Unit 4 Summary: Earth Systems and Resources 4.1 Plate Tectonics st each other → earthquakes. 4.2 Soil Formation and Erosion • Soil Formation: Weather

What causes earthquakes at plate boundaries?

Plates pushing against each other.

O-Horizon

Layer of soil rich in organic matter.

What is the top layer of soil called?

A-Horizon or Topsoil, rich in nutrients for plants.

Soil Degradation

The decline in soil quality due to loss of topsoil, compaction, and nutrient depletion.

What are the main components of soil?

Sand, silt, clay, humus, water, air, and organisms.

Texture of soil

Relates to the size of soil particles, such as sand (big) and clay (small).

Permeability of sand and clay

Sand has high permeability, while clay has low permeability.

Greenhouse Gases

Gases like CO₂, water vapor, and methane that trap heat in the atmosphere.

What happens in the Troposphere?

Weather occurs in this layer of the atmosphere.

Hadley Cell

Wind cell that causes air to rise at the equator and sink at 30°, creating rain and deserts.

What effect does Earth's rotation have on wind?

The Coriolis Effect curves winds.

Watershed

Land area where water drains into a single point.

How do trees affect watersheds?

Vegetation reduces runoff and erosion.

What is Earth's tilt and its significance?

Earth's tilt of 23.5° causes seasons by changing sunlight angles.

Albedo effect

Ice reflects sunlight (cooling), while dark surfaces absorb it (warming).

El Niño effects

Weak trade winds allow warm water to stay near the Americas, causing rain in Americas and drought in Asia.

La Niña effects

Strong trade winds lead to cold water upwelling, causing dry conditions in the Americas and wet conditions in Asia.

What are rain shadows?

Areas where the windward side is wet and green, while the leeward side is dry and desert-like.

Key takeaway about Earth's systems

Earth’s systems including plates, wind, water, and soil are interconnected.