AP env sci ch 1-5

Unit 1: Ecosystems (Modules 0–7) Study Guide

Environmental Science & Indicators

  • Study of Environmental Science: The study of how humans interact with the environment, combining biology, chemistry, physics, economics, and social sciences.

  • Environmental Indicators: Measurements that tell us about the health of ecosystems (e.g., biodiversity, food production, CO₂ levels, average global temperature, human population, resource depletion).

Anthropogenic

  • Anthropogenic: Human-caused. Refers to environmental changes caused by human activity (e.g., pollution, deforestation, greenhouse gases).

Ecological Footprint

  • Definition: The measure of how much land and resources are needed to support a person/population’s lifestyle.

  • Factors affecting size: Diet, energy use, transportation, waste production, consumption habits.

Experiments

  • Natural Experiment: Observes events that occur in nature (e.g., volcanic eruption impacts).

  • Controlled Experiment: Performed under controlled conditions, manipulating one variable at a time.

Laws of Thermodynamics & Conservation

  1. First Law (Conservation of Energy): Energy cannot be created or destroyed, only transformed.

  2. Second Law: Energy transformations increase entropy (disorder); energy is lost as heat.

  3. Law of Conservation of Matter: Matter cannot be created or destroyed, only transformed.

Coal Energy Problem

  • Given: 24,000 MJ. Efficiencies = 0.8 × 0.3 × 0.9 × 0.6 = 12.96% total efficiency.

  • Energy as light: 24,000 MJ × 0.1296 ≈ 3,110 MJ produces light.

  • Rest: Lost as heat, sound, friction, waste.

Extinction Rates

  • Background extinction rate: ~1 species per million per year.

  • Current rate: ~100–1,000 times higher due to human impact.

Water Cycle

  • Stages: Evaporation, condensation, precipitation, infiltration, runoff, transpiration.

  • Watershed: Area of land where all water drains into a single river, lake, or ocean.

Biogeochemical Cycles

  • Nitrogen Cycle: Fixation → Nitrification → Assimilation → Ammonification → Denitrification.

  • Carbon Cycle: Photosynthesis, respiration, fossil fuels, ocean uptake.

  • Oxygen Cycle: Linked to carbon cycle via photosynthesis & respiration.

  • Sulfur Cycle: Volcanoes (natural), burning coal (human), enters air as SO₂.

  • Phosphorus Cycle: Weathering of rocks, no gaseous stage, returns slowly.

  • Global Warming Effect: Increases CO₂ in atmosphere, alters carbon balance.

  • Anthropogenic vs. Natural Sources:

    • Sulfur: Burning coal (human), volcanoes (natural).

    • Phosphorus: Fertilizers (human), rock weathering (natural).

  • Phosphorus cycle is slow: Lacks gaseous stage; depends on rock weathering.

Biomes

  • Two main factors: Temperature & precipitation.

  • Traveling Oregon → New York: Coastal rainforest → mountains → prairies → deciduous forest.

  • Similar latitudes differ: Rain shadows, ocean currents, mountain ranges.

  • Examples:

    • Desert → cacti, reptiles.

    • Grassland → bison, grasses.

    • Tropical rainforest → jaguars, high plant diversity.

  • Aquatic biomes with most life: Coral reefs & estuaries.

  • Lake development: Oligotrophic (low nutrients) → Mesotrophic → Eutrophic (high nutrients).

  • Wetlands/Marshes/Swamps: Filter water, prevent flooding, provide habitat.

  • Coral reef problems: Bleaching, ocean acidification, pollution.

  • Photic zone: Sunlit, supports photosynthesis.

  • Aphotic zone: Dark, organisms adapt (bioluminescence, slow metabolism).

Ecosystems

  • Definition: Community of organisms + their environment.

  • Disturbance: A change that alters ecosystem structure (fire, storm).

    • Beneficial: Maintains diversity (small fires).

    • Detrimental: Too severe, causes collapse.

Biodiversity & Population

  • Types: Genetic, species, ecosystem diversity.

  • Biotic vs. Abiotic: Living vs. nonliving components.

  • Limiting factors: Resources (food, water), space, competition, climate.

  • Food web categories: Producers, consumers (herbivore, carnivore, omnivore), decomposers.

  • Energy in biomes: Tropical rainforests & estuaries have most energy (high productivity).

  • Decomposers’ role: Recycle nutrients.

  • Deciduous forest examples: Producer = oak tree, Consumer = deer, Decomposer = fungi.

  • NPP (Net Primary Productivity): Energy available to consumers. Highest in tropics, lowest at poles.

  • Energy transfer: ~10% between trophic levels. Explains why few tertiary consumers exist.

Energy in Ecosystems

  • Types of energy: Kinetic, potential, chemical.

  • Flow: One-way; sun → producers → consumers → decomposers.

  • Biomass: Decreases at higher trophic levels.

  • Ecological efficiency: Energy transfer efficiency (~10%).

  • Sun’s energy: Visible light, UV, infrared.

  • Energy transfer methods: Conduction, convection, radiation.

  • “No away”: Matter cycles; waste stays on Earth.

  • Waste product of energy use: Heat.

  • Energy efficiency helps: Reduces resource use, pollution.

Species Interactions

  • Competition: Occurs when species use same resource. Called interspecific competition.

  • Predator techniques: Speed, camouflage, packs, ambush.

  • Defenses: Camouflage, mimicry, spines, toxins.

  • Parasites: Weaken but rarely kill hosts; often specialized.

  • Mutualism: Both benefit (bees & flowers).

  • Commensalism: One benefits, other unaffected (barnacles on whales).

  • Parasitism: Parasite benefits, host harmed (ticks on deer).

  • Pathogens: Disease-causing (viruses, bacteria).

Invasive Species & Biodiversity Protection

  • Exotic species: Non-native to ecosystem.

  • Invasive species: Exotic species that harm ecosystems.

  • Why they dominate: Lack predators, reproduce quickly.

  • Examples USA:

    • Aquatic: Zebra mussels, Asian carp.

    • Terrestrial: Kudzu vine, European starling.

  • Overharvesting: Excessive hunting/fishing (cod, elephants for ivory).

  • Protection laws: Endangered Species Act, CITES, Marine Mammal Protection Act.