AP Environmental Science: Unit 4 Review - Earth Systems

Plate Boundaries/Tectonics

• plate tectonics - theory of the large scale motions of the plates located in Earth's lithosphere
• convergent boundaries -  when two plates collided, results in mountains, volcanoes, island arcs, earthquakes
• divergent boundaries - when two plates move away from each other, results in seafloor spreading, rift valleys, volcanoes, earthquakes
• transform boundaries - when two plates slide past each other, results in earthquakes
• earthquakes occur at fault lines

Soil Formation 

• soils are formed when parent material is weathered and eroded
• soils are usually categorized by horizons (layers)
• o horizon - organic matter is various stages of decomposition
• a horizon - (topsoil), overlying organic material
• b horizon - (subsoil), accumulation of nutrients and metals
• c horizon - (subsoil), most similar to parent material

 Causes of Erosion

• topography - slope of land, affects erosion
• deforestation - lack or roots holding down soil
• overgrazing - overeating of top layer of soil
• pesticide/fertilizers - changes the chemical components of soil
• tillage - turning/breaking top layer of soil
• solutions - maintain plant cover, no till farming, strip/contour cropping or plowing

Soil Composition and Properties

• water holding capacity - total amount of water soil can hold
• soil texture triangle - diagram that allows for the comparison and identification of soil types based on the percentage of silt, clay, and sand it contains

Earth's Atmosphere

• 78% Nitrogen
• 21% Oxygen
• 1% trace gases
• layers of Earth's atmosphere - troposphere, stratosphere, mesosphere, thermosphere, exosphere
• troposphere -the layer of the atmosphere extending from the Earth's surface, all of Earth's weather occurs in this layer
• stratosphere - layer of the atmosphere above the troposphere and bellow the mesosphere , contains the ozone layer 
• mesosphere - atmospheric layer above the stratosphere and below the thermosphere
• thermosphere - atmospheric layer above the mesosphere
• exosphere - the outermost region of a Earth's atmosphere
• tilt of the Earth = seasons
• rain shadow effect -  region of land that has become drier because a higher elevation area blocks precipitation from reaching the land

Global Wind Patterns

• coriolis effect - because the earth is spinning, although winds are traveling in a straight line, they seem to deflect or change direction. From their origin, wind deflects to the right in the N hemisphere & to the L in the S hemisphere
• types of convection cells - Hadley, ferrel, polar
• hadley cells - 0 - 30 degrees N & S
• ferrel cells - 30 - 60 degrees N & S
• polar cells - 60 - 90 degrees N & S

El Nino and La Nina

• el nino and la nina - phenomena associated with changing ocean surface temperatures in the Pacific Ocean
• normal conditions - winds flow from East to West, and push the warm water from South America over to Australia, water off the coast of S. America is cool. As the warm surface water leaves off the coast of S. America, it is replaced with cold, nutrient rich water
• la nina -  extreme version of normal conditions, trade winds from east to west speed up, pushing warm water even further away from the Pacific & the Americas and more towards Australia and Atlantic, unusually cool surface water temperatures along Americas’ coasts, hurricane activity in the Pacific declines but it increases in the Atlantic since it is unusually warmer 
• el nino -  east to west trade winds in the tropics weaken or sometimes reverse direction, warm water is pushed to western coasts of the Americas and causes the surface water to heat up, cool water is unable to rise along Americas’ western coasts resulting in less food for predators and fisherman