Ap gov unit 4 notes

Plate Tectonics

Objectives, Essential Knowledge, and Skills

• Learning Objective (ERT-4.A)

  • Describe the geological changes and events that occur at convergent, divergent, and transform plate boundaries.

• Suggested Skill (2.C)

  • Visual Representations: Explain how environmental concepts and processes represented visually relate to broader environmental issues.

• Essential Knowledge

  • ERT-4.A.1: Convergent boundaries can result in the creation of mountains, island arcs, earthquakes, and volcanoes.

  • ERT-4.A.2: Divergent boundaries can result in seafloor spreading, rift valleys, volcanoes, and earthquakes.

  • ERT-4.A.3: Transform boundaries can result in earthquakes.

  • ERT-4.A.4: Maps that show the global distribution of plate boundaries can be employed to determine the location of volcanoes, island arcs, earthquakes, hot spots, and faults.

  • ERT-4.A.5: An earthquake occurs when stress overcomes a locked fault, releasing stored energy.

Earth's Structure

• Core: Dense mass composed of iron, nickel, and radioactive elements that releases massive amounts of heat (approximately 9,300°F).

  • Inner Core: Solid state.

  • Outer Core: Liquid state.

• Mantle: Liquid layer of magma surrounding the core, kept liquefied by the intense heat from the core.

• Asthenosphere: Solid but flexible outer layer of the mantle, lies beneath the lithosphere.

• Lithosphere: Thin, brittle layer of rock floating on top of the mantle, is broken up into tectonic plates.

• Crust: Very outer layer of the lithosphere and constitutes the Earth's surface.

Plate Tectonic Theory

• The lithosphere is fragmented into tectonic plates, which are large sections of crust that move slowly due to the underlying liquid layer (asthenosphere).

• Plate interactions form various geological features observed on Earth.

Divergent Plate Boundary

• Definition: Plates move away from each other.

• Mechanism: Rising magma plume from the mantle forces plates apart.

• Results in:

  • Mid-oceanic ridges (underwater mountain ranges)

  • Volcanoes

  • Seafloor spreading

  • Earthquakes

  • Rift valleys

Convergent Plate Boundary

• Definition: Plates move towards each other.

• Mechanism: Leads to subduction, where the denser plate is forced beneath another plate.

• Results in:

  • Mountains

  • Earthquakes

  • Volcanoes

Transform Fault Plate Boundary

• Definition: Plates slide past each other in opposite directions.

• Results in:

  • Earthquakes

Plate Boundary Interactions

Divergent Boundaries

1. Magma heated by Earth’s core rises towards lithosphere.

2. Rising magma cools and expands, forcing oceanic plates apart; creates mid-ocean ridges, volcanoes, and spreading zones.

3. Solidified magma forms new lithosphere (new crust).

Convergent Boundaries

• Subduction Zone:

  • Continental-Continental: One plate subducts beneath another, forming mountains (e.g., Himalayas).

  • Oceanic-Continental: Denser oceanic plate subducts beneath continental plate, melts back into magma, forcing magma to surface, forming coastal mountains (e.g., Andes), volcanoes, trenches, and tsunamis.

  • Oceanic-Oceanic: One oceanic plate subducts under another, forming mid-ocean volcanoes (island arcs) and offshore trenches.

Transform Fault Boundary

• Definition: Plates sliding past each other create a fault, where rough edges get stuck, building pressure until released.

• Results in earthquakes when the stress overcomes the locked fault.

Earthquakes

• Most frequently caused by convergent boundaries, but also occur along transform boundaries.

• Epicenter: Location on the Earth's surface directly above where the earthquake starts.

• Focus: Location beneath the surface where the earthquake initiates.

• Richter Scale: Measures the magnitude (1-10) of an earthquake; a logarithmic scale.

• Earthquakes occurring underwater can trigger tsunamis.

Notable Devastating Earthquakes

• Indonesia, 2004:

  • Magnitude 9.1 earthquake off the coast of Indonesia, equivalent to releasing energy of approximately 23,000 atomic bombs.

  • Wave traveled 500 mph across the ocean and Banda Aceh was hit by a 100 ft tsunami about 15 minutes after the quake.

• Fukushima, Japan, 2011:

  • Magnitude 9.0 earthquake occurred, leading to a 130 ft tsunami.

  • Resulted in meltdown of 4 out of 6 nuclear reactors at a nearby plant, causing extensive evacuations (110,000 people) and an estimated 20,000 deaths.

  • Large releases of radioactive material into soil, sea, and air.

Recorded Path of Radioactive Material (Cesium-137) after Fukushima Meltdown

• Areas affected:

  • From Fukushima to the Arctic Ocean and Alaska.

Predicting Geological Activity using Tectonic Maps

• The Ring of Fire is a notable pattern of volcanoes around the Pacific plate, often associated with offshore island arcs (e.g., Japan).

• Transform faults are likely locations for earthquakes.

• Hotspots refer to areas of very hot magma rising to the surface (e.g., Mid-ocean Islands like Hawaii).

Hawaiian Islands Formation via Hotspot

• Age of islands varies:

  • Kauai: 3.8 to 5.6 million years old

  • Oahu: 2.2 to 3.4 million years

  • Molokai: 1.3 to 1.8 million years

  • Maui: 0.8 to 1.3 million years

  • Hawaii: 0.7 million years

• Direction of plate movement is towards the northwest.

Skills Practice

• Explain how subduction leads to volcanic activity.

Soil Formation & Erosion

Objectives, Essential Knowledge, and Skills

• Learning Objective (ERT-4.B)

  • Describe the characteristics and formation of soil.

• Suggested Skill (4.B)

  • Scientific Experiments: Identify a research method, design, and/or measure used.

• Essential Knowledge

  • ERT-4.B.1: Soils are formed when parent material is weathered, transported, and deposited.

  • ERT-4.B.2: Soils are categorized by horizons based on their composition and organic material.

  • ERT-4.B.3: Soils can be eroded by winds or water; protecting soils helps in maintaining water quality as soils filter and clean water moving through them.

Roles of Soil

• Plants: Stabilize soil by anchoring roots, and provide water, shelter, and nutrients (nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg)) for growth.

• Water: Filters rainwater and runoff by trapping pollutants in pore spaces and through plant roots; clean water enters groundwater and aquifers.

• Nutrient Recycling: Hosts decomposers that break down dead organic matter and return nutrients to the soil.

• Habitat: Provides habitat for organisms like earthworms, fungi, bacteria, moles, and slugs.

• Mix of Components: Soil consists of geologic (rock) and organic (living) components:

  • Sand, silt, clay

  • Humus: Main organic part of soil includes broken down biomass like leaves, dead animals, waste, etc.

  • Nutrients: Ammonium, phosphates, nitrates.

  • Water and air are also integral components of the soil ecosystem.

Weathering and Erosion

Weathering

• Definition: Breakdown of rocks into smaller pieces.

• Types of Weathering:

  • Physical: Wind, rain, freezing/thawing of ice.

  • Chemical: Acid rain, acids produced by moss/lichen.

  • Biological: Roots of trees cracking rocks.

• Weathering contributes to soil formation, breaking rocks into smaller fragments.

Erosion

• Definition: Transport of weathered rock fragments by wind and rain.

• Process: Eroded materials are carried to new locations, ultimately leading to deposition.

Soil Formation

• Weathering of parent material (bedrock) produces smaller fragments contributing to the geological/inorganic part of soil.

• Three classifications of soil:

  • Sand (largest particle size)

  • Silt

  • Clay (smallest particle size)

• Breakdown of organic matter adds humus to soil.

• Erosion contributes soil particles from other areas, continuously enhancing soil quality.

Parent Material (Bedrock)

• Weathering and erosion of bedrock leads to soil particle formation.

Effects on Soil Formation

1. Parent Material: Influences soil pH, nutrient content.

2. Topography:

   • Steep slopes lead to high erosion rates.

   • Level grounds promote higher deposition rates.

3. Climate:

   • Warmer temperatures increase decomposition rates.

   • More precipitation facilitates physical/chemical weathering and erosion processes.

4. Organisms:

   • Bacteria, fungi, and worms function as key decomposers, enhancing organic matter decomposition and nutrient recycling in soil. Higher activities of decomposers lead to faster soil formation rates.

Soil Horizons

• O-Horizon: Organic matter layer (plant roots, dead leaves, animal waste, etc.) on top of soil, providing nutrients and limiting water loss due to evaporation.

• A-Horizon: Known as topsoil; it contains humus (decomposed organic matter) and minerals from parent material. It has the highest biological activity for breaking down organic matter to release nutrients, taking 100-400 years to form 1 cm.

• B-Horizon: Referred to as subsoil; consists of lighter layers mostly comprising minerals with little to no organic matter and contains some nutrients.

• C-Horizon: Represents the least weathered soil closest to the parent material (bedrock).

Soil Degradation

• Definition: The loss of the soil's ability to support plant growth.

Causes of Soil Degradation

1. Loss of Topsoil: Caused by tilling for agriculture and loss of vegetation, leading to increased soil erosion by wind and rain. Loss of topsoil dries out soil and removes nutrients and vital organisms that recycle nutrients.

2. Nutrient Depletion: Continuous cropping reduces key nutrients (N, P, K, Na, Mg), undermining future crop productivity. Farmers may rotate crops to avoid nutrient depletion.

3. Compaction: Compression of soil by machinery (tractors, bulldozers), grazing livestock, and human activity reduces soil's moisture retention capability. Dry soils are prone to erosion and support fewer plants, exacerbating erosion processes.

Soil Composition & Properties

Objectives, Essential Knowledge, and Skills

• Learning Objective (ERT-4.C)

  • Describe similarities and differences between the properties of different soil types.

• Suggested Skill (4.C)

  • Scientific Experiments: Describe an aspect of a research method, design, and/or measure used.

• Essential Knowledge

  • ERT-4.C.1: The water holding capacity varies with different soil types, contributing to land productivity and fertility of soils.

  • ERT-4.C.2: Particle size and composition of each soil horizon can affect porosity, permeability, and fertility of the soil.

  • ERT-4.C.3: Variety of methods exist to test chemical, physical, and biological properties of soil, aiding in decisions about irrigation and fertilizer requirements.

  • ERT-4.C.4: A soil texture triangle is a diagram used for identifying and comparing soil types based on their percentages of clay, silt, and sand.

Soil Particle Size, Texture, and Porosity

• The geologic (rock) portion of soil is made up of three types of particles, ordered by size:

  • Sand (largest) > Silt > Clay (smallest)

• Soil Texture: The percentage composition of sand, silt, and clay in a soil always adds up to 100% (e.g., 40-40-20).

• Porosity: Refers to the amount of pore space a soil has; more sand increases porosity (better drainage), while more clay reduces porosity (poorer drainage).

Porosity, Permeability, and H2O Holding Capacity

• Porosity: Space within a soil allows for air and water entry, generally favoring sandy soils due to larger grains.

• Permeability: The measure of how easily water can drain through a soil. Higher porosity usually means higher permeability.

• H2O Holding Capacity: The ability of soil to retain water. A positive correlation exists between porosity and permeability. More porous/permeable soils usually have lower holding capacity; thus, ideal soils for most plants are loams, which balance porosity with water retention capabilities.

Soil Fertility

• Definition: The ability of soil to support plant growth.

• Nutrients: Essential elements include N, P, K, Mg, Ca, Na.

• Factors that increase soil nutrients:

  • Organic matter releases nutrients.

  • Humus retains and releases nutrients.

  • Active decomposer populations recycle nutrients.

• Factors that decrease soil nutrients:

  • Excessive rain/irrigation can leach nutrients away.

  • Intensive farming practices can strip nutrients from soil.

  • Loss of topsoil can lead to nutrient depletion.

Characteristics and Tests for Soil Quality

Practice FRQ 4.3

• Identify and describe one test that can be conducted on a soil sample. Explain how the results of the test could guide advice for a farmer trying to grow crops in that soil.

The Atmosphere

Objectives, Essential Knowledge, and Skills

• Learning Objective (ERT-4.D)

  • Describe the structure and composition of the Earth's atmosphere.

• Suggested Skill (Visual Representations, 2.A)

  • Describe characteristics of an environmental concept, process, or model represented visually.

• Essential Knowledge

  • ERT-4.D.1: The atmosphere is made up of major gases, each with its own relative abundance.

  • ERT-4.D.2: The layers of the atmosphere are defined based on temperature gradients: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.

Composition of Earth's Atmosphere

• Atmosphere mainly consists of gases:

  • Nitrogen (N2): ~78%, produced by photosynthesis in plants, necessary for respiration.

  • Oxygen (O2): ~21%, important for aerobic respiration.

  • Argon: ~0.93%, a noble gas.

  • Carbon Dioxide (CO2): ~0.04%, varies regionally, serves as a greenhouse gas but less significant than others.

  • Water Vapor: 0-4%, varies depending on conditions.

Atmospheric Layers

• Troposphere: 0-16 km; densest layer where weather occurs, contains most atmospheric gases; temperature decreases as altitude increases.

• Stratosphere: 16-60 km; contains the thickest ozone layer that absorbs harmful UV radiation; planes fly here, with increasing temperatures at higher altitudes due to UV absorption.

• Mesosphere: 60-80 km; coldest layer (-150°F); meteors burn up here; density is low.

• Thermosphere: 80-600 km; extremely high temperatures due to solar radiation absorption; where auroras (northern lights) occur.

• Exosphere: 600-10,000 km; transition space into outer space where satellites orbit.

Temperature Fluctuation in Atmospheric Layers

• Graph showing temperature change with altitude across atmospheric layers.

Practice FRQ 4.4

• Identify a layer of Earth from the diagram that has an inverse relationship between temperature and altitude. Describe why this occurs.

Global Wind Patterns

Objectives, Essential Knowledge, and Skills

• Learning Objective: Understand concepts of atmospheric circulation driven by various factors including the sun's energy, air density properties, and earth’s rotation (Coriolis effect).

• Rules of Air Movement:

  1. Warm moist air rises; cool dry air sinks; thus creating convection.

  2. Air moves from high-pressure areas to low-pressure areas.

  3. Winds are named based on the direction they originate from (e.g., westerly winds blow from the west towards the east).

Air Properties

• The sun's unequal heating of Earth drives wind cycles.

• Areas between 23.5°N (Tropic of Cancer) and 23.5°S (Tropic of Capricorn) receive the most direct sunlight, influencing temperature and pressure patterns.

Hadley Cell Formation

1. More direct sunlight at the equator warms air.

2. Warm air rises, cools and expands.

3. Cooling air spreads out, with dry, cold air sinking back down around 30°N & S, creating arid desert conditions.

Coriolis Effect

• Causes objects moving through the atmosphere to be deflected due to Earth’s rotation.

• Deflection: Right in the Northern Hemisphere, Left in the Southern Hemisphere.

Global Wind Patterns Diagram

• Visual representation of wind patterns and their effects across different latitudes.

Practice FRQ 4.5

• Explain how the sun is responsible for the pattern of air circulation seen in a specified cycle.

Watersheds

Objectives, Essential Knowledge, and Skills

• Learning Objective (ERT-4.F)

  • Describe the characteristics of a watershed.

• Keywords to Understand: Area, length, slope, soil, vegetation types, watershed divides.

• Suggested Skill (1.C): Explain environmental concepts in applied contexts.

Characteristics of Watersheds

• Defined as all land draining into a specific body of water (river, lake, bay, etc.).

• Determined by slope: ridges of high land divide watersheds affecting runoff directions.

• Vegetation, soil composition, and slope influence watershed drainage dynamics.

• Effects of human activities (agriculture, urbanization, mining) on watershed quality and water quality.

Watershed Terminology

1. Highest Points: Watershed Divide.

2. Tributary: A stream flowing into a larger river.

3. River/Deltas: River mouths where waters meet the sea.

Chesapeake Bay Watershed

• Involves a six-state region draining into a series of rivers and streams.

• Estuaries and wetlands in the Chesapeake Bay provide ecosystem services such as tourism, nutrient filtration, and natural disaster buffering.

• Nutrient pollution (N & P) impacts the bay, leading to issues like eutrophication.

• Major sources of nutrient pollution include sewage discharge, animal waste, and synthetic fertilizers.

Human Impacts on Watersheds

1. Soil Erosion: Loss of stabilizing roots leads to sedimentation in local streams.

2. Increased temperatures: Loss of tree cover raises soil and stream temperatures, negatively affecting aquatic habitats.

3. Damming: Regulates water flow, leading to nutrient flow restriction, increased water temperatures, and disrupted aquatic ecosystems.

4. Pollutants: Metals and endocrine disruptors impact organisms and ecosystem health.

Solutions to Watershed Pollution

• Riparian buffers, nutrient management, use of cover crops, and septic tank upgrades can enhance watershed quality by reducing nutrient runoff and improving water quality.

Practice FRQ 4.6

• Identify one change in water quality that occurs in streams due to deforestation within a watershed and explain how this change occurs.

Solar Radiation & Earth's Seasons

Objectives, Essential Knowledge, and Skills

• Learning Objective (ENG-2.A): Explain how solar energy affects the Earth's surface.

• Suggested Skill (Visual Representations, 2.A): Describe characteristics of these processes visually represented.

• Essential Knowledge

  • ENG-2.A.1: Incoming solar radiation (insolation) is dependent on seasons and latitude.

  • ENG-2.A.2: The sun's rays' angle affects insolation intensity.

  • ENG-2.A.3: Highest insolation is received at the equator, decreasing toward the poles.

  • ENG-2.A.4: Solar radiation varies seasonally, with the most received on the longest summer day.

  • ENG-2.A.5: Earth's axial tilt causes seasonal changes in daylight hours.

Solar Intensity & Latitude

• Insolation (W/m²) depends on: angle and the atmosphere's density affecting solar rays.

• The equatorial region receives higher insolation than higher latitudes.

Solar Intensity & Season

• Earth's orbit and axis tilt change the angle of solar exposure, affecting variations in insolation, sunlight duration, and seasonal weather patterns.

Summary of Seasonal Changes

1. June Solstice: Most direct sunlight at Tropic of Cancer (23.5° N).

2. December Solstice: Direct sunlight peaks at Tropic of Capricorn (23.5° S).

3. Equinoxes: Equal sunlight distribution between both hemispheres during March and September.

Albedo

• Definition: The proportion of light reflected by a surface.

• High albedo surfaces (ice, snow) reflect more light; low albedo surfaces (water, urban areas) absorb more light, leading to temperature increases.

Albedo & Climate Change

• Higher atmospheric CO2 concentrations enhance heat retention, causing polar ice melting.

• Lowered albedo increases heat retention, leading to further global warming.

Practice FRQ 4.7

• Identify which season is occurring in the Northern Hemisphere from the provided diagram and explain how the tilt of Earth’s axis influences this phenomenon.

Earth's Geography & Climate

Objectives, Essential Knowledge, and Skills

• Learning Objective (ENG-2.B): Describe how Earth's geography affects weather and climate.

• Essential Knowledge

  • ENG-2.B.1: Weather and climate are influenced by sunlight energy and geologic/geographic factors like mountains and ocean temperatures.

  • ENG-2.B.2: A rain shadow is created when higher elevation areas block precipitation from reaching lower altitudes.

Geography's Influence on Climate

• Climate is primarily determined by insolation affected by latitude and the atmosphere.

• Geography also impacts microclimates, with mountains disrupting wind patterns and oceans moderating temperatures and moisture levels.

Rain Shadow Effect

• Warm moist air ascends the windward side of mountains, cools, and produces rainfall, resulting in lush vegetation.

• Descending dry air on the leeward side can create arid conditions, exemplified by regions prone to deserts.

Example: Andes Mountains

• Windward (eastern) side experiences significant rainfall due to trade winds carrying moisture from the Atlantic Ocean.

• Leeward (western) side experiences dry conditions leading to desert formations like the Atacama Desert.

El Nino & La Nina

Objectives, Essential Knowledge, and Skills

• Learning Objective (ENG-2.C): Describe environmental changes due to El Niño and La Niña events.

• Suggested Skill (7.A): Describe environmental problems.

• Essential Knowledge

  • ENG-2.C.1: El Niño and La Niña relate to changes in ocean surface temperatures impacting global weather patterns.

  • ENG-2.C.2: These phenomena are influenced by geological and geographic factors.

Global Ocean Surface Currents

• Gyers: Form large circular patterns due to global wind and the Coriolis effect.

• Upwelling Zones: Areas where winds remove warm surface water, allowing colder nutrient-rich water to surface. This phenomenon promotes fishery productivity.

El Niño Southern Oscillation (ENSO)

• ENSO: Shifting atmospheric pressure and ocean currents between South America and Australia/Southeast Asia.

  • Normal Conditions: Trade winds blow warm water east to west; leads to cooler, nutrient-rich waters off the coast of South America.

  • During El Niño: Weak trade winds reverse; warm waters bring rain and heat to the Americas, suppressing upwelling.

  • During La Niña: Trade winds strengthen, enhancing upwelling along the coast, providing cold nutrient-rich waters conducive to better fishing conditions.

Key Environmental Effects

1. El Niño (Warm waters):

   • Poor fishing conditions due to lower oxygen and nutrient levels, warm winters in North America, flooding.

2. La Niña (Cold waters):

   • Increased fishery productivity, cooler and drier conditions in the Americas, heightened tornado activity.

Practice FRQ 4.9

• Describe two environmental problems associated with El Niño events.