AP Environmental Science Unit 1 Review

Introduction

• Focus on preparing for AP Environmental Science exams.
• Emphasis on the importance of Free Response Questions (FRQs) for earning college credit.
• Use the Unit 1 Ultimate Review Packet for study guides, practice questions, and exams.

Ecosystems Overview

• Ecosystem: Interaction of living and non-living things in a specific region.
• Environment: The entire natural world.
• Habitat: Environmental conditions needed by a species for survival.
• Species interactions:
  • Symbiosis: Close proximity living, not necessarily mutualistic.
  • Mutualism: Both species benefit.
• Examples:
  • Mutualism: Bees & plants, Coral reefs & algae.

Biomes

• Biome: Region with consistent yearly temperature and precipitation patterns.
• Examples: Tropical rainforest (high temp & precipitation), Tundra (low temp & precipitation).
• Climate change can cause biome shifts.
• Aquatic Biomes: Influenced by salinity, flow, and depth.
  • Example: Estuaries (brackish water, high nutrient productivity).

Biogeochemical Cycles

• Law of Conservation of Matter: Matter changes forms, is not created or destroyed.

Carbon Cycle

• Reservoirs: Temporary storage of matter.
• Sources: Processes moving matter between reservoirs.
• Sinks: Reservoirs taking in more matter than they emit.
• Important processes:
  • Photosynthesis: Plants take in carbon.
  • Respiration: Returns carbon to the atmosphere.
  • Combustion: Adds carbon from fossil fuels to the atmosphere.

Nitrogen Cycle

• Fast cycling compared to carbon.
• Nitrogen in the atmosphere is biologically unavailable.
• Nitrogen Fixation: Converts unusable nitrogen to ammonia or nitrate.
  • Main agents: Bacteria and human activities (e.g., combustion).

Phosphorus Cycle

• No atmospheric phase, cycles slowly through rock weathering.
• Weathering & Erosion: Release phosphates from rocks.
• Phosphorus is often a limiting nutrient.

Water Cycle

• Driven by solar energy.
• Key processes: Evaporation, Condensation, Infiltration, Transpiration.
• Major reservoir: Oceans (not usable for drinking or agriculture).

Energy Flow in Ecosystems

Primary Productivity

• Rate of photosynthesis in a given area.
• Gross Primary Productivity: Total energy produced.
• Net Primary Productivity: Energy stored after respiration losses.
• Calculation: NPP = GPP - Respiration Loss.

Trophic Levels & Energy Transfer

• Trophic Pyramid: Represents energy flow.
  • Producers at the base, followed by primary, secondary, tertiary consumers.
• 10% Rule: Only 10% of energy transfers to the next level, 90% is lost.

Food Webs & Chains

• Arrows indicate energy and matter transfer direction.
• Removal of species affects ecosystem balance (Trophic Cascades).

Conclusion

• Unit 1 covers crucial concepts for understanding ecosystems in AP Environmental Science.
• Use the Ultimate Review Packet for comprehensive study and practice.
• Practice, review, and understand key processes and cycles in ecosystems to excel in exams.