AP Environmental Science Unit 4 Cheatsheet: Earth Systems and Resources

Convergent: Plates collide → mountains, island arcs, earthquakes, volcanoes

Divergent: Plates separate → seafloor spreading, rift valleys, earthquakes, volcanoes

Transform: Plates slide past each other → earthquakes only

Earthquake mechanism: Stress builds at locked fault → overcomes friction → stored energy releases suddenly

Map use: Global plate boundary maps help predict the locations of many volcanoes, island arcs, earthquakes, and major faults; hot spots often occur within plate interiors.

Major gases: Each has distinct relative abundance (N₂, O₂, Ar, CO₂, etc.).

Five layers by temperature gradient:

• Troposphere (lowest, where weather occurs)
• Stratosphere (contains ozone)
• Mesosphere
• Thermosphere
• Exosphere (outermost)

Temperature changes define layer boundaries.

Convergent vs. divergent: Convergent = collision (mountains, arcs); divergent = separation (spreading, rifts). Both can cause earthquakes and volcanoes.

Loam ≠ clay: Loam is balanced; clay is one extreme (high water retention, low permeability).

Insolation ≠ temperature: High insolation doesn't always mean high temperature (depends on atmosphere, surface, season).

Rain shadow: Occurs on leeward (downwind) side, not windward.

Strategy: Use maps, diagrams, and data tables to support descriptions and explanations. Connect processes to real-world outcomes.