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Biomes
• Definition: a major geographic region defined on the
basis of dominant plant growth forms.
• Determinants: 1) Climate- particularly temperature
and rainfall patterns; 2) Topography (landforms) and
soils (edaphic factors): factors that secondarily
influence the local distribution of organisms within
biomes.
• Climatic zones: 1) boreal (mean <5ºC), 2) temperate
(mean >5, <20 ºC), 3) tropical (mean >20ºC).
• The biome concept applies best to terrestrial systems.
Grouping
Characteristics
• Plants and animals from
different parts of the world
often show similar
characteristics if they are part
of the same biome (character
convergence).
• The catbird (upper right) of
North America and the reedwarbler (lower right) of
southeast Asia are ecologically
equivalent species.
• They also show similar
physiological adaptations.
• Plants further show similar
growth forms.
Principal
Biomes
Tundra:
1)
2)
3)
4)
5)
Climate- polar
Vegetation- treeless, low
evergreen shrubs, herbs and
lichens
Limiting factor- permafrost
Distribution- far northern
hemisphere and alpine
zones
Animals- polar bear (right)
Principal
Biomes
Boreal Forest (Taiga):
1)
2)
3)
4)
5)
Climate- cool summer,
long, cold winter
Vegetation- evergreen and
deciduous conifers
Limiting factor- short
growing season (10 weeks)
Distribution- northern
hemisphere and alpine
zones
Animals- blue-headed
vireo (right).
Principal
Biomes
Temperate Grassland (Prairie):
1)
2)
3)
4)
5)
Climate- hot summer, cold winter
(continental climate)
Vegetation- grasses and forbs; trees along
rivers (riparian forest)
Limiting factor- annual rainfall about 10”
Distribution- centers of continents
Animals- bison (above), prairie dog (left)
Principal
Biomes
Temperate Seasonal Forest:
1)
2)
3)
4)
5)
Climate- moderate; winter
mean >-20ºF
Vegetation- deciduous trees
Limiting factor- 17 week
growing season
Distribution- eastern North
America, western Europe,
Korea
Animals- red-spotted newt
(right)
Principal Biomes
Temperate Rainforest:
1)
2)
3)
4)
5)
Climate- mild and wet
Vegetation- large conifers
Limiting factor- summer rain
and fog
Distribution- Pacific northwest,
New Zealand, S. South America
Animals- ruby-crowned kinglet
Principal
Biomes
Shrubland (Chaparral):
1)
2)
3)
4)
5)
Climate- summer drought, rainy winter
Vegetation- waxy-leaved, evergreen shrubs
Limiting factor- frequent fires
Distribution- S. California, Mediterranean,
S. Australia
Animals- western tanager (left)
Principal
Biomes
Subtropical Desert:
1)
2)
3)
4)
5)
Climate- very dry, high daytime
temperature
Vegetation- sparse, with drought-resistant
leaves
Limiting factor- heat, dryness
Distribution- southwestern North America,
central Africa, central Asia
Animals- spadefoot toad (left)
Principal
Biomes
Tropical Savannah:
1)
2)
3)
4)
5)
Climate- rainy summer, dry winter
Vegetation- grasslands with park-like
stands of trees
Limiting factor- limited rainfall
Distribution- Mexico, S. Africa, SE Asia,
N. Australia, E. S. America
Animals- burrowing owl (right)
Principal
Biomes
Tropical Rainforest:
1)
2)
3)
4)
5)
Climate- uniform hot, wet
and dry seasons
Vegetation- diverse
tropical hardwoods and
vines
Limiting factor- heavy
rainfall and uniform high
temperatures
Distribution- N. S.
America, W. Africa, SE
Asia
Animals- fruit dove (right)
Alpine Zonation
• Increasing altitude mimics the
effects of increasing latitude.
• At higher altitudes in
mountains, more northerly
associated biomes are found.
• In the northeast, the lowest
elevations of mountains have
temperate seasonal forest,
which is replaced by boreal
forest at higher elevations,
which is in turn replaced by
alpine tundra.
• Near tree line (the highest
elevation of tree growth), a
stunted boreal forest called
krummholz develops.
• Alpine biomes differ from
latitudinal biomes in factors
like day length and
temperature variation.
Global Biome Distribution
Climatic Relationship of Biomes