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AP Environmental Science Study Guide

1. Introduction to AP Environmental Science

AP Environmental Science (APES) covers a wide range of environmental topics, including ecology, energy resources, pollution, climate change, and sustainability. The course integrates knowledge from biology, chemistry, physics, and geography, with a focus on understanding the interactions between humans and the environment.

Exam Format:

  • Multiple-choice questions: Test your knowledge of environmental concepts, including problem-solving and analysis of case studies.
  • Free-response questions: Focus on applying your knowledge to real-world environmental issues, designing solutions, and interpreting data.

2. Earth Systems and Resources

Earth’s Layers:

  • Crust: The Earth's outermost layer, consisting of the lithosphere.
  • Mantle: The thick layer beneath the crust, made of semi-solid rock.
  • Core: The innermost layer, made up of a solid inner core and a liquid outer core.

Plate Tectonics:

  • Plate Boundaries: The edges where tectonic plates meet.
    • Divergent Boundaries: Plates move away from each other (e.g., Mid-Atlantic Ridge).
    • Convergent Boundaries: Plates move toward each other (e.g., Himalayas).
    • Transform Boundaries: Plates slide past each other (e.g., San Andreas Fault).

Soil Formation and Composition:

  • Soil Layers (Horizon): O (organic), A (topsoil), E (eluviation), B (subsoil), C (parent material), R (bedrock).
  • Soil Types: Sandy soils drain quickly, clay soils retain water, loam is ideal for farming.

Water Resources:

  • Water Cycle: Evaporation, condensation, precipitation, infiltration, and transpiration.
  • Freshwater Availability: Less than 3% of Earth's water is freshwater.
  • Water Scarcity: Occurs due to uneven distribution, pollution, and overuse.

3. Ecosystems and Biodiversity

Biomes:

  • Tropical Rainforests: High biodiversity, high rainfall, and year-round warmth.
  • Deserts: Low biodiversity, extreme temperature fluctuations, and low precipitation.
  • Grasslands: Found in temperate regions with moderate rainfall, supporting grasses and herbivores.
  • Temperate Forests: Deciduous trees and moderate precipitation.
  • Tundra: Cold, low precipitation, with a short growing season.

Ecological Concepts:

  • Food Chains and Webs: Flow of energy from producers to consumers.
    • Producers (Autotrophs): Plants and algae that make their own food.
    • Consumers (Heterotrophs): Organisms that consume other organisms for energy (herbivores, carnivores, omnivores).
  • Trophic Levels: Each step in the food chain/web.
  • Energy Flow: Only 10% of energy is transferred to each trophic level; the rest is lost as heat.

Biodiversity:

  • Genetic Diversity: The variation in genes within a species.
  • Species Diversity: The variety of different species in an ecosystem.
  • Ecosystem Diversity: The variety of ecosystems on Earth.
  • Endangered Species: Species at risk of extinction due to habitat loss, pollution, or overexploitation.

Ecological Succession:

  • Primary Succession: The development of an ecosystem in a previously uninhabited area (e.g., after a volcanic eruption).
  • Secondary Succession: The re-establishment of an ecosystem after a disturbance (e.g., forest after a fire).

4. Population Dynamics

Population Growth:

  • Exponential Growth: J-shaped curve; population grows at a constant rate.
  • Logistic Growth: S-shaped curve; population growth slows as resources become limited.

Carrying Capacity (K):

  • The maximum population size that an environment can support without degradation of resources.

Survivorship Curves:

  • Type I: High survival rate in early and middle life, with a decline in older age (e.g., humans).
  • Type II: Constant mortality rate throughout life (e.g., birds).
  • Type III: High mortality in early life, but those that survive live longer (e.g., oysters).

Demographic Transition:

  • Stage 1: High birth and death rates, resulting in slow population growth.
  • Stage 2: High birth rates, but death rates begin to fall, resulting in rapid growth.
  • Stage 3: Birth rates begin to fall, leading to slower growth.
  • Stage 4: Low birth and death rates, stabilizing the population.

5. Land and Water Use

Agriculture:

  • Industrial Agriculture: Large-scale farming with high input of fertilizers, pesticides, and machinery.
  • Sustainable Agriculture: Focuses on maintaining soil health, minimizing environmental impact, and supporting local communities.

Deforestation:

  • Causes include agriculture, logging, and urban development.
  • Leads to loss of biodiversity, disruption of water cycles, and increased CO₂ emissions.

Urbanization:

  • The growth of cities, leading to habitat destruction, air and water pollution, and increased resource consumption.

Water Use:

  • Irrigation: Can deplete groundwater and harm ecosystems.
  • Aquifers: Underground reservoirs of water, often over-exploited for agricultural and municipal use.
  • Water Pollution: Includes agricultural runoff, sewage, industrial discharge, and oil spills.

6. Energy Resources and Consumption

Renewable Energy:

  • Solar: Harnesses energy from the sun.
  • Wind: Uses wind turbines to generate electricity.
  • Hydropower: Uses water flow to generate electricity.
  • Geothermal: Uses heat from within the Earth.
  • Biomass: Organic material used for fuel (e.g., wood, crops).

Nonrenewable Energy:

  • Fossil Fuels: Coal, oil, and natural gas, which release CO₂ when burned, contributing to climate change.
  • Nuclear Power: Uses uranium to produce electricity, with radioactive waste as a byproduct.

Energy Conservation:

  • Increasing energy efficiency and reducing consumption through improved technology, behavior changes, and alternative energy sources.

7. Pollution

Air Pollution:

  • Primary Pollutants: Emitted directly from sources (e.g., CO₂, NOx).
  • Secondary Pollutants: Formed in the atmosphere (e.g., ozone).
  • Smog: A mixture of smoke and fog, often caused by industrial emissions.
  • Acid Rain: Caused by sulfur dioxide (SO₂) and nitrogen oxides (NOx), which combine with water vapor to form sulfuric and nitric acids.

Water Pollution:

  • Point Source Pollution: Pollution from a single, identifiable source (e.g., factory discharge).
  • Nonpoint Source Pollution: Pollution from diffuse sources (e.g., runoff from agricultural fields).
  • Eutrophication: Nutrient overload in water bodies, leading to algae blooms and oxygen depletion.

Solid Waste:

  • Municipal Solid Waste (MSW): Everyday items discarded by the public (e.g., paper, plastic).
  • Hazardous Waste: Waste that is harmful to humans and the environment (e.g., chemicals, batteries).
  • Recycling: The process of converting waste materials into new products to reduce waste and conserve resources.

8. Climate Change and Global Warming

Greenhouse Effect:

  • Natural Greenhouse Effect: Gases in the atmosphere trap heat, keeping the Earth warm enough to support life.
  • Enhanced Greenhouse Effect: Increased concentration of greenhouse gases (CO₂, CH₄, N₂O) due to human activities, leading to global warming.

Impacts of Climate Change:

  • Rising global temperatures, sea level rise, more extreme weather events, and disruption of ecosystems and agriculture.

Mitigation and Adaptation:

  • Mitigation: Reducing or preventing the emission of greenhouse gases (e.g., using renewable energy, reducing deforestation).
  • Adaptation: Adjusting human activities and infrastructure to cope with the impacts of climate change (e.g., building seawalls, changing agricultural practices).

9. Environmental Policy and Sustainability

Sustainability:

  • Meeting the needs of the present without compromising the ability of future generations to meet their own needs.

Environmental Laws and Policies:

  • Clean Air Act (CAA): Regulates air emissions from stationary and mobile sources.
  • Clean Water Act (CWA): Protects U.S. waters by regulating pollutant discharges.
  • Endangered Species Act (ESA): Protects species at risk of extinction.
  • Kyoto Protocol and Paris Agreement: International treaties aimed at reducing greenhouse gas emissions.