Terms and Definitions
aboral - on a two-sided invertebrate, the surface opposite the mouth
algae — (s. alga) - simple aquatic plants. Unlike other plants, algae have no roots, leaves, or stems.
calcareous - containing calcium carbonate (a compound of calcium)
chelipeds - a clawed thoracic appendage found in decapod crustaceans
chitin (KI-t'n) - a hard substance in the external skeleton of arthropods
class - a division of animal or plant classification. A class is a subdivision of a phylum.
crustacean - an arthropod of the class Crustacea, including mostly aquatic forms such as lobsters, crabs, shrimps, and barnacles
detritus (de-TRI-tus) - tiny pieces of dead and decomposing plants and animals
dorsal - pertaining to the back or top surface of the body
ecosystem - a unit of plants, animals, and non-living components of an environment that interact
environment - one's surroundings
evagination - the acts of pushing out, as when sea stars evert their stomachs during feeding
intertidal zone - the shoreline area within the tidal range
invertebrate - any animal that lacks a spinal column
gamete - a male or female reproductive cell
kelp - large brown marine algae, including giant kelp
marine - related to the seas or oceans
oral - of or pertaining to the mouth
order - a division of animal or plant classification. An order is a subdivision of a class
papulae - the tiny external respiratory organs of sea stars
parasite - an organism that lives in or on, and feeds on, a host organism, harming the host
pedicellariae - tiny, pincherlike projections found on the dorsal surfaces of some sea stars
phylum — (pl. Phyla) - a division of animal or plant classification. A phylum is a subdivision of a kingdom.
piling - a column made of wood, steel, or concrete that holds up a dock, wharf, or pier
plankton - free-floating, microscopic plants and animals
predator - an animal that eats another animal
prey - an animal eaten by another animal
radula - a ribbonlike structure bearing rows of teeth found in the "mouths" of many molluscs. The molluscs use their radula for rasping and scraping.
substrate - the surface upon which an organism lives
sessile - attached to the bottom or another hard substrate
territorial - establishing and defending a particular territory
telson - the last segment of the thorax of an arthropod or an extension of the last segment such as a scorpion's stinger or a lobster's tail fan
tidal range - the difference between the highest and lowest tides
tide - the rise and fall of the sea level along the coasts, caused by the gravitational pull of the sun and moon
uropods - in some crustaceans, a flattened pair of appendages at the posterior end of the abdominal section
ventral - pertaining to the underside or bottom surface
