2 Atmosphere Weather is short term conditions of atmosphere Climate is long term conditions5 major processes influence climate/weather: unequal heating of earth, convection currents, Coriolis effect, tilt, and oceansAtmosphere has 4-layers:Troposphere (0-20km): bottom layer, densest, where most weather and mixing occurs, temps get colder with heightStratosphere (20-50km): second layer, gets warmer with height, contains ozone layer that absorbs UV lightMesosphere (50-80km) – third layer, coldest, meteorites burn upThermosphere – top layer, warmest, absorb gamma raysAtmosphere protects organisms from radiation and it regulates temperatures
4 1. Unequal Heating Atmosphere is heated unevenly for 2 reasons Tilt of the earthSome areas on earth reflect more sunlight than other areas (albedo)White surface has higher albedo than black surfaceThis uneven heating of the atmosphere drives convection currents in the atmosphere
6 2. Atmospheric Convection Currents Air has 4 properties that determine how it will circulateDensity: less dense air rises (warm), more dense air sinks (cold)Water vapor capacity: warm air can hold more water vapor (saturation point) which is less denseAdiabatic heating/cooling:When air rises, pressure decreases and air expands and temps lower due to less friction between air moleculesWhen air sinks, pressure increases and air compresses and temps rise due to more friction between air moleculesLatent heat release: when air condenses, the energy that evaporated it is released and air warms
7 (2). Formation of Convection Currents Air rises in warm, moist tropicsRising air experiences lower atmospheric pressure and adiabatic cooling until it reaches saturation pointThis leads to condensation which releases latent heatEventually air cools and spreads out and begins to sink around 30⁰ latitude (deserts)When sinking air hits the ground, it spreads in all directions completing the cycle, called a Hadley cellAir re-converges at the equator, called the intertropical convergence zone (ITCZ)Polar regions cause additional Hadley cells
9 3. Earth’s Rotation and Coriolis Effect Earth rotates faster at equator than polesObjects’ paths get deflected due to the rotation of earth. This is known as the Coriolis effectThis deflects winds and sets up weather patternsTrade winds blow towards the equator between 0- 30°. They meet at the equator and rise creating calm winds called the doldrumsWhere the air sinks at 30° is the horse latitudesAir moves north from here, Coriolis force deflects it to right, and get westerlies (40°-60°)At poles, the air sinks and moves towards the equator, but gets deflected to right. This creates polar easterlies
12 4. Earth’s Tilt and Seasons Earth is tilted 23.5⁰When northern hemisphere is pointed towards the sun they experience summerWhen northern hemisphere is pointed away from the sun they experience winter (southern hemisphere is opposite)Vernal/automnal equinoxes, everywhere receives 12h daylightPoles have 6 months of darkness and 6 months of daylight
15 5. Ocean CurrentsCurrents driven by temp, gravity, prevailing winds, Coriolis effect, and continentsWater is warmer at the equator, so it expands and rises. This makes the water higher then the rest of earth and gravity takes overWinds and Coriolis effect start ocean currents and deflect them. Called gyres (transport heat)Upwelling (rising of water) occurs along coastlinesThermohaline circulation is when water is saltier, making it more dense, so it sinksENSO (El Nino – Southern Oscillation– when ocean currents change direction, thus affecting climates
17 Rain ShadowsAir rises on one side of a mountain range and moisture condenses outOn other side, air sinks preventing clouds and it remains dryDry region is called a rain shadow
18 Altitudes create “latitudinal” patterns Vegetative communities rapidly change along mountain slopesThe climate varies with altitudeA mountain climber in the AndesBegins in the tropics and ends on a glacierRainshadow effect = air going over a mountain releases moistureCreating an arid region on the other side
19 BiomesBiomes are large regions characterized by a specific type of climate and certain types of plant and animal communitiesLargest category scientists use to classify ecosystemsEach biome has many ecosystemsBiomes described by vegetation because that determines organisms and amount of vegetation is determined by climateAt altitude and latitude increase, temps decrease
22 Tundra Climate: Very cold year around and little precip (driest biome) Location: North of the arctic circlePlants:Mostly mosses and lichen (which don’t need soil)Rest of plants are low and have wide roots to keep them stable in windsSoil is permafrost which makes it hard for trees to grow, and low in nutrientsAnimals: Birds common in summer, caribou, wolves, deer, rabbits, foxes, bearsThreats: Oil excavation and pollution. Food chain is simple, so small change has dramatic consequencesOther: CO2 sink, none in southern hemisphere
25 Boreal Forest (taiga)Climate: Long cold winters, short mild summers, and fairly dryLocations: Just below the arctic circleVegetation (slow decomposition allows for little):Dark forest floor because thick canopy blocks sunlightBranches near tops of treesTrees are conifers (seeds in a cone)Leaves thin, pointy, and waxy to store water and shed snowAnimals:Many insects in summerMigratory birds to feed on insectsSome large herbivores and thick-coated carnivoresThreats: global warming and oil excavationOther: soil low in nutrients, lots of lakes from last ice age
28 Temperate Rain Forest and Temperate Deciduous Forest Climate:Temperate rain forest = wet year around with moderate tempsTemperate deciduous forest = Moderate precip and large temp range (4-seasons)Location: TRF = northwest US, TDF = Mid latitudesPlants:TRF = Draped with mosses, lichens, and fernsTDF = Many tall trees and many shrubs since plenty of light. Lose leavesAnimals:Many animals and insectsIn TDF, many animals fly south or hibernate and shed furThreats: overdevelopment, logging, fossil fuels, agriculture
34 Woodland/Shrubland Chaparral Climate: Dry and warm, but not quite desert dryLocation: Mostly around 30° latitude near waterPlants:Many evergreen shrubsPlants oily to burn and to retain waterAnimals: most animals camouflage, many have scales, and most smallThreats: human developmentOther: wild wild west
37 Tropical Rain Forest Climate: warm and wet year around Animals: Location: near the equatorAdapt to use resources, escape predators, and capture preyPlants:Built to climb treesEmergent trees get direct sunlightBright colors, spikes, loud noises…Dense canopy absorbs 95% of sunlightThreats:Understory has large leaves to absorb little lightDestroyed for logging, oil, and agricultureLeaves have drip tips for water to runoffAnimals and plants are used for tradingMany vines climb trees to reach sun
40 Savannah Separate desert biomes from tropical rain forest biomes Climate: Short wet season, long dry season, and warm year roundLocation: Close to the equatorPlants:Full of grasses (many sharp and bitter) with scattered treesTrees have large horizontal roots to absorb water in dry season and thick bark to survive firesAnimals:Full of grazing animals and their predatorsHerbivores have many heights to limit competitionMany have long legs or wings to migrateThreats: poaching, hunting, agriculture, grazingOther: Many grassfires
43 Temperate GrasslandsClimate: Hot summers, cold winters, and inconsistent precipitationLocations: Interior of continents, often surrounded by mountains which limit rainfallPlants:Very fertile soilMany grasses and flowers which are perennialsPrairies = tall grasses (wetter) Steppes = short grasses (drier)Very few trees because limited rainfallAnimals: Many smaller animals that can hide in grass and their predatorsThreats: over farming
46 DesertClimate: very dry and mostly warm to very hot year around (with large daily temp range)Location: Most around 30° latitudePlants:Little to no vegetationPlants called succulents have thick, fleshy stems to store water (cactus).Spines keep thirsty animals away and conserve waterAnimals:Animals are mostly small reptiles, spiders, and insectsMost have shells or scales to trap water inMost bury themselves undergroundMost nocturnalOther:1. Soil rich in minerals but low in nutrients2. Can be cold
49 Aquatic EcosystemsAquatic ecosystems are categorized by salinity, depth, nutrients, and water flowStreams and rivers: rivers larger and carry more water. Very little plant matter (most washes from land). Slower they flow typically means more lifeLakes and ponds: have standing water that gets too deep to support rooted plants. Lakes typically larger and have water flowing in an outLittoral zone: shallow area near shore. Algae and cattails. Most lifeLimnetic zone: not rooted plants. Phytoplankton are producers. Extends as deep as sunlight penetratesProfundal zone: region below where sunlight reaches. Not productive (few decomposers)Benthic zone is the muddy bottom (low temps and oxygen levels)
51 Freshwater WetlandsWetlands are land covered with water during parts of the yearMost found in the southeastern USFilter pollutants and sedimentsPrevent flooding by storing excess waterProvide homes for many types of organismsRecycle nutrients and sinks (CO2)2-types: marshes and swampsMarshes do not contain woody plantsSwamps contain woody plantsLow oxygen levels, so slow decay
53 Salt Water Wetlands Dry during low tide, wet during high tide An estuary is where freshwater meets saltwater. Very productive ecosystem with large biodiversity:Many nutrients trapped where currents meetTides circulate nutrientsHigh level of light penetrationMany plants in and aroundSalt marsh is a muddy wetland near estuary where nutrients pile upDry during low tide, wet during high tideMangrove swamps are swamps in tropical areas that are dominated by mangrove trees. Protect shore from erosion and provide shelterRocky shores have many more plants and animals than sandy ones.
55 Coral Reefs Coral reefs are limestone ridges built by tiny animals It is made of skeletons that accumulate (limestone)Found in shallow, tropical waterThey eat microscopic organisms with tentaclesSymbiosis with algae (coral release CO2, algae uses that for photosyn and creates sugars that coral uses)One of most diverse ecosystems in worldIf water temp or salinity changes, they can dieOil spills, sewage, pesticide, runoff, harvesting (for jewelry) and over fishing have killed reefs
57 The Open OceanThe depth that light can penetrate in the open ocean is dependent on the amount of sediment and algae suspended in the water.Photic zone- the zone that receives enough light to allow photosynthesis to occur.Aphotic zone- the deeper water that lacks sufficient light for photosynthesis.Chemosynthesis- The process that occurs in the aphotic zone when some species of bacteria use methane and hydrogen sulfide to generate energy.
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