Chapter 6 Summary
APES
Campbell Jones
Major Ecosystems of the World
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Biome- a large, relatively distinct terrestrial region with similar climate, soil,
plants, and animals, regardless of where it occurs in the world
Biomes around the World
Arctic Tundra- The treeless biome in the far north that consists of boggy
plains covered by lichens and small plants such as mosses; has harsh, very
cold winters, and extremely short summers (50-160 days)
o Occurs in the extreme northern latitudes
o Alpine Tundra-similar ecosystem located in the higher elevations of
mountains, above the tree line, and can occur in any latitude
o Tundra has a layer of permafrost, permanently frozen ground that
varies in depth and thickness. This limits root penetration depth
o Has a Low species richness (number of different species), and a low
primary productivity (rate at which energy is accumulated)
o Animals include lemings, voles, weasels, arctic foxes, snowshoe hares,
ptarmigan, snowy owls, and musk oxen
Boreal Forests-A region of coniferous forest in the northern hemisphere,
located just south of the tundra, but not in the southern hemisphere
o Winters are severe, but not as bad as tundra
o Permafrost is patchy, and where it is found, is often deep under the
soil
o Black and white spruces, balsam fir, eastern larch, and other conifers
dominate the boreal forest
o Animals include caribou, wolves, bears, and moose.
o Not suited to agriculture because of its short growing season and
mineral poor soil. However, the forest yields lumber and pulpwood
Temperate Rain Forest-a coniferous biome with cool weather, dense fog,
and high precipitation
o 50 in. of rain per year
o Trees include western hemlock, Douglas fir, western red cedar, Skita
spruce, and western arborvitae
o Squirrels, wood rats, mule deer, elk, bird species, sever amphibian
species and reptiles are common in temperate rain forest
o Temperate rain forest is a rich wood producer, giving lumber and
pulpwood
o Also one of the world’s most complex ecosystems in terms of species
richness
o Loggers replant the area after harvest with a monoculture (a single
species) of trees
Temperate Deciduous Forests-A forest biome that occurs in temperate
areas with a moderate amount of precipitation
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o Precipitation ranges from about 30-60 in. annually
o Soil is rich in organic material
o Trees form a dense canopy that overlies saplings and shrubs. These
include oak, hickory, maple, and beech
o Animals include deer, bears, and many small mammals and birds
o These were among the first biomes to be converted to agricultural use
Temperate Grasslands-a grassland with hot summers, cold winters, and
less rainfall than the temperate deciduous forest biome
o Precipitation averages about 10-30 in. annually
o Soil has considerable organic material
o Covered mostly with grass, although trees grow near rivers and
streams. Periodic wildfires help maintain grasses as the dominant
vegetation in grasslands
o Tallgrass Praries-moist temperate grasslands, occur in Midwest
 Originally covered with herds of grazing animals such as
pronghorn elk and bison
 Smaller animals included prairie dogs and foxes
o Shortgrass Prairies-temperate grasslands that receive less
precipitation. This occurs in Montana, South Dakota, and other
Midwestern states
 Grasses grow about knee high
Chaparral-a biome with mild, moist winters and hot, dry summers;
vegetation is typically small-leaved evergreen shrubs and small trees
o Have Mediterranean climates
o Vegetation looks strikingly similar all over the world
o Usually has a dense growth of evergreen shrubs but may contain
short, drought-resistant pine or scrub oak trees
o When a fire occurs, it doesn’t kill the underground parts of the plants,
and the spring back up in the winter
o Animals include mule deer, wood rats, chipmunks, lizards, and many
species of birds
Deserts-A biome in which the lack of precipitation limits plant growth;
deserts are found in both temperate and subtropical regions
o About 10 in. annually of precipitation
o Plants include cacti, yuccas, Joshua trees, and sage brushes
o Plants have adapted to need little water
o Animals tend to be small, and include frogs and toads, tortoises,
iguanas, Gila monsters, and Mojave rattlesnakes
o Mammals include gerbils, jerboas, and kangaroo rats. Also, mule deer,
jackrabbits, oryxes, and kangaroos
Savanna-a tropical grassland with widely scattered trees or clumps of trees
o Annual precipitation is 30-60 in.
o Soil is rich in aluminum, which resists leaching
o Animals include wildebeest, antelope, giraffe, zebra, elephants, lions,
hyenas
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o Savannas are rapidly being converted into rangeland for cattle
Tropical Rain Forest-a lush, species-rich forest biome that occurs where the
climate is warm and moist throughout the year
o Annual precipitation ranges from 80-180 in.
o Plants capture a lot of energy by photosynthesis. The trees are
typically evergreen flowering plants with shallow roots
o Rain forest has 3 layers of vegetation
 1) Topmost story consists of the crowns of occasional, very tall
trees who get direct sunlight
 2) Middle level forms a continuous canopy that lets in a little
sunlight to the lower level
 3) Smaller plants specialized for life in the shade occupy the
bottom level
o Most animals live in the trees, which include reptiles, amphibians,
insects, sloths, monkeys. There are large ground animals such as
elephants
Vertical Zonation
o The distribution of vegetation on mountains
o Base is covered by deciduous trees
o At higher elevations, there are coniferous subalpine forests
o The top of the mountain might have a permanent ice or snow cap
Aquatic Life Zones
o Plankton- small or microscopic organisms that are relatively feeble
swimmers
o Zooplankton-nonphotosynthetic organisms that include protozoa,
shrimplike crustaceans, and larval stages of many animals
o Nekton-larger strongly swimming organisms such as fishes, turtles and
whales
o Benthos-bottom dwelling organisms that fix themselves to one spot such
as sponges, or oysters
o Rivers and Streams
o Flowing Water Ecosystem-a freshwater ecosystem such as a
river or stream in which water flows in a current
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o Standing Water Ecosystems- A body of fresh water that is surrounded
by land and that does not flow
o Littoral Zone-a shallow-water area along the shore of a lake or
pond where light reaches the bottom
o Limnetic Zone- the open water beyond the littoral zone
o Profundal Zone-beneath the limnetic zone of a large lake
o Thermal Stratification-temperature of a lake changes sharply with
depth
o Turnover-Water shifts in order to spread O2 and nutrients
throughout the lake. It shifts between the limnetic and profundal
zone.
o Freshwater Wetland
o Land that shallow freshwater covers for at least part of the year
and that has a characteristic soil and water-tolerant vegetation
 On every continent except Antarctica
 Average of 7 in. of rainfall annually
 include marshes( grass like plants) and swamps ( woody
trees or shrubs)
 Animals include bird species, beaver, otters, muskrats,
game fishes, amphibians, alligators, turtles, snakes
o Estuaries-a coastal body of water, partly surrounded by land, with access
to the open ocean and a large supply of fresh water from a river
o Water levels rise and fall with the tide, while salinity fluctuates
with tidal cycles
o Greatly ranges in temperature seasonally and even daily.
Seasonal changes in the temperature
o Animals include oysters, shrimp and crabs, and worms
o Salt Marshes- shallow wetlands dominated by salt-tolerant
grasses
o Mangrove Forests- the tropical equivalent of salt marshes
Marine Ecosystems
o Intertidal Zone-the area of shoreline between low and high tides
o Benthic Environment-the ocean floor, which extends from the
intertidal zone to the deep ocean trenches (Photobenthic)
o Seagrass Beds- flowering plants adapted to complete
submersion in salty ocean water
o Kelp Forests- the largest brown algae
o Coral Reefs-built from accumulated layers of calcium
carbonate
 Fringing Reef-directly attached to the short of a volcanic
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Other Terms
island or continent and has no lagoon associated with it
Atoll-a circular coral reef that surrounds a central lagoon of
quiet water
o Pelagic Environment-consists of all ocean water
o Euphotic Zone- extends from the surface to a depth of
150m in the clearest ocean water
o Neritic Province-the part of the pelagic environment that
overlies the ocean floor from the shoreline to a depth of 200m
o Zooplankton-feed on phytoplankton in the euphotic zone
o Nekton- consume zooplankton, such as herring, sardines,
squid, manta rays
o Oceanic Province-The part of the pelagic environment that
overlies the ocean floor at depths greater than 200m
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Seagrass Beds- flowering plants adapted to complete submersion in salty
ocean water
Kelp Forests- the largest brown algae
Coral Reefs-built from accumulated layers of calcium carbonate, located in