2.4 Biomes
Assessment Statements
 2.4.1 Define the term biome
 2.4.2 Explain the distribution, structure, and relative
productivity of tropical rainforests, deserts, tundra,
and any other biome
2.4.1 Define the term biome
 A collection of
ecosystems sharing
similar climatic
conditions.
BIOME is the collection of ecosystems
sharing similar climatic conditions.
Cell 3 North
Cold,
dry air
falls
Model of global air
circulation and
biomes.
The direction of air
flow and the ascent
and descent of air
masses in
convection cells
determine the
earth’s climatic
zones.
Moist air rises — rain
Polar cap
Arctic tundra
Evergreen
coniferous forest
60°
Temperate deciduous
forest and grassland
Desert
30°
Cell 2 North
Cool, dry
air falls
Cell 1 North
Moist
air rises,
cools, and
releases
moisture
as rain
Tropical deciduous forest
0°
Equator
Tropical
rain forest
Tropical deciduous forest
30°
60°
Desert
Temperate deciduous
forest and grassland
Cell 1 South
Cool, dry
air falls
Cell 2 South
Polar cap
Cold,
dry air
falls
Moist air rises — rain
Cell 3 South
Uneven Solar Heating and Latitude
Earth as a whole is in thermal equilibrium, but different latitudes are not.
Moving masses of air and ocean currents transport energy from
locations with a surplus to those with a deficit.
2.4.2 Explain the distribution, structure, and relative productivity
of tropical rainforests, deserts, tundra, and any other biome
 Tropical Rainforest
 Temperature: 26 C
 Rainfall: Over 2500 mm/yr
 Insolation (Light Level):
High
 Distribution: Between the
tropics of cancer and
capricorn
 Structure: Highly stratified
(Emergent, Canopy,
Understory, Immature,
and Herb layers)
 Productivity: High
2.4.2 Explain the distribution, structure, and relative productivity
of tropical rainforests, deserts, tundra, and any other biome
 Desert
 Temperature: 45 C
 Rainfall: Under 250 mm/yr
 Insolation (Light Level):
High
 Distribution: 30 o N and S
 Structure: Little
vegetation, organisms
highly adapted to low
water and fluctuating
temperatures
 Productivity: Very low
2.4.2 Explain the distribution, structure, and relative productivity
of tropical rainforests, deserts, tundra, and any other biome
 Tundra
 Temperature: Low down to





-50 C
Rainfall: Low
Insolation (Light Level): Low
Distribution: High Latitudes
Structure: Plants with
leathery leaves or
underground storage organs,
larger animals with fur
Productivity: Low
2.4.2 Explain the distribution, structure, and relative productivity
of tropical rainforests, deserts, tundra, and any other biome
 Temperate forest
 Temperature: cold winters,





hot summers
Rainfall: 500-1500 mm/yr
Insolation (Light Level):
varies through year
Distribution: 40 to 60 o N
Structure: Dominated by one
species of tree (evergreen or
deciduous) bigger shrub layer
due to less dense canopy
Productivity: Relatively high
2.4.2 Explain the distribution, structure, and relative productivity
of tropical rainforests, deserts, tundra, and any other biome
 Grasslands
 Temperature: cold winters, hot





summers, fluctuate wildly if
removed from the sea
Rainfall: 250-500 mm/yr
Insolation (Light Level): varies
through year
Distribution: Almost every
continent 16% of the earth’s
surface
Structure: Diverse grasses, with
a mat of slowly decomposing
vegetation
Productivity: Relatively low
AQUATIC BIOMES
Ocean
Lakes
Coral reefs
Mangroves
Rivers
High tide
Low tide
Sun
Sea level
50
Euphotic Zone
100
Estuarine
Zone
Continental
shelf
Photosynthesis
0
500
Bathyal Zone
1,000
Twilight
200
1,500
Abyssal Zone
2,000
3,000
4,000
5,000
10,000
Darkness
Coastal Zone Open Sea
Depth in
meters
Aquatic Ecosystems
Environmental Factors
Temperature
Aquatic Ecosystems
Environmental Factors
Light
Aquatic Ecosystems
Environmental Factors
Salinity
The Black Sea
16 PPT
Baltic Sea
5-15 PPT
Lake Michigan 0.5 PPT
The Dead Sea
332 PPT
Pacific Ocean
36 PPT
The Red Sea & The Persian Gulf
40 PPT
Aquatic Ecosystems
Environmental Factors
Currents
Aquatic Ecosystems
Environmental Factors
Dissolved Oxygen
Dissolved Oxygen (mg/L)
Temperature
Temperature (ºC)
Depth (m)
Depth (m)
Dissolved
Oxygen
Aquatic Ecosystems
Zonation
Aquatic Ecosystems
Human Impacts
Waterways across the United States are
contaminated by a medicine chest of antibiotics,
hormones, caffeine, painkillers and other drugs
Agricultural runoff can carry fertilizers, including
traces of antibiotics and hormones, into waterways