Chapter 6 Biomes
Biome • Large region characterized by a specific type of climate and certain types of plants and animal communities • Each biome is made up of many individual ecosystems
Biomes are described by their vegetation because plants that grow in an area determine the other organisms that live there. • Plants have specialized structures or adaptations that allow them to survive in a particular biome. • Ex: 1. Desert plants like cactus- large cuticle, no • leaves • 2. Tundra plants are short from lack of water
Climate • Main factor in determining what plants can grow in a particular area. • Climate refers to temp, precipitation, humidity, and wind in an area over a long period of time.
Biomes also vary with latitude and altitude • Latitude- the distance north or south of the equator and it is measured in degrees • Altitude- the height of an object above sea level • Climate gets colder as latitude and altitude increase
The temperate region of the world, between 30 and 60 degrees north latitude and 30 and 60 degrees south latitude is where most of the food in the world is grown.
Forest Biomes • most widespread and most diverse biomes • Forests exist where temps are mild to hot and rainfall is plentiful • 3 main types of forest biomes
1. Tropical Rain Forest • located in a belt around the Earth near the equator • help regulate world climate • Play a vital role in the N, O, and C cycles • Enormous amount of biodiversity, only 7% of the land but 50% of all plant and animal species
Tropical Rain Forest • Always humid and warm • Get about 200 to 450 cm of rain a year • Get sunlight year round • Very poor soil, nutrients locked up in plants • Runoff from Rainforests is often as pure as distilled water
Layers of the Rain Forest • 1. Emergent layer- consists of the tallest trees 60-70 m in height. • Trees in this layer grow and emerge in direct sunlight. Eagles, monkeys, bats and snakes live here. • 2. Upper Canopy layer- Trees growing up to 30 m tall. Forms a dense layer that absorbs up to 95 % of the sunlight.
Layers of the Rain Forest • 3. Lower Canopy layer- receives less light than the upper canopy. • Epiphytes live here. They live off of other trees. • Orchids and mistletoe are examples. • Most animals that live in the rainforest live in the upper and lower canopy. • 4. Understory- Found underneath the canopy. Very little light reaches here. • Plants here grow only up to 3.5 m tall. Many have large flat leaves.
Threats to the Rain Forests • We lose 100 acres of rain forest every minute of every day to: • • Logging • • Agriculture • • Oil exploration • • Exotic pet trading
2. Temperate Rain Forests • • Occurs in North America, Australia, and New Zealand • • Large amounts of precipitation, high humidity and moderate temps • • Trees are covered in mosses • • Forest floor is covered in ferns • • Sitka spruce and Douglas fir can reach 90m tall (270ft)
Douglas Fir Sitka Spruce
3. Temperate Deciduous Forest • • Located between 30 degrees and 50 degrees north latitude • • Trees have broad flat leaves that they drop each fall • • Winter temperatures often drop below freezing, meaning little water for plants • • Receives 75-125 cm of precipitation annually
Temperate Deciduous Forest • • Rich deep soils due to fallen leaves • • Tall trees like oak, maple, birch are the top layer with smaller trees and shrubs covering the understory • • More light reaches the forest floor than in rain forests so more mosses, ferns and herbs grow here
4. Taiga- AKA- Boreal Forest AKA- Northern Coniferous Forest • • Found in the northern hemisphere just below the Arctic circle • • Winters are long (6-10 months) with temps below freezing • • Growing season in summer may be as short as 50 days • • Forest floor has few plants because of the acidic pine needles • • Soil forms slowly because decomposition is slow
Tropical Grasslands • • Called Savannas • • Located in tropical and subtropical areas near the equator and between tropical rainforests and desert biomes • • Contain grasses, scattered trees and shrubs • • Large variety of grazing animals and predators • • Receive little precipitation
Tropical Grasslands • • Have a wet and a dry season • • Grass fires sweep through and return nutrients to the soil • • Plants have large horizontal root systems to help obtain water during the dry season • • Some trees lose their leaves to help retain water • • Animals include: elephants, gazelles, rhinos, giraffes all of which are different heights to reduce competition
Temperate Grasslands • • Dominated by grasses and has very few trees • • Only receive a moderate amount of rainfall (50-88 cm a year) • • Most fertile soil of any biome • • Many have been replaced with crops, farms and grazing land
Temperate Grasslands • • Few natural grasslands remain • • Found in the interior of continents where there is too little rain for trees • • Found in North American, Russian steppes, and in South America
3 types of temperate grassland • *(determined by the rainfall and vegetation that grows there) • 1. Short grass prairie (about 25 cm rain per year) • 2. Mixed or middle grass prairie (about 50 cm rain per year) • 3. Tall grass prairie ( up to 88 cm rain per year)
Short Grass Prairie Mixed Grass Prairie Big Blue Stem Grass 6 ft tall Tall Grass Prairie
Animals • • Pronghorn • • Bison, • • Badgers • • Prairie dogs • • Owls and hawks
Chaparral • • Temperate woodland biome • • Dominated by broad-leafed evergreen shrubs than by evergreen trees • • Located primarily in coastal areas that have Mediterranean climates (30 degrees North or South of Equator) • • Common plants- scrub oak, olive trees, sage, manzanita
Chaparral • • Most leaves have oils that promote burning • • Most plants here can resprout from small bits of surviving plant tissue • • Animals include- quail, lizards, chipmunks and mule deer • • The greatest threat to this biome is human development, because they are near the ocean and have a mild climate
Deserts • • Driest places on Earth • • Less than 25 cm rain a year • • Little to no vegetation • • Plants found there are called succulents • • Some animals like toads survive the summers by estivating • • Most animals are also nocturnal
Tundra • • Located primarily north of the arctic circle • • Most precipitation remains frozen most of the year • • Soil supports tough grasses and shrubs • • Mosses and lichens are common • • Plants have wide shallow root because of the permafrost • • Animals include migratory birds that go their to breed, caribou, wolves, musk ox, deer, moose
Tundra • • Tundra is one of the most fragile biomes • o Food chains are simple and easily disrupted • o Land is easily damage and slow to recover • o Oil exploration