Key Vocab 13. Classification of Invertebrates

Front

Sessile

Back

Describes an organism that is fixed in place and does not move freely (e.g., corals, barnacles, sea sponges).

Front

Porifera

Back

A phylum of simple, multicellular, aquatic invertebrates that lack true tissues and organs. They have porous bodies and rely on filter feeding (e.g., sponges).

Front

Sea Sponges

Back

Marine or freshwater invertebrates belonging to the phylum Porifera, characterized by a porous body structure that allows water to flow through for feeding and respiration.

Front

Cnidaria

Back

A phylum of aquatic invertebrates with radial symmetry, specialized stinging cells (cnidocytes), have true tissues, have 1 opening as mouth in digestive track, and two main body forms: polyp and medusa (e.g., jellyfish, corals, sea anemones).

Front

Hydra

Back

A small, freshwater cnidarian that exists in polyp form and reproduces asexually by budding or sexually through gametes. It has tentacles with stinging cells for capturing prey.

Front

Polyp

Back

A body form of cnidarians that is sessile (attached to a surface) and tubular, with the mouth and tentacles facing upward (e.g., corals, sea anemones, hydra).

Front

Annelida

Back

A phylum of segmented worms with a body divided into ring-like segments, a complete digestive system, and a closed circulatory system (e.g., earthworms, leeches).

Front

Earthworm

Back

A terrestrial annelid that plays a crucial role in soil aeration and nutrient recycling by burrowing and feeding on organic matter.

Front

Mollusca

Back

A large phylum of invertebrates with soft bodies, often protected by a calcium carbonate shell, and a muscular foot for movement (e.g., snails, clams, octopuses).

Front

Cephalopod

Back

A class of highly developed mollusks with tentacles, a well-developed brain, and the ability to squirt ink for defense (e.g., octopuses, squids, cuttlefish).