Glossary

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Toxin
any substance harmful to living cells
Trophic
pertaining to growth or nutrition
Tube feet
extension of the water vascular system of echinoderms (sea stars, sea urchins, etc.) that aids in locomotion, grasping and feeding
Tundra
treeless, level or rolling ground above the timberline of spruces and firs in polar regions (Arctic tundra) or on high mountains (alpine tundra), characterized by bare ground and rock or by such vegetation as mosses, lichens, small herbs, and low shrubs.





Turbid
stirred up sediment; cloudy
Turf
thick mat of plants and animals on a substrate
Undulate
to move back and forth in a wave-like motion
Unicellular
single-celled
Upwelling
deep, cold, nutrient-rich waters that rise to the surface from deeper areas of the ocean
Urticating hair
barbed hairs that cover the dorsal and posterior surface of a tarantula's abdomen
Vascular plants
plants that have vessels to conduct and circulate fluids around their parts
Vasculated
having numerous blood vessels
Velum
shelf or rim that projects inward around the margin of the bell of a hydozoan, partially closing the opening
Venom
a toxin injected into a victim
Ventral
toward the lower side or belly; underside; opposite of the dorsal side
Vertebrate
animal with a backbone: having a dorsal column of vertebrae
Vertical migration
periodic movement of an animal up and down the ocean's water column
Vertical zonation
distinct banding of groups, populations or organisms at different levels of a habitat
Vestigial
usually a non-functioning remnant of a body part that once existed as a fully functioning part of an organism
Vibrissa
whisker(s) of mammals, plural: vibrissae
Viviparous
producing living young that develop from eggs retained within the mother's body, receiving nourishment through the placenta
Warm-blooded
body temperature is controlled internally and is maintained at a constant level; endothermic
Water column
vertical depth of water; area between the surface of the ocean and the ocean floor
Water vascular system
system of fluid-filled canals and structures that aid in locomotion and food gathering
Wetlands
biologically productive areas b ordering estuaries, salt marshes and swamps that are occasionally flooded by tidal or river
Whorl
single turn of a spiral shell of a mollusk. A body whorl is the msot recently formed turn of a spiral shell terminating in an aperture.
Wild salmon
salmon that have spent their entire life cycle in the wild and originating from parents that were also produced by natural spawning and continuously lived in the wild
Wrack
any marine vegetation cast up on the shore by wave action, example, kelp
Zero tide
average of the lower low tides
Zonation
distribution of the plants and animals in a community into recognizable, distinctive zones
Zooanthellae
photosynthetic microorganisms that live symbiotically in the tissues of organisms such as corals and jellies
Zooplankton
planktonic animals suspended in the water column
Zygote
fertilized egg