Biomes Chapter 21

Distribution of Life on Earth Influenced by weather (short term) and climate (long term weather patterns) Weather affects individuals; climate influences and limits the overall distribution of entire species

Weather & Climate are driven by the SUN Solar energy that reaches Earth drives the wind, ocean currents and global water cycle

Physical factors influence Climate Latitude- determines the angle at which the sun’s rays hit the earth- changes the temperature

Air Currents- generated by earths rotation cause large regions to be warm & dry, warm & wet, cold & dry or cold & wet

Ocean currents moderate near shore climates- coastal areas tend to have steadier temperatures because of the heat retained in the water

Continents & Mountains Irregularly shaped continents alter the flow of wind & water and contribute to the irregular distribution of biomes Mountains cause variation in altitude which affects temperature and modify rainfall patterns- rain shadows

Terrestrial Biomes Biomes are generally named after the dominant vegetation

Tropical Rain Forests On & around the equator Temp. b/w 77 F- 86 F RF- 100-160 inches Dominated by huge broad leaf evergreens Cover 6% of Earth’s surface Largest amount of biodiversity (2/3 of worlds total species) Soil is nutrient poor Colorful birds, frogs, monkeys, insects,

Grasslands/Savannas Center of continents 10-30 in. of annual rain Continuous cover of grass with almost no trees Hot dry summers tolerated by grasses kills trees Most fertile soil in the world Animals:North America-bison, prairie dogs, Africa-zebra, cheetah, lions

Deserts Less then 10 inches of rain/year Defined by lack of rain not heat Found on every continent Shallow rooted plants- areas of dirt surrounding them Dominant plants cacti & other succulents Might be hot during day and cold at night. Could be a cold desert (Asia) Animals-scorpions, mountain lion, snakes

Deciduous Forests 30-60 in. of rain Deciduous trees are the dominant species 4 distinct seasons Warm summer, cold winter 50 F- avg. temperature Oak, Beech, Maple, Deer, squirrels, fox, black bears, frogs, snakes, brown bears, rabbits

Taiga- Northern Coniferous Forest Winter long & cold- growing Season Short Dominated by needle bearing evergreen coniferous trees, spruce, douglas, pine Not many species live there- conditions too harsh Lynx, grizzly bear, moose, wolf, wolverine, snowshoe hare 30” of precipitation annually, 30-50 F, can be below freezing at night in the summer

Tundra Winter -40 F Winds avg. 30-60 mph 10 inches of rain or less annually Permafrost-permanently frozen ground Shallow root growth Flowers, moss, grasses, no trees caribou, mosquitoes, birds, wolves, snowy owls, artic foxes, grizzly bears, polar bears

Freshwater Covers less then 1% of the earths surface Rivers, streams, ponds, lakes & marshes Distribution of life depends of light, nutrients & access to the bottom Lakes have three life zones: Littoral- edge Limnetic- to the depth in which light penetrates the water Profundal- too deep for photosynthesis

Lakes classified by nutrient content Oligotrophic- low in nutrients