APES unit 4

What is a convergent plate boundary?

A boundary where two plates move toward each other.

How do convergent boundaries form mountains?

Continental–continental convergence pushes crust upward.

How do convergent boundaries form volcanoes?

Oceanic–continental convergence causes subduction → melting → magma rises.

What is a divergent plate boundary?

A boundary where two plates move away from each other.

Where do divergent boundaries occur most commonly?

Mid-ocean ridges.

What landforms do divergent boundaries create?

Seafloor spreading, rift valleys, mid-ocean ridges.

What causes plates to move apart at divergent boundaries?

Rising convection currents in the mantle.

What is a transform boundary?

A boundary where plates slide past one another horizontally.

How do transform boundaries create earthquakes?

Friction builds stress → sudden release causes shaking.

How can plate boundary maps predict volcanoes, earthquakes, and island arcs?

These hazards cluster along active boundaries (subduction zones, faults, ridges).

What is the Ring of Fire?

A tectonically active zone around the Pacific with many volcanoes and earthquakes.

Why does the Ring of Fire occur?

Multiple subduction zones around the Pacific Plate.

What is parent material?

The underlying rock that soil forms from.

What are the two types of weathering?

Physical (mechanical) and chemical weathering.

How does physical weathering form soil?

Breaks rock into smaller pieces.

How does chemical weathering form soil?

Reacts with rock to change minerals and create new soil components.

List and describe the four soil horizons.

O horizon: Organic litter; A horizon: Topsoil, humus + minerals; B horizon: Subsoil, mineral accumulation; C horizon: Partially weathered parent material.

Why is organic matter important in soil?

Increases fertility, water retention, and supports microbes.

Name four ecosystem services soil provides.

Habitat, nutrient cycling, water filtration, plant growth support.

How does soil filter groundwater?

Pores trap pollutants; microbes break down contaminants.

Rank soil particles from largest → smallest.

Sand → silt → clay.

How does size relate to porosity?

Larger particles = higher porosity.

How does texture relate to water-holding capacity?

More clay = higher water holding; more sand = low holding.

How does water-holding capacity affect plant growth?

Too much water = poor aeration; too little = drought stress.

Identify two chemical measures of soil quality.

pH and NPK nutrient levels.

How does soil pH affect plant growth?

Controls nutrient availability.

What is the soil type with 30% sand, 40% silt, 30% clay?

Loam.

Describe the temperature gradient of the atmosphere.

Troposphere: Temp decreases with altitude; Stratosphere: Temp increases (ozone absorbs UV); Mesosphere: Temp decreases; Thermosphere: Temp increases; Exosphere: Very thin; temp variable.

What gases make up Earth’s atmosphere?

78% nitrogen, 21% oxygen, 0.9% argon, 0.1% other gases.

Describe the five layers of Earth’s atmosphere.

Troposphere: Weather occurs; Stratosphere: Ozone layer; Mesosphere: Meteors burn; Thermosphere: Auroras; Exosphere: Transition to space.

What are the basic steps of Hadley cells?

Warm air rises at equator → cools → sinks at 30° → returns as trade winds.

Why do deserts form at 30° N/S?

Descending dry air suppresses rainfall.

Why is there heavy rain near the equator?

Rising warm humid air condenses.

Where is solar radiation most direct?

At the equator.

Direction of winds:

0–30°: Trade winds blow east → west; 30–60°: Westerlies blow west → east; 60–90°: Polar easterlies blow east → west.

How does the Coriolis effect shape wind patterns?

Rotation deflects air right in N hemisphere, left in S hemisphere.

What is a watershed?

Land area that drains into a body of water.

Name two human activities that impact watersheds and their effects.

Agriculture → fertilizer runoff → eutrophication; Urbanization → increased runoff → flooding.

Why must urban planners consider watershed boundaries?

Structures affect drainage, flooding, pollution pathways.

How does Earth’s orbit affect solar intensity?

Distance & angle determine how concentrated sunlight is.

How does Earth’s tilt cause seasons?

Tilt changes sunlight angle & day length.

Define insolation.

Incoming solar radiation.

How does sun angle affect intensity?

Higher angle = more concentrated energy.

What is the relationship between latitude and solar intensity?

Higher latitude = lower intensity.

What is a rain shadow?

Windward side gets moist air & rain; leeward side is dry.

How does rain shadow affect vegetation?

Windward = lush forests; leeward = deserts.

What is the relationship between the rain shadow and the Andes region?

Andes block moisture → Atacama Desert forms on leeward side.

How do mountains affect microclimates?

Elevation changes temperature, precipitation, wind.

How do ocean temperatures affect climate?

Warm currents heat coasts; cold currents cool and dry coasts.

What is the impact of El Niño on South American fisheries?

Warm water suppresses upwelling → fish populations crash.

What is the impact of El Niño on South American weather?

Heavy rainfall, flooding.

What is the impact of El Niño on North American west coast?

Warmer, wetter winters.

What is the impact of El Niño on Southeast Asia?

Drought and wildfires.

What are the steps of El Niño formation?

Weakened trade winds → warm water moves east → reduced upwelling → global weather shifts.

What are the steps of La Niña formation?

Strengthened trade winds → more cold upwelling → exaggerated normal patterns → wetter SE Asia, drier Americas.