Biomes Definition: a major geographic region defined on the basis of dominant plant growth...
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Transcript of Biomes Definition: a major geographic region defined on the basis of dominant plant growth...
Biomes
• Definition: a major geographic region defined on the Definition: a major geographic region defined on the basis of dominant plant growth forms.basis of dominant plant growth forms.
• Determinants: 1) Climate- particularly temperature Determinants: 1) Climate- particularly temperature and rainfall patterns; 2) Topography (landforms) and and rainfall patterns; 2) Topography (landforms) and soils (edaphic factors): factors that secondarily soils (edaphic factors): factors that secondarily influence the local distribution of organisms within influence the local distribution of organisms within biomes.biomes.
• Climatic zones: 1) boreal (mean <5ºC), 2) temperate Climatic zones: 1) boreal (mean <5ºC), 2) temperate (mean >5, <20 ºC), 3) tropical (mean >20ºC).(mean >5, <20 ºC), 3) tropical (mean >20ºC).
• The biome concept applies best to terrestrial systems.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 reed-warbler (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) Climate- polar
2) Vegetation- treeless, low evergreen shrubs, herbs and lichens
3) Limiting factor- permafrost
4) Distribution- far northern hemisphere and alpine zones
5) Animals- polar bear (right)
Principal Biomes
Boreal Forest (Taiga):1) Climate- cool summer,
long, cold winter
2) Vegetation- evergreen and deciduous conifers
3) Limiting factor- short growing season (10 weeks)
4) Distribution- northern hemisphere and alpine zones
5) Animals- blue-headed vireo (right).
Principal Biomes
Temperate Grassland (Prairie):1) Climate- hot summer, cold winter
(continental climate)
2) Vegetation- grasses and forbs; trees along rivers (riparian forest)
3) Limiting factor- annual rainfall about 10”
4) Distribution- centers of continents
5) Animals- bison (above), prairie dog (left)
Principal Biomes
Temperate Seasonal Forest:1) Climate- moderate; winter
mean >-20ºF
2) Vegetation- deciduous trees
3) Limiting factor- 17 week growing season
4) Distribution- eastern North America, western Europe, Korea
5) Animals- red-spotted newt (right)
Principal BiomesTemperate Rainforest:1) Climate- mild and wet
2) Vegetation- large conifers
3) Limiting factor- summer rain and fog
4) Distribution- Pacific northwest, New Zealand, S. South America
5) Animals- ruby-crowned kinglet
Principal Biomes
Shrubland (Chaparral):1) Climate- summer drought, rainy winter
2) Vegetation- waxy-leaved, evergreen shrubs
3) Limiting factor- frequent fires
4) Distribution- S. California, Mediterranean, S. Australia
5) Animals- western tanager (left)
Principal Biomes
Subtropical Desert:1) Climate- very dry, high daytime
temperature
2) Vegetation- sparse, with drought-resistant leaves
3) Limiting factor- heat, dryness
4) Distribution- southwestern North America, central Africa, central Asia
5) Animals- spadefoot toad (left)
Principal Biomes
Tropical Savannah:1) Climate- rainy summer, dry winter
2) Vegetation- grasslands with park-like stands of trees
3) Limiting factor- limited rainfall
4) Distribution- Mexico, S. Africa, SE Asia, N. Australia, E. S. America
5) Animals- burrowing owl (right)
Principal Biomes
Tropical Rainforest:1) Climate- uniform hot, wet
and dry seasons
2) Vegetation- diverse tropical hardwoods and vines
3) Limiting factor- heavy rainfall and uniform high temperatures
4) Distribution- N. S. America, W. Africa, SE Asia
5) 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