KEY CONCEPT Biomes are land-based, global communities of organisms.

Earth has several major biomes. A biome is a major community of organisms.

Tropical rain forest biomes produce lush forests. Source: World Meteorological Organization Tropical rain forest biomes produce lush forests. warm temperature abundant precipitation all year

Grassland biomes are where the primary plant life is grass. Rapid City, South Dakota Source: National Oceanic Atmospheric Administration

Grassland biomes are where the primary plant life is grass. Temperate grasslands are dry and warm during the summer; most precipitation falls as snow. Tropical grasslands are warm through the year, with definite dry and rainy seasons.

Desert biomes are characterized by a very arid climate. Tucson, Arizona Source: National Oceanic Atmospheric Administration very low amount of precipitation four types: hot, semi-arid, coastal, and cold

Temperate forest biomes include deciduous forests and rain forests. Temperate deciduous forests have hot summers and cold winters. Deciduous trees are the dominant plant species. Source: National Oceanic Atmospheric Administration Burlington, Vermont

Temperate forest biomes include deciduous forests and rain forests. Temperate deciduous forests have hot summers and cold winters. Deciduous trees are the dominant plant species. The temperate rain forests have a long wet season and relatively dry summer. Ferns and moss cover the forest floor. 

The taiga biome is located in cooler northern climates. Source: Environment Canada Banff, Canada boreal forest long winters and short summers small amount of precipitation

limited precipitation permafrost Barrow, Alaska Source: National Oceanic Atmospheric Administration The tundra biome is found in the far northern latitudes with long winters. winter lasts 10 months limited precipitation permafrost

Minor biomes, such as chaparral, occur globally on a smaller scale.

Polar ice caps and mountains are not considered biomes. Polar ice caps have no soil, therefore no plant community. The climate and organisms found on mountains change as the elevation changes.

KEY CONCEPT Marine ecosystems are global.

The ocean can be divided into zones. Ocean zones can be determined by their distance from shoreline and water depths. intertidal zone—between low and high tide neritic zone—from intertidal zone to continental shelf bathyal zone—from neritic zone to base of continental shelf abyssal zone –lies below 2000 m intertidal zone neritic zone bathmat zone abyssal zone

The neritic zone harbors more biomass than any other zone. Plankton make up most of the biomass. zooplankton phytoplankton

Coastal waters contain unique habitats. Coral reefs are found in warm waters. tropical climate zone great amount of biomass

Kelp forests are found in cold, nutrient-rich waters. large communities of seaweed great amount of biomass

KEY CONCEPT Freshwater ecosystems include estuaries as well as flowing and standing water.

Estuaries are dynamic environments where rivers flow into the ocean. An estuary is a partially enclosed body of water. mixture of fresh water with salt water Chesapeake Bay Louisiana bayous

Estuaries are highly productive ecosystems. Estuaries provide a protected refuge for many species. birds migration spawning grounds Estuaries are primarily threatened by land development.

Freshwater ecosystems include moving and standing water. A watershed is a region of land that drains into a body of water. Ecosystems may be different along a river’s course

Wetlands are among the most productive ecosystems. provide a home for many species filter dirty water renew underground water supply Some animals have adaptations suited to the freshwater they inhabit.

Ponds and lakes share common features. Freshwater bodies are divided into three zones. littoral zone limnetic zone benthic zone

All lakes “turn over” periodically. Turn over happens due to changes in density. In both autumn and spring, surface water flows downward and bottom water flows upward. The upwelling brings up nutrients.