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Chapter 6 Climate, Biomes, and Terrestrial Biodiversity What is weather? ► ► Short-term properties of the troposphere Troposphere: inner layer of the atmosphere (most of the Earth’s air) Temperature Pressure Humidity Precipitation Sunshine Cloud cover Warm Fronts ► Warm air meets and rises up over a retreating mass of more dense cool air Cold Fronts ► Cold air moves under a mass of less dense warm air Weather Extremes ► ► Tornadoes (form over land) - funnel-shaped clouds (vortexes) - US is most tornado-prone country Tropical cyclones (form over warm ocean waters) - Hurricane (forms in Atlantic Ocean) - Typhoon (forms in Pacific Ocean) Figure 6-3 Page 112 Descending cool air Severe thunderstorm Tornado forms when cool downdraft and warm updraft of air meet and interact Rising warm air Severe thunderstorms can trigger a number of smaller tornadoes Rising updraft of air Figure 6-4 Page 113 Rising winds exit from the storm at high altitudes. The calm central eye usually is about 24 kilometers (15 miles) wide. . Moist surface winds spiral in towards the center of the storm Prince William Sound Gulf of Alaska Risk of Tornadoes CANADA Highest High Medium UNITED STATES Low Tropical Cyclone Frequency High Moderately high MEXICO Atlantic Ocean What is Climate? ► Region’s general pattern of weather conditions over a long period ► 2 main factors that determine climate: 1. Temperature 2. Average precipitation Climate © 2004 Brooks/Cole – Thomson Learning the average weather patterns for an area over a long period of time (30 - 1,000,000 years). It is determined by Average Precipitation and Average Temperature which are influenced by latitude altitude ocean currents and affects where people live how people live what they grow and eat Climate is influenced by… Different climates exist because of the way air circulates over the Earth’s surface ► Determined by: ► 1. Uneven heating of the Earth’s surface - air is heated much more at the equator than the poles - tropical regions near equator are hot - polar regions are cold - temperate regions in between are moderate Climate is Influenced by… 2. Seasonal changes in temperature and precipitation - Earth’s axis is tilted, so regions are tipped toward or away from the sun as the Earth makes its year-long revolution around the sun - creates opposite seasons in northern and southern hemispheres 23.5º Spring (sun aims directly at equator) Winter (northern hemisphere tilts away from sun) Solar radiation Summer (northern hemisphere tilts toward sun) Fall (sun aims directly at equator) Climate is Influenced by… 3. Rotation of the Earth on its axis - prevents air currents from moving north and south from the equator - forms 6 huge cells of swirling air masses that transfer heat and water from one area to another Climate is Influenced by… 4. Long-term variations in solar energy striking the Earth - occasional changes in solar output and planetary shifts (wobbling as it turns) 5. Properties of air and water - heat from sun evaporates ocean water and transfers heat from ocean to the atmosphere - creates convection cells that transport heat and water from one area to another (leads to different climates) LOW PRESSURE Heat released radiates to space HIGH PRESSURE Cool, dry air Condensation and precipitation Falls, is compressed, warms Rises, expands, cools Warm, dry air Hot, wet air Flows toward low pressure, picks up moisture and heat HIGH PRESSURE Moist surface warmed by sun LOW PRESSURE Ocean Currents Factors 1-5 plus differences in water density create cold and warm ocean currents ► Currents are driven by winds and Earth’s rotation Currents do the following: 1. Redistribute heat from the sun 2. Influence climate and vegetation ► What are Upwellings? ► ► ► Movement of nutrient-rich bottom water to the ocean’s surface Steep coastal areas where the surface layer is pushed away from the shore and replaced by cold, nutrient-rich bottom water Very productive area (lots of phytoplankton and zooplankton) Upwelling Movement of surface water Wind Upwelling Nutrients El Nino-Southern Oscillation ► ► In 1. 2. 3. ENSO Pacific Ocean - normal upwellings are affected by ENSO ENSO: Winds weaken or cease Surface waters become warmer Normal upwellings are suppressed (decline in productivity and populations of fish) La Nina ► La 1. 2. 3. 4. 5. 6. 7. Sometimes El Nino is followed by La Nina (cooling counterpart) Nina generally means: More Atlantic Ocean hurricanes Colder winters in Canada and Northeast Warmer and drier winters in southeast and southwest Wetter winters in northeast Torrential rains in SE Asia Lower wheat yields in Argentina More wildfires in Florida El Niño conditions La Niña conditions +3 Temperature/Change (°F) 1982–83 1997–98 +2 +1 0 -1 -2 1950 1955 1960 1965 1970 1975 Year 1980 1985 1990 1995 2000 2005 Greenhouse Effect ► Greenhouse gases: water vapor, carbon dioxide, methane, nitrous oxide, CFCs ► Play a key role in determining the Earth’s average temperature (and thus, climate) ► Allow visible light and some radiation and UV rays from the sun to pass through troposphere Greenhouse Effect, continued ► Some of the heat escapes into space ► Some is absorbed into troposphere which warms the air ► Greenhouse effect: natural warming effect of the troposphere Greenhouse Effect Rays of sunlight penetrate atmosphere and warm the Earth’s surface Some heat escapes into space; some is absorbed by greenhouse gas molecules which warm the atmosphere As concentration of greenhouse gases rise, molecules absorb more heat…adds more heat to atmosphere Greenhouse Effect, continued ► ► ► 1. 2. 3. 4. Without greenhouse gases, Earth would be cold and lifeless Human activities (burning fossil fuels, clearing forests, etc.) create more greenhouse gases More greenhouse gases can lead to global warming, which: Alters rain patterns Shifts where we can grow crops Raises average sea levels Shifts areas where plants and animals can live Ozone Layer ► ► ► ► ► ► In stratosphere, oxygen is continuously converted to ozone and back again Caused by UV radiation from the sun Result: veil of protective ozone Normally, ozone destruction = ozone formation Ozone prevents 95% of sun’s UV rays from reaching the Earth Chemicals added to atmosphere by human activities are decreasing protective ozone Microclimates ► Local climate conditions that differ from the general climate of the region Ex: Cities whose concrete, asphalt, and bricks absorb heat and buildings block wind flow results in more heat, more smog, lower wind speeds. Biomes A biome is characterized by the climate. Tundra Flora Fauna Grasses Dwarf shrubs Cushion Plants Arctic foxes Snoeshoe hares Snowy owls Musk oxen Caribou Reindeer Treeless Tundra Flora ►Short and grouped together ►Use a minimal amount of energy Fauna ►Breeding and raising young in the summer ►Hibernation Adaptations in the Tundra Taiga Flora Fauna Coniferous trees Red deer Moose Migratory birds Elk Black bears Taiga Flora ►Trees typically are evergreens ►Plants grow in clumps Fauna ►migrate to warmer climates. ►hibernate when temperatures drop. ►produce a layer of insulating feathers or fur to protect them from the cold. Adaptations on the Taiga AKA Temperate Forest Deciduous Forest Flora Fauna Eagles Brown Bears Chipmunk Red Squirrel White-tailed deer Coyote American Beech Pecan White Oak Carpet Moss Ferns Deciduous Forest Flora ►Thin, Fauna broad, light►Birds migrate weight leaves. and mammals hibernate. ►Thick bark ►Cooler temps and limited ►Some tend to store food. sunlight causes the tree to adapt. The leaves are unable to continue producing chlorophyll and change colors. Adaptations in the Deciduous Forest Grassland Flora Fauna Buffalo Grass Sunflower Asters Coneflowers, Clover Wild Indigos Coyotes Eagles Bobcats Wild Turkey Flies and crickets Dung Beetle Bison Grassland Flora ►Narrow leaves that lose less water to evaporation. ►Have roots that extend as much as 3.5 m. for during dry periods. ►Have brightly colored flowers. Fauna ►Are grazing or burrowing animals (flat-topped teeth) ►Are colors that blend in with the plant life Adaptations in the Grassland Desert Flora Fauna Barrel Cactus Prickly Pear Cactus Joshua Trees Tumbleweeds Armadillo Lizard Coyote Tortoise Proghorn Antelope Desert Flora ►store water in the roots, stems, leaves or fruit ►develop shallow roots ►adapt the size, sheen, or texture of their leaves Fauna ►are small in size ►stay in shade or burrowing underground ►are nocturnal ►concentrate the body's fat in one place Adaptations in the Desert Rain Forest Flora Bromeliads Mangroves Nepenthes Fauna Africa Forest Elephant Bengal Tiger Chimpanzee Linn's Sloth Orangutan Toco Toucan Vampire Bat Highest biodiversity!!!! Rain Forest Temperature Precipitation The temperature in a rain forest rarely gets higher than 93 °F and rarely drops below 68 °F High humidity 7788% Large amounts of rainfall: 50 to 260 annually. 50% of the precipitation comes from its own evaporation. Found near the equator!!! Rain Forest Flora ►Thin smooth bark ►Drip tips... It is thought that these drip tips enable rain drops to run off quickly. ►Large, broad leaves ►Shallow roots Adaptations in the Rain Forest Fauna ►Prehensile tails ►Bright colors and sharp patterns ► Loud vocalizations ►Diets heavy on fruits