AP Environmental Science Unit 2 Review

Introduction

• Focus on understanding key concepts of biodiversity and ecosystem services.
• Importance of practicing writing style for the AP exam using mini FRQs.

Biodiversity

• Definition: Diversity of different life forms in an ecosystem.
• Three Levels of Biodiversity:
  • Genetic Biodiversity:
    • Variance in genes within a population.
    • High genetic diversity allows adaptation to environmental changes.
  • Species Diversity:
    • Diversity of different organisms in an ecosystem.
    • Species Richness: Total count of different species.
    • Species Evenness: Balance of population sizes of different species.
  • Ecosystem Biodiversity:
    • Variance in ecosystems within a biome.
    • High ecosystem diversity supports greater species richness.

Ecosystem Services

• Types of Ecosystem Services:
  • Provisioning Services: Direct products from ecosystems (e.g., wood).
  • Supporting Services: Ecosystem processes that support human activities (e.g., pollination).
  • Regulating Services: Stabilize climate and environmental factors (e.g., carbon sequestration).
  • Cultural Services: Recreational and intellectual benefits from nature.
• Human Disruption: Example of oil spills disrupting services.

Theory of Island Biogeography

• Concepts:
  • Islands closer to the mainland have higher species richness.
  • Larger islands support more species due to higher ecosystem diversity.
• Specialist Species:
  • Unique adaptations to island environments.
  • Vulnerable to invasive species.

Ecological Tolerance

• Definition: Range of conditions a species can tolerate.
• Zones of Tolerance:
  • Optimal Range: Best conditions for survival and reproduction.
  • Zone of Physiological Stress: Reduced functioning.
  • Zone of Intolerance: Conditions leading to death.
• Importance of Genetic Diversity: Acts as a buffer against environmental changes.

Natural Events and Ecosystem Disturbances

• Types of Events:
  • Periodic Events: Occur regularly (e.g., rainy seasons).
  • Episodic Events: Occur less regularly when conditions are right (e.g., hurricanes).
  • Random Events: Occur with no regularity (e.g., asteroid strikes).
• Climate Change:
  • Natural changes in Earth's orbit affect climate over tens of thousands of years.
  • Impacts on sea levels and ecosystems.

Adaptations

• Process: Organisms adapt to environmental changes or face extinction.
• Example: Homo habilis and opposable thumbs.

Ecological Succession

• Primary Succession:
  • Colonization of bare rock by pioneer species.
  • Formation of soil and subsequent colonization by other species.
• Secondary Succession:
  • Disturbed soil colonized by pioneer species (e.g., after a forest fire).

Keystone Species

• Definition: Species critical to ecosystem function.
• Examples: Wolves, beavers, and mangroves.

Conclusion

• Emphasized understanding of vocabulary and concepts.
• Encouraged further study and practice of key ideas.