Biomes

Learning Objectives Describe what biotic and abiotic factors characterize

biomes. Identify the areas that are not classified into a major

biome.

Regional Climates

Upwind side Downwind side

Air rises and cools, releasing moisture.

Air descends, warms, and becomes drier, decreasing moisture.

Earth’s Biomes

Reading a Climate Diagram

Tropical Rain Forest

Abiotic: warm and wet year-round; soils are thin and nutrient-poor

Abiotic: warm and wet year-round; soils are thin and nutrient-poor

Biotic: plants with large leaves and buttress tree roots; animals active year-round

Biotic: plants with large leaves and buttress tree roots; animals active year-round

Tropical Dry Forest

Rainy season

Abiotic: warm year-round; alternating wet-dry seasons; rich soils

Abiotic: warm year-round; alternating wet-dry seasons; rich soils

Biotic: deciduous plants, waxy plant leaves; many animals estivate or migrate

Biotic: deciduous plants, waxy plant leaves; many animals estivate or migrate

Tropical Grassland/Savanna/Scrubland

Biotic: plants with waxy leaves, seasonal leaf loss; many animals migrate or are dormant during dry season

Biotic: plants with waxy leaves, seasonal leaf loss; many animals migrate or are dormant during dry season

Abiotic: warm; seasonal rainfall; compact soils; frequent fires set by lightning

Abiotic: warm; seasonal rainfall; compact soils; frequent fires set by lightning

Desert

Precipitation, not temperature, defines deserts.

Biotic: small plant leaves; many animals nocturnal, many get water from their food

Biotic: small plant leaves; many animals nocturnal, many get water from their food

Abiotic: low precipitation; variable temperatures; soils poor in organic material

Abiotic: low precipitation; variable temperatures; soils poor in organic material

Temperate Grassland

Biotic: plants resistant to grazing and fire; small animals use camouflage and burrowing as protection

Biotic: plants resistant to grazing and fire; small animals use camouflage and burrowing as protection

Abiotic: warm summers, cold winters; moderate precipitation; fertile soils; occasional fires

Abiotic: warm summers, cold winters; moderate precipitation; fertile soils; occasional fires

Temperate Woodland and Shrubland

High threat of wildfire

Biotic: plants adapted to drought and fire; animals commonly browsers

Biotic: plants adapted to drought and fire; animals commonly browsers

Abiotic: warm, dry summers; cool, moist winters; nutrient-poor soils; periodic fires

Abiotic: warm, dry summers; cool, moist winters; nutrient-poor soils; periodic fires

Temperate Forest

Biotic: deciduous trees; some animals hibernate, some migrate in winter

Biotic: deciduous trees; some animals hibernate, some migrate in winter

Abiotic: cold winters, warm summers; year-round precipitation; fertile soils

Abiotic: cold winters, warm summers; year-round precipitation; fertile soils

Northwestern Coniferous Forest

Biotic: dense plant growth, tall trees; many animals have varied diets

Biotic: dense plant growth, tall trees; many animals have varied diets

Abiotic: mild temperatures; abundant precipitation in fall, winter, and spring; cool, dry summers; rocky, acidic soils

Abiotic: mild temperatures; abundant precipitation in fall, winter, and spring; cool, dry summers; rocky, acidic soils

Boreal Forest

Biotic: dark-green conifers; many animals have extra insulation, some migrate in winter

Biotic: dark-green conifers; many animals have extra insulation, some migrate in winter

Abiotic: long, cold winters; mild summers; moderate precipitation; acidic, nutrient-poor soils

Abiotic: long, cold winters; mild summers; moderate precipitation; acidic, nutrient-poor soils

Tundra

Low precipitation

Biotic: small plants growing low to the ground; many animals migrate in winter or have heat-saving adaptations

Biotic: small plants growing low to the ground; many animals migrate in winter or have heat-saving adaptations

Abiotic: strong winds; low precipitation; short, soggy summers; long, cold, dark winters; permafrost

Abiotic: strong winds; low precipitation; short, soggy summers; long, cold, dark winters; permafrost

Other Land Areas

Mountain ranges and polar ice caps are not easily defined by typical plant and animal communities.

Overview: Biomes