TERRESTRIAL ECOSYSTEMS
Biomes: very large ecosystems that contain a
number of smaller but related ecosystems
within them (there are 7 major biomes)
--seldom have distinct boundaries
(topography changes)
--climate largely responsible for biome
characteristics
TUNDRA
--cold and largely treeless biome
--forms a continuous belt across northern
North America, Europe & Asia
--largest & northernmost biome
--characterized by permafrost (layer of
permanently frozen soil under the surface)
--poor soil; mosses, grasses, sedges lichens,
dwarf woody plants
TAIGA
--south of the tundra, across the globe
--forested biome (conebearing trees)
--pines, firs, hemlock, spruce
--moose, bears, wolves, lynx
--long, cold winters
TEMPERATE DECIDUOUS FOREST
--trees lose all their leaves in the fall
--North America, Europe; parts of Asia, and
the southern hemisphere
--warmer winters and longer summers than
taiga; more precipitation
--pronounced seasons, even precipitation
--birch, beech, maple, oak, etc.
--white-tailed deer, foxes, raccoons,
squirrels, etc.
TEMPERATE GRASSLANDS
--dominated by grasses, in the interior of
continents; very rich soil
--same latitude as deciduous forests; not
enough precipitation to support trees
--prairie/steppes/pampas/veldt are all
grasslands
DESERT
--receive <25 cm (10 in.) rain/year
--not always hot
--vegetation adapted to prevent water loss
(creosote bush, saguaro)
SAVANNAS
--tropical or subtropical grassland (best
known in Africa, but in S.A. and Australia too)
--alternating wet and dry seasons
--large numbers of herbivores; gazelles,
zebras, giraffes, etc.
TROPICAL RAIN FOREST
--found near the equator
--year-round growing season; abundant
rainfall
--greatest diversity of all biomes; probably
contain ~1/5 of the world’s known species
AQUATIC ECOSYSTEMS
OCEANS
--covers ~70 % of Earth’s surface
--average depth of 2.3 miles; deepest parts
are about 6.8 miles deep
--~3 % sale
--divided into zones of both depth and
distance from shore
estuaries—occur where freshwater rivers and
streams flow into the sea (bays, salt marshes,
mud flats)
FRESHWATER--less than 0.005 % salt
Lakes & Ponds:
--are either eutrophic or oligotrophic
eutrophic: rich in organic matter and
vegetation
--waters relatively murky
oligotrophic: contain little organic matter
--water much clearer
--bottom usually sandy or rocky
Rivers & Streams
River: body of water that flows down a
gradient (slope) toward its mouth
--plants and wildlife must be adapted to
withstanding powerful currents in fast-moving
rivers; slow rivers richer in nutrients