AP Environmental Science - Unit 2 Review

Introduction

• Review of Unit 2 for AP Environmental Science.
• Importance of practicing writing style for the exam.
• Encourages use of mini-FRQs for practice.

Biodiversity

Levels of Biodiversity

1. Genetic Biodiversity
   • Variance in genes within individuals of a population.
   • High genetic diversity increases adaptability to environmental disturbances.
2. Species Biodiversity
   • Diversity of different types of organisms in an ecosystem.
   • Species Richness: Total number of different species.
   • Species Evenness: Balance of population sizes; crucial for ecosystem stability.
3. Ecosystem Biodiversity
   • Variance in different ecosystems within an area.
   • High diversity in ecosystems supports greater species richness.

Benefits of Biodiversity

• Genetic diversity benefits populations by enhancing adaptability.
• Species diversity supports ecosystem resilience.
• Ecosystem diversity benefits entire biomes.

Ecosystem Services

• Provisioning Services: Direct products from ecosystems (e.g., wood).
• Supporting Services: Ecosystem processes that support human activities (e.g., pollination).
• Regulating Services: Ecosystems stabilize climate conditions (e.g., carbon sequestration).
• Cultural Services: Recreational and intellectual benefits from nature.

Disruption of Ecosystem Services

• Example: Deepwater Horizon oil spill affected multiple ecosystem services including fishing, coastal stability, and tourism.

Island Biogeography

Key Concepts

• Distance from Mainland: Closer islands have higher species richness due to ease of migration.
• Island Size: Larger islands support more species due to greater habitat diversity.
• Specialist Species: Islands have more specialist species, vulnerable to invasive species (e.g., dodo bird).

Ecological Tolerance

• Range of conditions organisms can tolerate.
• Examples of zones: Optimal range, zone of physiological stress, zone of intolerance.
• Importance of genetic diversity in providing a buffer against environmental changes.

Natural Disruptions to Ecosystems

Types of Events

• Periodic: Regular events (e.g., rainy seasons).
• Episodic: Less frequent, yet regular (e.g., hurricanes).
• Random: Unpredictable events (e.g., volcanic eruptions).
• Gradual Climate Change: Natural changes due to Earth's orbital cycles (Milankovitch cycles).

Adaptation and Extinction

• Adaptations arise from genetic diversity and environmental pressures.
• Environmental changes can lead to new adaptations or extinction.

Ecological Succession

Types of Succession

1. Primary Succession: Begins on bare rock; pioneer species like moss and lichen initiate soil development.
2. Secondary Succession: Begins on disturbed soil; faster as soil already exists.

Keystone Species

• Keystone species have a crucial role in ecosystem function (e.g., wolves, beavers).

Conclusion

• Importance of understanding and preserving biodiversity and ecosystem services.
• Think and write like a scholar for exams.

Remember to leverage these key concepts and examples as a foundation for AP Environmental Science studies.