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Chapter 4 Climate and Biomes.

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Presentation on theme: "Chapter 4 Climate and Biomes."— Presentation transcript:

1 Chapter 4 Climate and Biomes

2 Atmosphere Weather is short term conditions of atmosphere
Climate is long term conditions 5 major processes influence climate/weather: unequal heating of earth, convection currents, Coriolis effect, tilt, and oceans Atmosphere has 4-layers: Troposphere (0-20km): bottom layer, densest, where most weather and mixing occurs, temps get colder with height Stratosphere (20-50km): second layer, gets warmer with height, contains ozone layer that absorbs UV light Mesosphere (50-80km) – third layer, coldest, meteorites burn up Thermosphere – top layer, warmest, absorb gamma rays Atmosphere protects organisms from radiation and it regulates temperatures


4 1. Unequal Heating Atmosphere is heated unevenly for 2 reasons
Tilt of the earth Some areas on earth reflect more sunlight than other areas (albedo) White surface has higher albedo than black surface This 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 circulate Density: 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 dense Adiabatic heating/cooling: When air rises, pressure decreases and air expands and temps lower due to less friction between air molecules When air sinks, pressure increases and air compresses and temps rise due to more friction between air molecules Latent 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 tropics Rising air experiences lower atmospheric pressure and adiabatic cooling until it reaches saturation point This leads to condensation which releases latent heat Eventually 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 cell Air 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 poles Objects’ paths get deflected due to the rotation of earth. This is known as the Coriolis effect This deflects winds and sets up weather patterns Trade winds blow towards the equator between 0- 30°. They meet at the equator and rise creating calm winds called the doldrums Where the air sinks at 30° is the horse latitudes Air 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 23.5⁰ When northern hemisphere is pointed towards the sun they experience summer When northern hemisphere is pointed away from the sun they experience winter (southern hemisphere is opposite) Vernal/automnal equinoxes, everywhere receives 12h daylight Poles have 6 months of darkness and 6 months of daylight



15 5. Ocean Currents Currents driven by temp, gravity, prevailing winds, Coriolis effect, and continents Water is warmer at the equator, so it expands and rises. This makes the water higher then the rest of earth and gravity takes over Winds and Coriolis effect start ocean currents and deflect them. Called gyres (transport heat) Upwelling (rising of water) occurs along coastlines Thermohaline circulation is when water is saltier, making it more dense, so it sinks ENSO (El Nino – Southern Oscillation– when ocean currents change direction, thus affecting climates


17 Rain Shadows Air rises on one side of a mountain range and moisture condenses out On other side, air sinks preventing clouds and it remains dry Dry region is called a rain shadow

18 Altitudes create “latitudinal” patterns
Vegetative communities rapidly change along mountain slopes The climate varies with altitude A mountain climber in the Andes Begins in the tropics and ends on a glacier Rainshadow effect = air going over a mountain releases moisture Creating an arid region on the other side

19 Biomes Biomes are large regions characterized by a specific type of climate and certain types of plant and animal communities Largest category scientists use to classify ecosystems Each biome has many ecosystems Biomes described by vegetation because that determines organisms and amount of vegetation is determined by climate At altitude and latitude increase, temps decrease



22 Tundra Climate: Very cold year around and little precip (driest biome)
Location: North of the arctic circle Plants: Mostly mosses and lichen (which don’t need soil) Rest of plants are low and have wide roots to keep them stable in winds Soil is permafrost which makes it hard for trees to grow, and low in nutrients Animals: Birds common in summer, caribou, wolves, deer, rabbits, foxes, bears Threats: Oil excavation and pollution. Food chain is simple, so small change has dramatic consequences Other: CO2 sink, none in southern hemisphere



25 Boreal Forest (taiga) Climate: Long cold winters, short mild summers, and fairly dry Locations: Just below the arctic circle Vegetation (slow decomposition allows for little): Dark forest floor because thick canopy blocks sunlight Branches near tops of trees Trees are conifers (seeds in a cone) Leaves thin, pointy, and waxy to store water and shed snow Animals: Many insects in summer Migratory birds to feed on insects Some large herbivores and thick-coated carnivores Threats: global warming and oil excavation Other: 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 temps Temperate deciduous forest = Moderate precip and large temp range (4-seasons) Location: TRF = northwest US, TDF = Mid latitudes Plants: TRF = Draped with mosses, lichens, and ferns TDF = Many tall trees and many shrubs since plenty of light. Lose leaves Animals: Many animals and insects In TDF, many animals fly south or hibernate and shed fur Threats: overdevelopment, logging, fossil fuels, agriculture






34 Woodland/Shrubland Chaparral
Climate: Dry and warm, but not quite desert dry Location: Mostly around 30° latitude near water Plants: Many evergreen shrubs Plants oily to burn and to retain water Animals: most animals camouflage, many have scales, and most small Threats: human development Other: wild wild west



37 Tropical Rain Forest Climate: warm and wet year around Animals:
Location: near the equator Adapt to use resources, escape predators, and capture prey Plants: Built to climb trees Emergent trees get direct sunlight Bright colors, spikes, loud noises… Dense canopy absorbs 95% of sunlight Threats: Understory has large leaves to absorb little light Destroyed for logging, oil, and agriculture Leaves have drip tips for water to runoff Animals and plants are used for trading Many 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 round Location: Close to the equator Plants: Full of grasses (many sharp and bitter) with scattered trees Trees have large horizontal roots to absorb water in dry season and thick bark to survive fires Animals: Full of grazing animals and their predators Herbivores have many heights to limit competition Many have long legs or wings to migrate Threats: poaching, hunting, agriculture, grazing Other: Many grassfires



43 Temperate Grasslands Climate: Hot summers, cold winters, and inconsistent precipitation Locations: Interior of continents, often surrounded by mountains which limit rainfall Plants: Very fertile soil Many grasses and flowers which are perennials Prairies = tall grasses (wetter) Steppes = short grasses (drier) Very few trees because limited rainfall Animals: Many smaller animals that can hide in grass and their predators Threats: over farming



46 Desert Climate: very dry and mostly warm to very hot year around (with large daily temp range) Location: Most around 30° latitude Plants: Little to no vegetation Plants called succulents have thick, fleshy stems to store water (cactus). Spines keep thirsty animals away and conserve water Animals: Animals are mostly small reptiles, spiders, and insects Most have shells or scales to trap water in Most bury themselves underground Most nocturnal Other: 1. Soil rich in minerals but low in nutrients 2. Can be cold



49 Aquatic Ecosystems Aquatic ecosystems are categorized by salinity, depth, nutrients, and water flow Streams and rivers: rivers larger and carry more water. Very little plant matter (most washes from land). Slower they flow typically means more life Lakes and ponds: have standing water that gets too deep to support rooted plants. Lakes typically larger and have water flowing in an out Littoral zone: shallow area near shore. Algae and cattails. Most life Limnetic zone: not rooted plants. Phytoplankton are producers. Extends as deep as sunlight penetrates Profundal zone: region below where sunlight reaches. Not productive (few decomposers) Benthic zone is the muddy bottom (low temps and oxygen levels)


51 Freshwater Wetlands Wetlands are land covered with water during parts of the year Most found in the southeastern US Filter pollutants and sediments Prevent flooding by storing excess water Provide homes for many types of organisms Recycle nutrients and sinks (CO2) 2-types: marshes and swamps Marshes do not contain woody plants Swamps contain woody plants Low 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 meet Tides circulate nutrients High level of light penetration Many plants in and around Salt marsh is a muddy wetland near estuary where nutrients pile up Dry during low tide, wet during high tide Mangrove swamps are swamps in tropical areas that are dominated by mangrove trees. Protect shore from erosion and provide shelter Rocky 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 water They eat microscopic organisms with tentacles Symbiosis with algae (coral release CO2, algae uses that for photosyn and creates sugars that coral uses) One of most diverse ecosystems in world If water temp or salinity changes, they can die Oil spills, sewage, pesticide, runoff, harvesting (for jewelry) and over fishing have killed reefs


57 The Open Ocean The 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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