Ecosystem: A biological community of interacting organisms (plants, animals) and their physical environment (soil, water, air).
Components:
Biotic Factors: Living components (plants, animals).
Abiotic Factors: Non-living components (water, temperature, soil, sunlight).
Energy Flow: Sunlight → Producers (plants) → Consumers (herbivores, carnivores) → Decomposers (fungi, bacteria). Energy is lost at each level (about 90%).
Food Web vs. Food Chain: A food chain shows one path of energy, while a food web shows multiple paths.
Biomes: Large, geographically distinct areas with specific climates and ecosystems.
Tropical Rainforest: Warm, wet year-round, high biodiversity.
Desert: Dry, extreme temperature variation, few organisms.
Tundra: Cold, little precipitation, low biodiversity, permafrost.
Temperate Forest: Four seasons, deciduous trees.
Savanna: Grasslands with scattered trees, seasonal rainfall.
Grasslands: Flat areas with few trees, moderate rainfall.
Species Diversity: The variety of different species in an area (important for ecosystem health).
Genetic Diversity: The variety of genes within a species, which allows for adaptation and resilience.
Ecosystem Diversity: The variety of ecosystems in a region, from forests to wetlands to deserts.
Keystone Species: Species whose role in the ecosystem is disproportionately large compared to their abundance (e.g., sea otters control sea urchin populations, which protects kelp forests).
Biodiversity Loss:
Habitat Loss: Destruction or alteration of habitats (e.g., deforestation).
Overexploitation: Overhunting, overfishing, or overharvesting.
Invasive Species: Non-native species that outcompete local species.
Climate Change: Altered habitats or temperature changes affect species survival.
Water Cycle:
Evaporation: Water from oceans, rivers, and lakes turns into vapor.
Transpiration: Water released by plants into the atmosphere.
Condensation: Water vapor cools and forms clouds.
Precipitation: Rain, snow, etc., falls back to Earth.
Runoff: Water moves across the land back to bodies of water.
Carbon Cycle:
Photosynthesis: Plants absorb CO₂ to make glucose.
Respiration: Animals and plants release CO₂ back into the atmosphere.
Decomposition: Dead organisms are broken down, releasing carbon into the soil.
Fossil Fuels: Burning fossil fuels releases large amounts of CO₂, contributing to climate change.
Nitrogen Cycle:
Nitrogen Fixation: Certain bacteria convert nitrogen gas (N₂) into ammonia (NH₃) or nitrate (NO₃⁻) usable by plants.
Nitrification: Bacteria convert ammonia into nitrites and nitrates.
Assimilation: Plants take up nitrogen compounds and animals eat the plants.
Denitrification: Bacteria convert nitrates back into nitrogen gas, releasing it into the atmosphere.
Phosphorus Cycle:
Weathering: Rocks release phosphate (PO₄³⁻) into soil and water.
Absorption: Plants take up phosphate; animals eat plants.
Decomposition: Decomposers release phosphorus back into the soil.
No Atmospheric Component: Unlike carbon and nitrogen, phosphorus does not exist in the atmosphere, making the cycle slower.
Air Pollution:
Sources: Fossil fuel burning (cars, factories).
Pollutants: Carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen oxides (NOx), particulate matter.
Acid Rain: Sulfur dioxide and nitrogen oxides combine with water vapor to form sulfuric and nitric acid, damaging ecosystems.
Ozone Depletion: Chlorofluorocarbons (CFCs) damage the ozone layer, which protects us from UV radiation.
Water Pollution:
Nutrient Pollution: Excess nitrogen and phosphorus from agriculture cause algal blooms, depleting oxygen and harming aquatic life.
Plastic Pollution: Non-biodegradable plastic accumulates in oceans and harms marine species.
Thermal Pollution: Heat from industrial processes raises water temperatures, reducing oxygen levels and harming aquatic life.
Land Pollution:
Deforestation: Large-scale removal of trees disrupts ecosystems and increases CO₂ levels.
Waste Disposal: Landfills and illegal dumping of chemicals cause soil contamination.
Climate Change:
Global Warming: Greenhouse gases (CO₂, methane) trap heat in the atmosphere, leading to rising global temperatures.
Impacts: Melting ice caps, rising sea levels, extreme weather events, and habitat disruption.
Deforestation: Clearing forests for agriculture or development reduces biodiversity and contributes to carbon emissions.
Habitat Fragmentation: Breaking large habitats into smaller, isolated patches reduces biodiversity and makes it harder for species to survive.
Overfishing: Depletes fish populations and harms aquatic ecosystems.
Pollution: Industrial and agricultural practices contaminate air, water, and soil, harming ecosystems and human health.
Invasive Species: Non-native species introduced by humans can disrupt local ecosystems by outcompeting or preying on native species.
Sustainable Development: Balancing human needs with the health of the planet, ensuring resources are available for future generations.
Renewable Resources: Resources that can be replenished naturally (solar, wind, geothermal, biomass).
Nonrenewable Resources: Resources that cannot be replaced on a human timescale (coal, oil, natural gas).
Conservation: Protecting ecosystems, conserving resources, and reducing waste (e.g., using less water, recycling).
EPA (Environmental Protection Agency): Government agency that works to protect the environment and public health.
Clean Water Act: Federal law that regulates the discharge of pollutants into U.S. waters to ensure water quality.
Endangered Species Act: Protects species that are at risk of extinction by preventing their exploitation and conserving their habitats.
Kyoto Protocol/Paris Agreement: International agreements aimed at reducing global greenhouse gas emissions to combat climate change.