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Module 4:
Biomes of the World(Part-I)
Biomes are the the world's major communities, classified according to the predominant
vegetation and characterized by adaptations of organisms to that particular environment
(Campbell )
Biome is a large geographical region whose climate produces a characteristic climax
association of plants and animals
Major Biomes of the World
• Desert• Grassland• Forest• Tundra• Aquatic
– Freshwater– Marine
Distribution of major biomes of the world
Key points to understand a biome
• Climate• Distribution and geography• Special adaptations of vegetation• Types of animals found and their
adaptations
Desert Biome: Distribution
Desert Biome
1. Hot and Dry Deserts
2. Semi-arid Deserts
3. Coastal Deserts
4. Cold Deserts
• Covers one fifth of the land surface
• Rainfall is less than 50 cm per year
• Specialized vegetation and animals
• Soils have abundant nutrients, but little or no organic matter
• Disturbances are fairly common
Hot and Dry Deserts: Distribution
• North America: Chihuahua, Sonoran, Mojave and Great Basin; Southern Asia: Thar; Africa: Sahara, and Australia
Hot and Dry Deserts
• Climate is warm throughout the year and very hot during summers
• Evaporation rates exceeds rainfall• Soils are course-textured, shallow, rocky or gravely
with good drainage; no subsurface water• Flora: Cactus, ocotillo, turpentine bush, prickly pears, false mesquite, sotol, ephedras, agaves and brittlebush• Fauna: Small nocturnal carnivores, insects, reptiles, birds
Sonoran desert
http://mwsu-bio101.ning.com/forum/topics/a-sonoran-desert-community
Thorny devil
Moloch horridus
Hot and Dry Deserts: Animals
http://biology.ucr.edu/people/faculty/Garland.html
Kangaroo-rat
Dipodomys spectabilis
Hot and Dry Deserts: Animals
Semi arid Deserts
• Montana and Great Basin; North America, Newfoundland, Greenland, Russia, Europe and northern Asia.
• Summers are moderately long and dry• Soil ranges from sandy to fine textured
Semi arid Deserts
• Flora:Creosote bush, bur sage (Franseria deltoidea), Acacia constricta, cat claw cactus, Prosopis spp., brittle bushes (Encelia farinosa), Zizyphus spp.
• Fauna:Rabbits; insects like grasshoppers and ants; lizards and snakes; burrowing owls and the California thrasher
Semi arid Deserts
Coastal deserts• Occur in moderately cool to warm
areas• Soil is fine-textured with a moderate
salt content; fairly porous with good drainage
Coastal Desert
• Flora:
salt bush, buckwheat bush, black bush, rice grass, little leaf horsebrush, black sage, and Euphorbia spp.• Fauna:
spoonbill, sandpiper, coyote and badger, toads, great horned owl, golden eagle and the bald eagle, lizards and snakes
Coastal Desert: Fauna
spoonbill
Dorcas gazelle
Fennec fox
Cold Deserts• Cold winters with snowfall less than 10
inches; short, moist and moderately warm summers
• Soil is heavy, silty and salty
Cold Deserts
• Flora:
Bunchgrass, Artemisia spp.(sagebrush), Chrysothamnus spp. (rabbit bush)
• Fauna:
Proghorn antelope, bighorn sheep, marco polo sheep, mountain lion
Basin wildrye
Marco polo sheep
Proghorn antelope
Grassland Biome: Distribution• Large terrains of grasses, herbs and grasses
• Average annual precipitation is enough to support grasses; erratic..drought and fires prevent growing of trees
• Soil is thin and dry
Steppes
• Dry, cold grassland• Found in USA, Mongolia, Siberia, Tibet
and China • Found between forest and desert biome• Grasses dominate
Steppes
Steppes: vegetation
Tumble weed
Salsola collina
Fringed sagebrush
Artimisia frigida
Rhubarb
Rheum rhabarbarum
Steppes : Fauna
Saiga antelope
Saiga tatarica
Northern Lynx
Felis lynx
Prairies: Distribution
• Found in North America• Dominated by herbaceous plants and
grasses
Turkey feet grass
Andropogon gerardii
Indian grass
Sorghastrum nutans
Milkweed
Asclepias currasavica
Prairies: Vegetation
American bald eagle
Haliaeetus leucophalusPrairie dog
Cynomis ludovicianus
Prairies: Fauna
Pampas: Distribution
• Found in South America• Flat, fertile plains; warm, humid climate• Frequent fires
Silver pampas grass
Cortaderia selloana
Pampas: vegetation
Geofrroy’s cat
Oncifelis geoffroyi
Ombu
Phytolacca dioica
Savanna
• Also known as tropical grasslands• Warm temperature year around with a
very long dry winter,and a lots of rain in the summer
savanna
Savanna: Flora and Fauna
• Flora:
• Cynodon dactylon, Pennesetum perpureum (napier grass/ elephant grass), Eucalyptus cinerea, Acacia tortilis, Acacia senegal
• Fauna:
• Elephant, buffaloes, antelopes, rhino, Giraffe, Wild Dog, Black Mamba, Caracal, Chacma Baboon, Egyptian Mongoose, Emu, Grant's Zebra, Koala Bear, Lion, leopard, cheetah, Nigriceps Ants, Nile Crocodile
Savanna: vegetation
Euphorbia ingens
Acacia tortilis
Savanna: Fauna
Black mamba
savanna baboons
Egyptian mongoose
Emu
Forest Biome
1. Tropical forests
2. Deciduous forests
3. Alpine forests
4. Boreal forests OR Taiga
Tropical forest: Distribution
Tropical Forest Biome
• Occur near the equator
• Cover around 6% of the earth’s surface• Distinct seasonality: winter is absent, and
only two seasons are present (rainy and dry). • Temperature and water are not limiting• Soil is nutrient-poor and acidic.
Decomposition is rapid and soils are subject to heavy leaching
• Greatest diversity of species
Tropical Forest Biome
• Canopy is multilayered and continuous, allowing little light penetration
• Vegetation: mostly evergreen, with large dark green
leaves. Plants such as orchids, bromeliads, vines (lianas), ferns, mosses, and palms are present
• Fauna:numerous birds, bats, small mammals, and insects
Tropical forest: vegetation
Bambusa tulda Ceiba pentandra Ficus spp.
Golden toadspider
Tropical forest: Fauna
Temperate deciduous Forest Biome
• Occur in eastern North America, northeastern Asia, and western and central Europe
• Well-defined seasons with a distinct winter
• Moderate climate and a growing season of 140-200 days during 4-6 frost-free months
Temperate deciduous Forest Biome• Temperature varies from -
30° C to 30° C• Precipitation (75-150 cm)
is distributed evenly throughout the year
• Soil is fertile, enriched with decaying litter
Temperate deciduous Forest Biome
• Flora:Broad leaved deciduous plants-oak, hickory, pine, beech, hemlock, maple, basswood, cottonwood, elm, willow, and spring-flowering herbs
• Fauna:squirrels, rabbits,
skunks, birds, deer, mountain lion, bobcat, timber wolf, fox, and black bear.
Alpine Forests: Distribution
• Himalayan mountains• Andes mountains…South America• Rocky mountains…western North America
Alpine: Climate
• Found in the high mountains all over the world usually above 10,000 ft.
• Cold and dry throughout the year• Soil is well drained• Vegetation:
Alpine Phaceli, Bear Grass, Bristle cone Pine, Moss Campion, Polylepis Forest, Pygmy Bitterroot, Wild Potato
• Fauna: mountain goat, snow leopard, Yak, Himalayan tahr, takin, marmot etc.
• Dry air, low precipitation• Harsh environment with long cold
winters, mild short summers
Himalayan Alpine: Distribution and climate
Himalayan Alpine: VegetationRhododendron spp.
Himalayan Alpine: Fauna
Himalayan tahr
Hemitragus spp.
Snow leopard
Panthera uncia
Yak
Bos grunniens
Himalayan Alpine: Fauna
Takin Budorcas taxicolor
Marmot
Marmota himalayana
Taiga biome: Distribution
Boreal forests/ Taiga biome
• Largest terrestrial biome, covers 11% area • Broad belt of Eurasia and North America: two-
thirds in Siberia with the rest in Scandinavia, Alaska, and Canada
• short, moist, and moderately warm summers and long, cold, and dry winters
• The length of the growing season is 130 days• Precipitation is primarily in the form of snow,
40-100 cm annually.
Boreal forests/ taiga
• Soil is thin, nutrient-poor, and acidic
• Canopy permits low light penetration, and as a result, under story is limited.
• Flora :Evergreen conifers with needle-like leaves: Balsam Fir, Black Spruce, Douglas-fir, Eastern Red Cedar, Jack Pine, Paper Birch, Siberian Spruce, White Fir, White Poplar, White Spruce
• Fauna: American Black Bear, Bald Eagle, Bobcat, Canadian Lynx, Gray Wolf, Grizzly Bear, Long-Eared Owl, Red Fox, River Otter, Snowshoe Rabbit, Wolverine
Taiga Biome: vegetation
Balsam fir Abies balsamea Jack pine Pinus banksiana
Taiga Biome: vegetationWhite Birch Betula populifolia White popular Populus alba
Taiga Biome: vegetationDouglas fir Pseudotsuga menziesii
White spruce Picea glauca
Taiga Biome: Fauna
American Black bear Ursus americanus Bald eagle
Haliaeetus leucocephalus
Snow shoe rabbitLepus americanus
Tundra biome: Distribution• Tundra Finnish word ‘tunturia’ barren land• Bleak and treeless place• World’s youngest, coldest and driest biome..formed
10,000 years ago• Covers 20% of the Earth’s surface..Northern
hemisphere
Tundra biome: Climate
• The ground is permanently frozen 10 inches to 3 feet
• Main seasons: Winter..summer• Average annual temperature -280C [ max –700C; max 120C]
• Land of midnight sun• Strong winds; 6-10 inches of precipitation each year
• One of the major sinks of carbon
Tundra biome: Lichens
Tundra biome: vegetation
Arctic willowSalix arctica
• Adaptations: low growing plant; fine silky hair, leathery leaves
Arctic mossCalliergon giganteum
Bear berry
Arctostaphylos uva-ursi
Tundra biome: animals
Arctic foxLagopus alopex
Caribou / ReindeerRangifer tarandus
References
• Campbell, N.A. 1996. Biology, 4th Edition. The Benjamin/Cummings Publishing Company, Inc., Menlo Park, California.
• http://www.ucmp.berkeley.edu/exhibits/biomes/marine.php
• http://earthobservatory.nasa.gov/Experiments/Biome/Images/pictemperate.jpg