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Ch 5 and 6: Climate/Biomes (Terrestrial and Aquatic) Climate Weather: Climate: Average temperature and average precipitation are the 2 main factors for climate. Latitude (distance from equator) and elevation (distance above sea level) also are factors. Climate Solar energy and global air circulation 4 factors that determine global air circulations 1. uneven heating of the earths surface by the sun (equator receives more heat then the poles) 2. Seasonal changes in temperature and precipitation. 3. Rotation of the earth on its axis (causes the Coriolis effect – deflects wind to right in northern hemisphere and to the left in the southern hemisphere. 4. Properties of air, water, and land Climate (Greenhouse Effect) Greenhouse gases: Greenhouse Effect: Humans have affected the greenhouse effect by pumping excess CO2 into the atmosphere. Biomes Biomes: Ex: Desert Grasslands Chaparrals Forests Mountains Deserts Deserts: Cover 30% of the Earth’s land and found mostly in tropical and subtropical regions. Some plant and animal adaptations: Plants drop leaves and become dormant during dry time. Some plants are succulent. Some have deep roots, some have waxy coating, Most animals are small, hide during the day, reptiles and insects have thick outer coverings. Deserts Grasslands/Chaparrals Grasslands (Prairies): Tropical grasslands (savannahs) Temperate grasslands (fertile soils) Polar grasslands (tundra) Exists b/c of seasonal droughts, large herbivores, and fires. Chaparral: Grasslands Forest Biomes Forests: areas with moderate to high levels of annual precipitation. Contains many forms of trees and shrubs. Tropical rain forest: high precipitation with poor soil Temperate Deciduous Forest: Changes with seasons Evergreen Coniferous forest: Cold winters, wet summer, evergreens Temperate rain forest: coastal areas with high biodiversity Forests Mountain Biomes Covers about ¼ of earths land surface. Dramatic changes in altitude, climate, soil, and vegetation over a short distance. Many forests are found on mountains Prone to erosion 75% of all freshwater is stored as glacial ice on mountain tops Play a large role in hydrological cycle. Human Impact on Terrestrial Biomes Human activities have damaged or disturbed more than half of the world’s terrestrial ecosystems. Humans have had a number of specific harmful effects on the world’s deserts, grasslands, forests, and mountains. Organisms Live in Aquatic Life Zones Aquatic systems contain floating, drifting, swimming, bottom- dwelling, and decomposer organisms. Plankton: Phytoplankton (plant), Zooplankton (animal), Ultraplankton (photosynthetic bacteria) Nekton: Benthos: Decomposers: The Coastal Zone: Where Most of the Action Is The coastal zone: the warm, nutrient-rich, shallow water that extends from the high-tide mark on land to the gently sloping, shallow edge of the continental shelf. The coastal zone makes up less than 10% of the world’s ocean area but contains 90% of all marine species. Provides numerous ecological and economic services. Subject to human disturbance. Estuaries and Coastal Wetlands: Centers of Productivity Estuaries include river mouths, inlets, bays, sounds, salt marshes in temperate zones and mangrove forests in tropical zones. Estuaries and coastal marshes provide ecological and economic services. Filter toxic pollutants, excess plant nutrients, sediments, and other pollutants. Reduce storm damage by absorbing waves and storing excess water produced by storms and tsunamis. Provide food, habitats and nursery sites for many aquatic species. Figure 6-7 Rocky and Sandy Shores: Living with the Tides Organisms experiencing daily low and high tides have evolved a number of ways to survive under harsh and changing conditions. Gravitational pull by moon and sun causes tides. Intertidal Zone: area of shoreline between low and high tides. Organisms in intertidal zone develop specialized niches to deal with daily changes in: Temperature Salinity Wave action Barrier Islands Low, narrow, sandy islands that form offshore from a coastline. Primary and secondary dunes on gently sloping sandy barrier beaches protect land from erosion by the sea. Figure 6-10 Threats to Coral Reefs: Increasing Stresses Biologically diverse and productive coral reefs are being stressed by human activities. Figure 6-11 Biological Zones in the Open Sea: Light Rules Euphotic zone: Nutrient levels low, dissolved O2 high, photosynthetic activity. Bathyal zone: No photosynthetic activity, zooplankton and fish live there and migrate to euphotic zone to feed at night. Abyssal zone: Very cold, little dissolved O2. Effects of Human Activities on Marine Systems: Red Alert Human activities are destroying or degrading many ecological and economic services provided by the world’s coastal areas. Figure 6-13 FRESHWATER LIFE ZONES Freshwater life zones include: Standing (lentic) water: Flowing (lotic) systems: such as streams and rivers. Figure 6-14 Lakes: Water-Filled Depressions Lakes are large natural bodies of standing freshwater formed from precipitation, runoff, and groundwater seepage consisting of: Littoral zone: Limnetic zone: Profundal zone: Benthic zone: Effects of Plant Nutrients on Lakes: Too Much of a Good Thing Plant nutrients from a lake’s environment affect the types and numbers of organisms it can support. Oligotrophic: Eutrophic: Freshwater Inland Wetlands: Vital Sponges Inland wetlands act like natural sponges that absorb and store excess water from storms and provide a variety of wildlife habitats. Filter and degrade pollutants. Reduce flooding and erosion by absorbing slowly releasing overflows. Help replenish stream flows during dry periods. Help recharge ground aquifers. Provide economic resources and recreation Figure 6-18 Impacts of Human Activities on Freshwater Systems Dams, cities, farmlands, and filled-in wetlands alter and degrade freshwater habitats. Dams, diversions and canals have fragmented about 40% of the world’s 237 large rivers. Flood control levees and dikes alter and destroy aquatic habitats. Cities and farmlands add pollutants and excess plant nutrients to streams and rivers. Many inland wetlands have been drained or filled for agriculture or (sub)urban development.