Glossary

biodiversity
The variety and interdependence of all living things. Biodiversity includes all living organisms, the genetic differences among them, the communities, cultures, habitats and ecosystems in which they evolve and coexist, and the ecological and evolutionary processes that support them.

bioluminescence
Light produced by a chemical reaction within an organism.

biomass
Organic (carbon-based) tissue in living or dead form. For example, the biomass of trees in a forest, the biomass of fishes in a volume, the biomass converted to waste, or the biomass of microorganisms in a soil sample describe the overall content of matter in various components of an ecosystem.

biosphere
The totality of living things on Earth, along with their habitatsóthe largest ecosystem.

carbon cycle
The continual exchange of organic matter from one form to another, including living and dead tissue, gases, and minerals.

Cnidaria
A phylum comprising four taxonomic classes: Hydrozoa (hydroids), Cubozoa (sea wasps and box jellies), Scyphozoa (jellyfish), and Anthozoa (corals and sea anemones). Hydroids are considered the most primitive of the four classes; the other three classes probably evolved from hydroids. Scyphozoa spend most of their lives in the medusa stage, while Anthozoa spend most of their lives as polyps.

comb jelly
A group of about 90 species in the phylum Ctenophora that are abundant in the open ocean. They are transparent, bilaterally symmetrical, usually several centimeters long, and structurally more complex than cnidarians. They propel themselves using eight plates of cilia, from which the name ìcomb jellyî is derived.

conservation
The management and protection of the natural world.

ctenophora
See comb jelly

ecosystem
A community of interacting organisms and their physical environment.

food web
The interconnected group of organisms through which energy, in the form of food, is passed. An entire food web includes all the interconnected feeding relationships in an ecosystem.

Invertebrate
An animal without a backbone.

jelly
A common term for gelatinous invertebrates that float freely in the ocean. Jellies comprise a vast number of species found predominantly in four phyla: Cnidaria, Ctenophora, Mollusca, and Chordata (subphylum Urochordata).

jellyfish
Approximately 200 transparent or translucent marine species in the phylum Cnidaria and class Scyphozoa that spend a majority of their life in the medusa stage that follows an immature, polyp stage. Medusae have a central, radially symmetric bell (or ìmedusaî) and tentacles called nematocysts that hang below in order to stun and ensnare prey.

luciferase
The enzyme that catalyzes the reaction of a luciferin molecule with oxygen.

luciferin
A class of compounds found in animals capable of bioluminescence; luciferins emit light upon reaction with oxygen.

marine snow
The dead and decaying organic matter derived from plants and animals that drifts and falls through the open ocean.

medusa
The bell-shaped, sexually mature stage of cnidarians, especially scyphozoans (jellyfish) which spend most of their life cycle in the
medusa stage.

mesoglea
The soft tissue found between the inner and outer walls of cnidarians and ctenophores.

photoprotein
A molecule containing luciferin, luciferase, and an ion such as hydrogen or calcium; when stimulated, a photoprotein emits light in bioluminescent animals.

phylum
A major grouping of species with similar special characteristics. An example is the arthropods, a phylum that includes insects, spiders, scorpions, millipedes, crabs, and other jointed-leg animals.

polyp
The larval stage of Cnidarians

systematics
The science of identifying, describing, naming, and classifying groups of organisms and studying their genealogical histories.

taxon (pl. taxa)
Any group in the classification of life, such as a family, phylum, or species.