Marine Biology: Classification, Ecosystems, and Organisms

Kingdom

The largest classification group of organisms.

Phylum

A classification level below kingdom that groups organisms by major body plans.

Class

A subdivision of a phylum.

Order

A subdivision of a class.

Family

A subdivision of an order.

Genus

A group of closely related species.

Species

The most specific classification; organisms that can reproduce with one another.

Homo sapiens

The scientific (genus and species) name for humans.

Metaphytes

Multicellular plants.

Metazoan

Multicellular animals.

Protists

Mostly single-celled organisms with a nucleus.

Bacteria

Single-celled organisms without a nucleus.

Invertebrate

An animal without a backbone.

Coral

Marine invertebrates that form reefs and have symbiotic algae. (Phylum Cnidaria)

Jellyfish

Free-floating marine invertebrates with stinging cells.

Sea anemone

Sessile marine invertebrates related to corals.

Sponge

Simple aquatic animals that filter feed.

Algae

Photosynthetic organisms found in aquatic environments.

Snail

A mollusk with a single shell.

Clam

A bivalve mollusk with two shells.

Octopus

A soft-bodied mollusk with eight arms. (Phylum Mollusca)

Squid

A fast-swimming mollusk with tentacles. (Phylum Mollusca)

Crab

A crustacean with a hard exoskeleton.

Copepod

Small crustaceans that are a major part of zooplankton.

Barnacle

A crustacean that attaches permanently to surfaces.

Starfish

Marine echinoderms with radial symmetry. (Phylum Arthropoda)

Sea urchin

Spiny echinoderms that graze on algae. Phylum Arthropoda

Shark

Cartilaginous fish and marine predators.

Ray

Flattened cartilaginous fish related to sharks.

Phytoplankton

Microscopic photosynthetic organisms that form the base of marine food webs.

Zooplankton

Small drifting animals that feed on phytoplankton.

Diatom

A type of phytoplankton with silica shells.

Kelp

Large brown algae forming underwater forests.

Trophic level

A feeding position in a food chain or food web.

Biosphere

All ecosystems and living organisms on Earth.

Ecosystem

A community of organisms and their physical and chemical environment.

Environment

The physical, chemical, and biological conditions in which organisms live.

Community

All populations of different species living together.

Population

All individuals of a single species in an area.

Plankton

Drifting organisms unable to swim against currents.

Nekton

Actively swimming organisms (e.g., fish, squid).

Benthos

Organisms that live on or in the seafloor.

Benthic

Referring to the bottom environment of oceans or lakes.

Littoral

The intertidal or wave-affected zone near shore.

Neritic

Shallow ocean water over the continental shelf.

Pelagic

Open ocean waters beyond the continental shelf.

Photic

Water zones that receive some light.

Aphotic

Water zone with no light.

Bathyl

Ocean depths between 200 and 2000 meters

Abyssal

Ocean depths greater than 2000 meters.