Chapter 6 Major Ecosystems of the World

Overview of Chapter 6 o Earth’s Major Biomes Tundra, Boreal Forests, Temperate Rainforest, Temperate Deciduous Forests, Grasslands, Chaparral, Deserts, Savanna, & Tropical Rainforests Tundra, Boreal Forests, Temperate Rainforest, Temperate Deciduous Forests, Grasslands, Chaparral, Deserts, Savanna, & Tropical Rainforests Vertical Zonation Vertical Zonation o Aquatic Ecosystems Freshwater ecosystems Freshwater ecosystems Estuaries Estuaries o Marine Ecosystems o Interaction of Life Zones and Humans

Earth’s Major Biomes o Biome A large, relatively distinct terrestrial region with a similar climate soil, plants, and animals, regardless of where it occurs in the world A large, relatively distinct terrestrial region with a similar climate soil, plants, and animals, regardless of where it occurs in the world large, naturally occurring communities of plants and animals occupying a major habitat. large, naturally occurring communities of plants and animals occupying a major habitat. Nine major biomes Nine major biomes o Location is primarily determined by: Temperature (varies with latitude and elevation) Temperature (varies with latitude and elevation) Precipitation Precipitation o Biomes can also be defined by Winds, rapid temperature changes, fires, floods, etc. Winds, rapid temperature changes, fires, floods, etc.

Tundra o Treeless biome in the far north with harsh, cold winters and extremely short summers o Precipitation cm/yr cm/yr o Temperature Short growing season Short growing season days days

Tundra o Nutrient poor soils with little organic material Permafrost present Permafrost present o Low species richness Veg is mostly grasses and sedges Veg is mostly grasses and sedges Very simple food web Very simple food web o Low primary productivity

Tundra (Polar) Grasslands o Polar grasslands are covered with ice and snow except during a brief summer. Figure 5-17

Boreal Forests o A region of coniferous forests in the northern hemisphere Just south of tundra Just south of tundra o Covers 11% of earth’s land land o Growing Season A little longer than A little longer than tundra tundra o Precipitation ~ 50 cm/yr ~ 50 cm/yr

Boreal Forests o aka coniferous forest or taiga o Soils are acidic and mineral poor o Vegetation comprised of drought resistant conifers White spruce White spruce Balsam fir Balsam fir Eastern larch Eastern larch o Mostly small animals and migrating birds o Some large animals are present Wolves, bear, moose Wolves, bear, moose

Boreal Taiga Coniferous Forests o Consist mostly of cone-bearing evergreen trees that keep their needles year- round to help the trees survive long and cold winters.

Temperate Rainforest o Coniferous biome with cool weather, dense fog and high precipitation Ex: Northwest US Ex: Northwest US o Precipitation > 127 cm/yr > 127 cm/yr Heaviest in winter Heaviest in winter o Temperature Winters are mild Winters are mild Summers are cool Summers are cool

Temperate Rainforest o Soils are nutrient-poor, but high in organic material (dropped needles) Cool temperatures slow decomposition Cool temperatures slow decomposition o Dominant Vegetation Large evergreen trees Large evergreen trees Old-growth forest Old-growth forest (definition?) (definition?) o Variety of cool climate animal life climate animal life o Very high species richness richness o Heavily logged

Temperature Deciduous Forests o Forest biome that occurs in temperate areas with a moderate amount of precipitation o Precipitation cm/yr cm/yr o Temperature Seasonality Seasonality Hot summers and cold winters Hot summers and cold winters

Temperate Deciduous Forest o Topsoil is rich in organic material and underlain by clay o Vegetation is primarily deciduous (definition?) Oak, maple, beech Oak, maple, beech o Animals Deer, bear and small animals Deer, bear and small animals o Most of this biome land area has been regenerated after farming & timber harvest

Temperate Deciduous Forest o Most of the trees survive winter by dropping their leaves, which decay and produce a nutrient-rich soil. Figure 5-22

Grassland o Grasslands with hot summers, cold winters and too little precipitation to support trees o Precipitation cm/yr cm/yr o Tall grass prairies o Short grass prairies o 90% of this biome has been lost to farmland

Grassland o Soil has thick, organic material rich organic horizon o Periodic fires keep the dominant vegetation grasses vegetation grasses o Animals Once covered with bison- no longer true Once covered with bison- no longer true Smaller animals are still present (ex: prairie dogs) Smaller animals are still present (ex: prairie dogs)

Chaparral o Also called a Mediterranean Climate Ex: Southern California Ex: Southern California Ex: Greece Ex: Greece o Temperature Mild, moist winters Mild, moist winters Hot, dry summers Hot, dry summers o Frequent fires

Chaparral o Soil is thin and often not fertile o Vegetation Dense growth of evergreen shrubs Dense growth of evergreen shrubs Lush during the growing season Lush during the growing season o Animals Mule deer, chipmunks, many species of birds Mule deer, chipmunks, many species of birds

Deserts o Biome where lack of precipitation limits plant growth o Temperature Can very greatly in 24- hr period, as well as yearly (based on location) Can very greatly in 24- hr period, as well as yearly (based on location) o Precipitation < 25 cm/yr < 25 cm/yr

Deserts o Soils low in nutrients and high in salts o Vegetation sparse cactus and sagebrush cactus and sagebrush o Animals are very small to regulate temperature

Savanna o Tropical grassland with widely scattered trees o Temperature Varies little throughout the year Varies little throughout the year o Precipitation Seasons regulated by precipitation, not temperature Seasons regulated by precipitation, not temperature cm/yr cm/yr

Savanna o Soil low in nutrients due to leaching o Vegetation Wide expanses of grass Wide expanses of grass Occasional Acacia trees Occasional Acacia trees Have fire adaptive characteristics Have fire adaptive characteristics o Animals Herds of hoofed animals Herds of hoofed animals Large predators- lions, hyenas, etc. Large predators- lions, hyenas, etc.

Tropical Rainforest o Lush, species-rich biome that occurs where climate is warm and moist throughout the year o Precipitation cm/yr cm/yr o Very productive biome o Most species-rich biome

Tropical Rainforest o Ancient, weathered, nutrient-poor soil Nutrients tied up in vegetation, not soil Nutrients tied up in vegetation, not soil o Vegetation 3 distinct canopy layers 3 distinct canopy layers o Animals Most abundant insect, reptiles and amphibians on earth Most abundant insect, reptiles and amphibians on earth

Tropical Rain Forest o Tropical rain forests have heavy rainfall and a rich diversity of species. Found near the equator. Found near the equator. Have year-round uniformity warm temperatures and high humidity. Have year-round uniformity warm temperatures and high humidity. Figure 5-20

Distinguish between Altitude and Latitude o o Altitude and Latitude o o Altitude: distance above the earth’s surface o o Latitude: distance north or south of the equator o o How are they similar? o o Decrease temp with increased Altitude o o Decrease temp with increased Latitude

Vertical Zonation Increasing elevation has similar effect on ecosystem as traveling to higher latitudes