AP Environmental Science Unit 2 Review

Introduction

• Speaker: Mr. Smeads
• Purpose: Review of Unit 2 from the AP Environmental Science course.
• Key Advice:
  • Have the Ultimate Review Packet study guide ready.
  • Practice the writing style required for AP exams using mini FRQs at the end of each unit.

Biodiversity

Understanding Biodiversity

• Definition: Diversity of different life forms in an ecosystem.
• Three Levels of Biodiversity:
  1. Genetic Biodiversity: Variance of genes within a population.
     • Benefits: Increases adaptability to environmental changes.
  2. Species Biodiversity: Diversity of different species in an ecosystem.
     • Measured by:
       • Species Richness: Total count of species.
       • Species Evenness: Distribution of population sizes.
  3. Ecosystem Biodiversity: Variation of ecosystems in a given area.
     • Example: High in tropical rainforests, low in deserts.

Importance of Biodiversity

• Genetic Diversity: Acts as a buffer against environmental disturbances.
• Species Diversity: Keeps ecosystem stable against diseases.
• Ecosystem Diversity: Supports a wide variety of species.

Ecosystem Services

Types of Ecosystem Services

1. Provisioning Services
   • Direct products from ecosystems, e.g., wood.
2. Supporting Services
   • Processes that support human actions, e.g., pollination.
3. Regulating Services
   • Regulation of climate/environmental factors.
4. Cultural Services
   • Recreational/intellectual benefits from nature.

Human Disruption

• Examples: Oil spills affecting fisheries, coastlines, and tourism.

Island Biogeography

• Theory: Describes species richness on islands.
• Factors:
  • Distance from Mainland: Closer islands have higher species richness.
  • Island Size: Larger islands support more species.
• Adaptations: Islands often have specialist species vulnerable to invasives.

Ecological Tolerance

• Definition: Range of conditions a species can tolerate.
• Zones:
  • Optimal Range: Conditions where species thrive.
  • Zone of Physiological Stress: Reduced function.
  • Zone of Intolerance: Leads to death.

Natural Disruptions to Ecosystems

• Types:
  • Periodic: Regular events like rainy seasons.
  • Episodic: Less regular but patterned, e.g., hurricanes.
  • Random: Unpredictable, e.g., asteroid impacts.

Climate Change and Earth’s Orbit

• Milankovitch Cycles: Changes in Earth’s orbit leading to natural climate variations.
• Impacts: Changes in sea level affecting ecosystems like estuaries.

Adaptation and Survival

• Genetic Diversity: Essential for adaptation.
• Examples: Opposable thumbs in Homo habilis providing an evolutionary advantage.

Ecological Succession

• Types:
  • Primary Succession: Begins on bare rock, involves pioneer species like moss.
  • Secondary Succession: Begins on soil after a disturbance.
• Keystone Species: Vital for ecosystem stability.
  • Examples: Wolves, beavers, and mangroves.

Conclusion

• Wrap-Up: Encouragement to think critically and write effectively.
• Goals: Understand and apply the vocabulary and concepts of Unit 2 effectively.