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Sexual dimorphism

differences between males and females in external appearance or behavior

Shellfish

aquatic animal with a shell; includes mollusks and crustaceans

Shute

bony plate

Siliceous

containing silica

Siphon

tube or tube-like part of an animal through which air, food or water passes

Slough

swamp, bog, marsh or pond that is part of an inlet or backwater

Smolt

juvenile salmon that has completed rearing in freshwater and migrates into the marine environment. Becomes physiologically capable of balancing salt and water in the estuary and ocean waters.

Solitary

living singly except during breeding and/or raising young

Spawn

to produce and deposit eggs

Species

distinctive group of organisms that can successfully interbreed and produce viable offspring

Species diversity

numbers of different species and their relative abundance in a given area

Spermatophore

capsule enclosing a packet of sperm produced by males of some animals that is directly transferred to the reproductive part of a famale's body

Spiracle

dorsal openings in the head region of some cartilaginous fishes through which water is drawn and passed over the gills

Spiracles

openings that allow entrance, passage, or exit of a gas or vapor, esp. of air

Statocyst

specialized sacs or organs on the rim of the bell and tentacle bases of jellies that assist animal in maintaining balance in the water column by sensing the pull of gravity; balance organ

Stipe

stem-like part of a kelp plant that connects the holdfast to the blades

Stipe

stem-like part of a kelp plant that connects the holdfast to the blades

Stock

a biologically discrete population

Strobilia

multi-organism columnar pancake-like of very small jellies produced by a polyp; as jellies break off, the polyp is said to be 'strobilating'

Strobilization

budding: asexual transformation into reproductive process

Sublittoral (subtidal) zone

benthic zone from the low tide mark to the outer edge of the continental shelf

Subsistence

barest means needed to sustain life

Subspecies

a genetically distinct geographical subunit of a species. Also called race.

Substrate

any surface on which a plant or animal lives or on which a material sticks

Subtidal

below the intertidal, or below the level of the lowest tide. Also called sublittorial.

Supralittoral zone

narrow benthic zone on shores above high water mark that only becomes wet when there are storms or spray

Surfline

area near shore where the waves break

Surge

movement of a mass of water

Surge channel

channel along the edge of rocks or reefs in which the water level fluctuates with wave or tidal action

Suspension-feeder

an animal that filters out debris, detritus, or other particles suspended in the surrounding water

Suspension-feeder

an animal that filters out debris, detritus, or other particles suspended in the surrounding water

Sustenance

nourishment; that which sustains life

Swell

a large ocean wave that moves steadily without breaking

Swim bladder

gas-filled bladder of a fish that helps it maintain its position in the water column

Symbiosis

close relationship between two organisms of different species that is often of mutual benefit

Tactile

pertaining to the sense of touch

Taiga

forest communities found south of the tundra and north of short-grassed plainsst in cold, wet subarctic climates, consisting of a mostly coniferous evergreems (stunted spruces, firs) with birches and aspens found in drier locales.

Taxonomy

science of classifying organisms in established categories according to their biological and evolutionary characteristics; nomenclature is usually Greek or Latin in derivation

Temperate zone

moderate temperature area located between the polar and tropical zones

Tentacles

long, cylindrical projections from an organism, specialized as sensory, grasping and food collecting structure

Terrestrial

pertaining to plant or animal life on land rather than in water

Territory

area with defined boundaries established and defended by an animal, usually for breeding and/or foraging

Test

shell or casing of an organism. Skeleton of a sea urchin.

Tetrapod

animals that are four-limbed (two pairs): includes amphibians, reptiles, birds, mammals

Tetrodotoxin

neurotoxin that acts specifically on nerve cells, commonly causing paralysis, especially tetrodotoxin, bactrachotoxin, and compounds found in the toxins of some bees, scorpions, and spiders

Thermocline

water layer in which temperature changes rapidly with increasing depth

Thorax

portion of the body between the head and abdomen; the chest region

Tide

periodic rise and fall of oceanic water levels (usually twice daily) along a shore caused by the unequal gravitational pull of the sun and moon on different parts of the rotating earth

Tide pool

pool of water left along the shore as the tide level falls

Tidemark

high water mark left by tidal water