2.4.1-.2 Biomes
BIOME is the collection of ecosystems sharing similar climatic conditions.
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.
Cell 3 South
Cold,dry air falls
Moist air rises — rain
Cell 2 South
Cool, dryair falls
Cell 1 South
Moistair rises,cools, andreleasesmoistureas rain
Cell 1 North
Cool, dryair falls
Cell 2 North
Moist air rises — rain
Cell 3 NorthCold,dry airfalls
Polar capArctic tundra
60°
30°
0°
30°
60°
Polar cap
Evergreenconiferous forest
Temperate deciduousforest and grassland
Desert
Tropical deciduous forest
Equator Tropical rain forest
Tropical deciduous forest
DesertTemperate deciduousforest and grassland
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.
MountainIce and snow
Altitude
Tundra (herbs,lichens, mosses)ConiferousForest
Tropical Forest
DeciduousForest
Tropical Forest
DeciduousForest
ConiferousForest
Tundra (herbs,lichens, mosses)
Polar iceand snow
Latitude
Generalized effects of altitude and latitude on climate and biomes.Parallel changes in vegetation occur when moving from the Equator to the poles or from the lowlands to mountaintops.
DESERT BIOMES
Tropical desert(Saudi Arabia)
Polar desert(northwest China)
GRASSLAND BIOMES
Tropical grassland (savanna)(Harare, Zimbabwe)
Polar grassland (arctic tundra)(Fort Yukon, Alaska)
FOREST BIOMES
Tropical rain forest(Manaus, Brazil) Temperate deciduous forest
(Nashville, Tennessee)
AQUATIC BIOMES
Coral reefsRivers
Lakes MangrovesOcean
High tideLow tide
Coastal Zone
EstuarineZone
Continentalshelf
Open SeaSea level
Sun
Euphotic Zone
Bathyal Zone
Abyssal Zone
Depth inmeters
0
50
100
200 Phot
osyn
thes
is
500
1,000
1,500
2,000
3,000
4,000
5,000
10,000
Dar
knes
sTw
iligh
t
DIVERSITY is a generic term for heterogeneity. If may refer to:
1. Genetic diversity is the total number of genetic characteristics of a specific species.
2. Habitat diversity is the diversity of habitats in a given unit area.
3. Species diversitya. Species richness – total number of species.b. Species evenness – relative abundance of
each species.c. Species dominance – the most abundant
species.
Figure a and b have the same species
richness, but different
species evenness.
Changes in the distribution of animals with elevation on a typical mountain in Kenya.
Change in the relative abundance of a species over an area or a distance is referred to as an
ecological gradient.