APES unit 4
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APES Unit 4 – Flashcard-Ready Study Guide
Formatted as Q = front / A = back.
4.1 Plate Tectonics
Q: What is a convergent plate boundary?
A: A boundary where two plates move toward each other.
Q: How do convergent boundaries form mountains?
A: Continental–continental convergence pushes crust upward.
Q: How do convergent boundaries form volcanoes?
A: Oceanic–continental convergence causes subduction → melting → magma rises.
Q: What is a divergent plate boundary?
A: A boundary where two plates move away from each other.
Q: Where do divergent boundaries occur most commonly?
A: Mid-ocean ridges.
Q: What landforms do divergent boundaries create?
A: Seafloor spreading, rift valleys, mid-ocean ridges.
Q: What causes plates to move apart at divergent boundaries?
A: Rising convection currents in the mantle.
Q: What is a transform boundary?
A: A boundary where plates slide past one another horizontally.
Q: How do transform boundaries create earthquakes?
A: Friction builds stress → sudden release causes shaking.
Q: How can plate boundary maps predict volcanoes, earthquakes, and island arcs?
A: These hazards cluster along active boundaries (subduction zones, faults, ridges).
Q: What is the Ring of Fire?
A: A tectonically active zone around the Pacific with many volcanoes and earthquakes.
Q: Why does the Ring of Fire occur?
A: Multiple subduction zones around the Pacific Plate.
4.2 Soil Formation & Erosion
Q: What is parent material?
A: The underlying rock that soil forms from.
Q: What are the two types of weathering?
A: Physical (mechanical) and chemical weathering.
Q: How does physical weathering form soil?
A: Breaks rock into smaller pieces.
Q: How does chemical weathering form soil?
A: Reacts with rock to change minerals and create new soil components.
Q: List and describe the four soil horizons.
A:
O horizon: Organic litter.
A horizon: Topsoil, humus + minerals.
B horizon: Subsoil, mineral accumulation.
C horizon: Partially weathered parent material.
Q: Why is organic matter important in soil?
A: Increases fertility, water retention, and supports microbes.
Q: Name four ecosystem services soil provides.
A: Habitat, nutrient cycling, water filtration, plant growth support.
Q: How does soil filter groundwater?
A: Pores trap pollutants; microbes break down contaminants.
4.3 Soil Properties
Q: Rank soil particles from largest → smallest.
A: Sand → silt → clay.
Q: How does size relate to porosity?
A: Larger particles = higher porosity.
Q: How does texture relate to water-holding capacity?
A: More clay = higher water holding; more sand = low holding.
Q: How does water-holding capacity affect plant growth?
A: Too much water = poor aeration; too little = drought stress.
Q: Identify two chemical measures of soil quality.
A: pH and NPK nutrient levels.
Q: How does soil pH affect plant growth?
A: Controls nutrient availability.
Q: What is the soil type with 30% sand, 40% silt, 30% clay?
A: Loam.
4.4 Earth’s Atmosphere
Q: Describe the temperature gradient of the atmosphere.
A:
Troposphere: Temp decreases with altitude
Stratosphere: Temp increases (ozone absorbs UV)
Mesosphere: Temp decreases
Thermosphere: Temp increases
Exosphere: Very thin; temp variable
Q: What gases make up Earth’s atmosphere?
A: 78% nitrogen, 21% oxygen, 0.9% argon, 0.1% other gases.
Q: Describe the five layers of Earth’s atmosphere.
A:
Troposphere: Weather occurs
Stratosphere: Ozone layer
Mesosphere: Meteors burn
Thermosphere: Auroras
Exosphere: Transition to space
4.5 Global Wind Patterns
Q: Basic steps of Hadley cells?
A: Warm air rises at equator → cools → sinks at 30° → returns as trade winds.
Q: Why do deserts form at 30° N/S?
A: Descending dry air suppresses rainfall.
Q: Why is there heavy rain near the equator?
A: Rising warm humid air condenses.
Q: Where is solar radiation most direct?
A: At the equator.
Q: Direction of winds:
A:
0–30°: Trade winds blow east → west
30–60°: Westerlies blow west → east
60–90°: Polar easterlies blow east → west
Q: How does the Coriolis effect shape wind patterns?
A: Rotation deflects air right in N hemisphere, left in S hemisphere.
4.6 Watersheds
Q: What is a watershed?
A: Land area that drains into a body of water.
Q: Two human activities that impact watersheds + effects:
A:
Agriculture → fertilizer runoff → eutrophication
Urbanization → increased runoff → flooding
Q: Why must urban planners consider watershed boundaries?
A: Structures affect drainage, flooding, pollution pathways.
4.7 Solar Radiation & Seasons
Q: How does Earth’s orbit affect solar intensity?
A: Distance & angle determine how concentrated sunlight is.
Q: How does Earth’s tilt cause seasons?
A: Tilt changes sunlight angle & day length.
Q: Define insolation.
A: Incoming solar radiation.
Q: How does sun angle affect intensity?
A: Higher angle = more concentrated energy.
Q: Relationship between latitude and solar intensity?
A: Higher latitude = lower intensity.
4.8 Geography & Climate
Q: What is a rain shadow?
A: Windward side gets moist air & rain; leeward side is dry.
Q: How does rain shadow affect vegetation?
A: Windward = lush forests; leeward = deserts.
Q: Rain shadow & Andes region?
A: Andes block moisture → Atacama Desert forms on leeward side.
Q: How do mountains affect microclimates?
A: Elevation changes temperature, precipitation, wind.
Q: How do ocean temperatures affect climate?
A: Warm currents heat coasts; cold currents cool and dry coasts.
4.9 El Niño & La Niña
Q: Impact of El Niño on South American fisheries?
A: Warm water suppresses upwelling → fish populations crash.
Q: Impact of El Niño on South American weather?
A: Heavy rainfall, flooding.
Q: Impact of El Niño on North American west coast?
A: Warmer, wetter winters.
Q: Impact of El Niño on Southeast Asia?
A: Drought and wildfires.
Q: Steps of El Niño formation?
A: Weakened trade winds → warm water moves east → reduced upwelling → global weather shifts.
Q: Steps of La Niña formation?
A: Strengthened trade winds → more cold upwelling → exaggerated normal patterns → wetter SE Asia, drier Americas.