unit 4 Flashcards
Igneous Rocks
Formed by the cooling and solidification of magma/lavaClassified by crystal size, texture, and compositionThe crystal size is influenced by the rate of cooling (rapid cooling = small/no crystals and glassy) (slow cooling = large crystals)Composition is influenced by minerals present (granitic = lighter, less dense material) (basaltic = darker, denser materials)
Sedimentary Rocks
Formed from sediments cementing together, the evaporation of seawater, or the deposition of organic materialOnly type that contains fossils Often deposited in layers in an aquatic environment
Metamorphic Rocks
Formed by extreme heat and pressureDistortion and banding
Th theory of Plate tectonics
The convection currents in the mantle are what drive continental drift in the crust. (Mantle material near the core is hotter, becomes less dense, and it rises towards the surface. The material near the surface is cooler and pushed out of the way, and the plates above are dragged along with the surface)
Converging Plate Boundaries
Converging plate boundaries (two plates converging together)Uplift: both are pushed upwardSubduction: the denser plate is pushed down and underFeatures: mountains, volcanoes, islands, earthquakes, trenches
Divergent Plate Boundaries
Divergent plate boundary ( two plates moving away from each otherSeafloor spreading occurs, where the seafloor is growing because new crust is being createdFeatures: mid ocean ridge, rift valleys, volcanoes, hydrothermal vent communities, earthquakes
Transform Plate Boundaries
Transform plate boundaries (two plates sliding past each other in opposite directions)Ex san andreas fault, where lots of earthquakes occur
Volcanoes
Classified as active, dormant, or extinct. Eruptions occur when magma is released out of the crust Some are a slow ooze of lava, others are huge explosionsShort term effects: catastrophic destructions, new land massesLong term effects: climate change: release aerosols like fine ash are released into the atmosphere where they reflect light away from earth, lowering global temps.
Earthquakes
As plates move, friction builds along the boundaries and faults. Sometimes, the plates bet stuck, and potential energy continues to build after they got stuck. An earthquake occurs when the buildup is suddenly released sending seismic waves in all directionsTypes of waves: P waves(fastest, arrive first) and S waves (arrive second)Can create massive damage around the epicenterAre the primary cause of tsunamis
Weather vs climate
Weather is the current condition of the atmosphere. Short term, changes rapidlyClimate is the general pattern of weather conditions, observed over long periods of time for a specific location. These patterns exist after 30+ years, even thousands, and change very slowly if at all
Incoming Solar radiation
Can be shortened to insolation. Most of Earth’s heat/energy comes from the Sun, but it’s radiation is not evenly spread across the surface. Earth is tilted off at a 23.5 degree angle, and the equator is usually the area of highest insolation while the poles are the lowest. Depends on latitude & time of year
Seasons
The angle of insolation for a particular region is influenced by the time of year. As a pole is angled towards the sun, more angle of insolation (summer). As a pole is angled away from the sun, less angle of insolation (winter).The more horizontal an area is to the sun, the more insolation it gets
Air and ocean currents (how they impact each other)
Earth receives most of the sun’s energy at the equator which creates convection currentsWater has a higher specific heat, it absorbers more of the energy from the sun. This warms up the area’s atmosphere even more (The ground can radiate this heat back as well)This mass movement of warm air/surface water influences regional climates/biomes
Vertical Air currents
Convections cells develop vertically in the atmosphere and line up along specific latitudesThese are HADLEY CELLS near the equatorFERREL CELLS at the mid latitudesAnd POLAR CELLS near the polesWhen two cells meet and air is sinking, there is dry, high pressure air that creates arid biomes (deserts)Where two cells meet and air is rising, there is moist, low pressure air that creates humid/stormy biomes (rainforests)SEE DIAGRAM 1
global surface winds
Uneven heating causes air to move across the ground from areas of high pressure to low pressure. Thus, this always means winds blow from low latitudes to high latitudes. However, due to the Coriolis effect, the winds do not move in straight lines. These winds have been critical to maritime trade in the pastSEE DIAGRAM 2
Coriolis Effect
The APPARENT deflection of an object’s path due to the rotation of the earth.Because the earth is a sphere and the equator is wider than the poles, the earth is spinning faster at the equator (since it has a farther distance to cover). As the object moves from the equator north, it APPEARS to bend to the right since the earth is spinning SLOWER the further north you go (opposite in the south)
Rain Shadow Effect
Air evaporates over the ocean and is moved on land by prevailing windsAs the air is pushed UP the windward side of the mountain, it cools and condenses.T his causes the moisture to fall out as precipitation. Usually leads to high productivityThe now dry air is pushed over the peak and down the leeward side causing it to warm and expandThis warming and expansion promotes evaporation, creating an arid biome(windward faces the wind and leeward is protected from it)
Physical Weathering
Water: freezes into cracks of rocks and expands, forcing the rock to split or crackedTemperature: sometimes ice or other large changes in temperature cause a rock to crack, split, melt, etc because minerals expand or contractConstant light pressure from wind or water can also change a rock overtimeBiological agents: like plant roots or burrowing animals also take advantage of cracks and increase surface areoftentimes , physical weathering exposes more surface area and makes rock more vulnerable to further degradation, and increases rate of chemical
Chemical Weathering
Releases nutrients from rock which is good for organismsOccurs more rapidly on newly exposed minerals (primary minerals)It alters primary minerals to form secondary mineralsRain: acids in rain react with rock to form ions and particles etcLichen: break down rock with weak acidsRocks containing compounds that dissolve easily weather easilyThe chemical composition of rock and the pH of water that contacts it can change the reaction that occursEx. carbonic acid in water flows over limestone, it dissolves the stone and makes cool cave systemsSulfur emitted from fossil fuels forms Sulfur dioxide in atmosphere and degrades rock rapidly through acid precipitationAcid precipitation on soil can chemical weather the soil and release elementsBecause weathering certain granite consumes carbon dioxide from the atmosphere, weathering can reduce CO2 in the atmosphere
Erosion
you know this
How Soil is Formed
It takes hundreds to thousands of years to form, it is the result of physical/chemical weathering of rocks and accumulation of detritus (waste) from the biosphere Young soul has less organic matter and nutrients than developed soil, while very old soils are also sometimes nutrient poor because they’ve been sucked dry5 factors decide properties: parent material, climate, topography, organisms, time for formation
Soil Horizonsssss
O horizon: Made of organic matter like leaves, and is mostly found in forests/grasslands. (Humus) The lowest layer of the O horizon, where most matter is fully decomposed and does not contain recognizable plant or animal components. “Humic material” can sometimes be sparsely found lower down as wellA horizon: Also known as topsoil, a mixed layer of both organic and mineral materials. Very important in agricultureE horizon: Sometimes it forms in acidic soils. Where iron, aluminum and organic matter is dissolved and transported from above to the B horizonB horizon: Also known as subsoil, mostly made of minerals but may have a bit of nutrients. C horizon: The least weathered horizon and is very similar to parent materialSEE DIAGRAM 3
Physical Properties of soil
TEXTURE, POROSITY, PERMEABILITY (all decided by the % mixture of sand, silt and clay)
Chemical Properties of soil
Clay particles in a soil contribute most to chemical properties because they attract positively charged mineral ions (cations) and have a - charge themselves. cations are taken in and then used for nutrients by the plantsA soil’s ability to absorb and release cation is called its cation exchange capacity (CEC) (soils with high CEC are better for agriculture). The CEC is a function of the amount and type of clay particles presentIf a soil is >20% clay, there is too much water retention for agriculture so too much CEC causes less permeability
Soil bases vs acids
Soil acids are usually harmful for plants, while bases aid plant growthAll soil bases except sodium are crucial for plant nutritionex. bases: calcium, magnesium, potassiumex. acids: aluminum, hydrogen
Layers of the Atmosphere
TROPOSPHERE: Where most of the atmosphere’s N2, O2, and H2O is found. Has a lot of circulation within and thus is where weather occursTemperature decreases as it gets farther from the surfaceSTRATOSPHERE: Less dense than the troposphere, and holds the ozone layer, a pale blue gas made of O3 that protects the earth from most of the sun’s UV-B and UV-C radiation. The radiation is converted to infrared radiation and released as heatThe stratosphere’s temp increases as it gets higher up (more sun rays)MESO/THERMO/EXOSPHERE: They are all less and less pressurized and denseThe thermosphere is also critical for UV protection, and is where the northern lights occur
What is a watershed
A watershed is all of the land in a given landscape that drains into a particular stream lake or other body of water
Parts of a watershed
The divide: line marking the highest points around a body of water. Separates one watershed from another and create an outlineTributaries: smaller streams and river that feed into the main riverRiver: the main source of water flowing into the largest water feature in a regionDelta: where the largest tributaries empty into the main body of water and located at the mouth of a river. Groundwater/aquifer: water that has infiltrated underground and is held in sedimentsSource Zone: also known as headwaters, fed by precipitation or snow/ice meltTransition zone: portion of the system between the head and mouth of riverFloodplain: usually flat and wide open space along the river, and represent where the water goes when the river floods.
Effects of Vegetation on Watershed
Slow the movement of water through the soil and drastically decrease the amount of erosion that occurs
Effects of Topography on Watershed
steeper slopes have faster flow of water (and permeability affects this as well) and larger watersheds collect more water
Intermediate Disturbance Hypothesis
The intermediate disturbance hypothesis says that ecosystems experiencing intermediate levels of disturbance will favor a higher diversity of species than those with high or low disturbance levelsWhen disturbances are rare, there is intense competition and eventually only a few populations dominate the entire system. When they are large, it’s hard for a species to get an upper hand at all
Groundwater
The area closest to the surface holds little groundwater, below this area there is a space where the pores are 100% filled with water. This is the zone of saturation. The top of this zone is called the water table, and it changes depending on water and human use. When an area has water ponding on the surface, it is oversaturatedRate of infiltration and the amount of water the ground can hold is determined by the sediment size of the soilDirectly related to porosity and permeability
Aquifers
Regions with deep, saturated sediments and represent a significant source of freshwater (can flow)Unconfined: aquifer is covered in permeable soil (rechargeable)Confined: capped with an impermeable layer and the water is under pressure (harder to recharge)Some are renewable resources others aren’tPollutants are nearly impossible to remove from an aquifer
Cone of Depression
As water is pumped out of an aquifer, the water table subsides near the well called the cone of depression. THe faster it is the steeper it is and it acts like a hill
The Trade Winds
Northern Trade WInds (north of equator) and Southern Trade Winds (south of)Formed due to the coriolis effectSurface winds moving towards the equator are deflected to the westCreates a prevailing wind: a major surface wind that blows almost constantly
Neutral Conditions (Walker Circulation)
Trade winds blow across the pacific and push the warm surface off the coast of Australia (east to west)The warm water evaporates and creates stormy conditions s in Australia and the other surrounding islandsWhen the air comes back to south America, its now dry and dense (descends)This causes upwelling from deep cold water that comes to the surface, which is also nutrient richThis addition of nutrients trigger algae blooms which support a diverse range of marine species
El Nino conditions
Happens when TRADE WINDS are WEAKER than normal. The westerly winds then come in to change things upEvaporation spreads east as well and there’s more rain in the middle of the pacific/ eastern pacificWarm water is not fully pushed around (stays in the east). This means the warm water stays in place and upwelling is much weaker, and this brings less nutrients up to the surface and the ecosystem collapses (bad for the economy as well)Effects (general):Warm and dry conditions in southern and eastern Australia and southeast Asia, Drier winter conditions in Brazil and South Africa, Wetter than normal along the gulf coast and the West Coast of Tropical South America, Milder winter in Alaska and CanadaDIAGRAM 4
