1.
aquaculture: the farming of water organisms
2.
biodiversity: the number of species in an area
3.
biome: a region with a certain climate and certain forms of vegetation
4.
canopy: a leafy roof formed by tall trees in a forest
5.
captive breeding: the mating of animals in zoos or wildlife preserves
6.
clear-cutting: the process of cutting down all the trees in an area at once
7.
coniferous tree: a tree that produces its seeds in cones and that has needle-shaped leaves
8.
coral reefs: a structure of calcite skeletons built up by coral animals in warm, shallow ocean water
9.
deciduous tree: a tree that sheds its leaves and grows new ones each year
10.
desert: an area that receives less than 25 cm of rain per year
11.
endangered species: a species in danger of becoming extinct in the near future
12.
estuary: a habitat in which the fresh water of a river meets the salt water of the ocean
13.
extinction: the disappearance of all members of a species from Earth
14.
fishery: an area with a large population of valuable ocean organisms
15.
grassland: an area populated by grasses and other nonwoody plants most grassland get 25 to 75 cm of rain each year
16.
habitat destruction: loss of a natural habitat
17.
intertidal zone: an area that stretches from the highest high-tide line on land out to the point exposed by the lowest low tide
18.
kelp forests: marine ecosystem where large, brown algae called giant kelp grow
19.
keystone species: a species that influences the survival of many other species in an ecosystem
20.
neritic zone: the region of shallow ocean water over the continental shelf
21.
permafrost: permanently frozen soil found in the tundra climate region
22.
plankton: tiny algae and animals that float in water and area carried by waves and currents
23.
poaching: illegal killing or removal of wildlife
24.
renewable resource: a resource that is either always available or is naturally replaced relatively quickly
25.
savanna: a tropical grassland with scattered clumps of trees
26.
selective cutting: the process of cutting down only some trees in an area
27.
sustainable yield: amount of a renewable resource harvested regularly without reducing future supply
28.
threatened species: a species that could become endangered in the near future
29.
tundra: a polar climate region, found across northern Alaska, Canada, and Russian, with short, cool summers and bitterly cold winters; an extremely cold, dry biome
30.
understory: a layer of shorter plants that grow in the shade of a forest canopy
