Invertebrate Test Review: Sponges and Cnidaria

Calcarea

A type of sponge in the phylum Porifera.

Hexactinellida

A type of sponge in the phylum Porifera.

Demospongiae

A type of sponge in the phylum Porifera.

Homoscleromorpha

A type of sponge in the phylum Porifera.

Sessile

An organism that is fixed in one place and does not move (e.g., attached to a surface).

Porifera

A phylum that includes sponges, which can regenerate body parts.

Cnidaria

A phylum that includes organisms like hydra, which can regenerate body parts.

Ostia

Small pores through which water enters a sponge.

Osculum

A larger opening through which water exits a sponge.

Spicules

Skeletal elements made of calcium carbonate or silica found in sponges.

Spongin

A protein fiber that can be part of a sponge's skeleton.

Choanocytes

Collar cells in sponges that create water currents and trap food.

Amoebocytes

Cells in sponges that transport nutrients and produce skeletal elements.

Pinacocytes

Cells that form the outer layer of the sponge.

Porocytes

Cells that form the ostia (pores) for water entry in sponges.

Radial symmetry

The symmetry characteristic of Cnidaria.

Gastrovascular cavity

Another name for the Hollow Gut in Cnidaria.

Hydrozoa

A class of Cnidaria that includes hydra.

Scyphozoa

A class of Cnidaria that includes jellyfish.

Anthozoa

A class of Cnidaria that includes corals and sea anemones.

Cnidocytes

Stinging cells found in Cnidaria.

Nematocyst

The harpoon used by Cnidocytes in Cnidaria.

Polyp

The sessile stage in the life cycle of Cnidaria.

Medusa

The free-swimming stage in the life cycle of Cnidaria.

Gastropoda

A class of Phylum Mollusca that includes snails.

Bivalvia

A class of Phylum Mollusca that includes clams.

Cephalopoda

A class of Phylum Mollusca that includes octopuses.

Polyplacophora

A class of Phylum Mollusca that includes chitons.

Scaphopoda

A class of Phylum Mollusca that includes tusk shells.

Soft body with a muscular foot

One of the characteristics of Mollusca.

Mantle that secretes the shell

One of the characteristics of Mollusca.

Radula

A feeding structure found in Mollusca, except in bivalves.

Gills for respiration

A characteristic of Mollusca.

Open circulatory system

A characteristic of Mollusca, except in cephalopods.

Coelomate body cavity

A characteristic of Mollusca.

Porifera

Phylum with poor swimmers; sponges are sessile and do not swim.