Marine Inverts Practical Study Guide 2026

These flashcards cover key terms and concepts related to marine invertebrates, their classification, habitats, and species interactions as outlined in the study guide.

Species Identification

The process of recognizing and classifying organisms based on their characteristics and taxonomy.

Phylum

The taxonomic rank below Kingdom and above Class, used to classify a group of related organisms.

Class

A rank in the biological classification system, below Phylum and above Order, grouping together organisms that share specific characteristics.

Genus

The taxonomic category that ranks above species and below family, often used to group species that are closely related.

Species

The basic unit of biological classification, identifying a group of organisms that can interbreed and produce fertile offspring.

Habitat Types

Different environments where species can be found, such as rocky intertidal zones, mudflats, and open oceans.

Epifauna

Organisms that live on the surface of the substrate in marine environments.

Commensalism

A type of species interaction where one organism benefits while the other is neither helped nor harmed.

Predation

An interaction where one organism (the predator) kills and eats another organism (the prey).

Cnidaria

A phylum of aquatic animals, including jellyfish, corals, and anemones, characterized by stinging cells called nematocysts.

Mollusca

A diverse phylum of invertebrate animals that includes snails, clams, and octopuses, known for their soft bodies and often hard shells.

Annelida

A phylum of segmented worms, including earthworms and leeches, characterized by their ringed body structure.

Arthropoda

A phylum of invertebrates that includes insects, arachnids, and crustaceans, characterized by jointed limbs and exoskeletons.

Echinodermata

A phylum of marine animals such as starfish and sea urchins, characterized by a radial symmetry and a water vascular system.

Demospongiae

A class within the phylum Porifera, which includes the majority of sponge species.

Hydrozoa

A class of mainly colonial aquatic animals within the phylum Cnidaria, known for their complex life cycles.

Malacostraca

A class of crustaceans within the phylum Arthropoda, including crabs, lobsters, and shrimp.

Gastropoda

A large class of mollusks that includes snails and slugs, characterized by a single, usually spirally coiled shell.

Bivalvia

A class of mollusks with two-part hinged shells, including clams, oysters, and mussels.

Hexacorallia

A class of Cnidaria that includes corals with a body divided into multiples of six.

Intertidal Zone

The area between the high tide and low tide marks, where organisms are exposed to air at low tide and underwater at high tide.

Invasive Species

Non-native species that adversely affect the habitats and bioregions they invade.

Commensalist Relationship

An interaction between two species in which one benefits and the other is unaffected.