Polyp - stationary, vase-shaped

Examples: hydra, coral, sea anemone