Sustainability
Sustainability is living within Earth’s limits, it matters because natural systems support life, and humans disrupt it by overusing resources faster than they regenerate.
3 Scientific Principles of Sustainability
Sustainability depends on solar energy, biodiversity, and chemical cycling, and humans undermine all three through fossil fuels, habitat loss, and pollution.
Natural Capital
Natural capital includes Earth’s resources and ecosystem services, it matters because economies and life depend on it, and humans degrade it through overextraction and pollution.
Ecosystem Services
Ecosystem services are free benefits from nature that support life, and when humans damage ecosystems these services decline or disappear.
Ecological Footprint
An ecological footprint measures how much land and water a population needs, it matters because it shows sustainability, and humans create deficits by overshooting biocapacity.
IPAT
IPAT shows environmental impact equals population times affluence times technology, and humans increase impact by growing populations and consumption.
Tragedy of the Commons
The tragedy of the commons occurs when shared resources are overused, it matters because it leads to depletion, and humans cause it without regulation or cooperation.
Scientific Method
The scientific method tests hypotheses to understand natural systems, and ignoring science leads humans to make harmful environmental decisions.
Laws of Thermodynamics
Energy is conserved but degrades in quality, meaning humans cannot recycle energy and waste heat increases environmental stress.
High vs Low Quality Energy
High-quality energy does more work while low-quality energy is dispersed heat, and humans accelerate energy loss through inefficient systems.
Systems & Feedback
Systems respond through feedback loops, and human activity triggers positive feedbacks that worsen environmental problems.
Ecosystems
community of living organisms (plants, animals, microbes) interacting with each other and their non-living (abiotic) environment
Producers & Consumers
Producers capture solar energy while consumers depend on them, and human actions that reduce producers collapse food webs.
Food Chains & Webs
Food chains show linear energy flow while food webs show complexity, and humans disrupt them by removing species.
10% Rule
Only 10% of energy transfers between trophic levels, meaning humans waste energy by eating high on the food chain.
GPP vs NPP
GPP is total energy captured while NPP is energy available to consumers, and human damage lowers ecosystem productivity.
Nutrient Cycles
like carbon, nitrogen, phosphorus, water) move between living organisms (biotic) and the non-living environment (abiotic, e.g., soil, air, water) in a continuous loop, ensuring these vital materials are recycled and made available to sustain life
Biodiversity
The vast variety of life on Earth, encompassing all living things from genes to species to ecosystems
Natural Selection
Evolution where organisms better adapted to their environment are more likely to survive, reproduce, and pass on their advantageous, heritable traits to offspring
Specialist vs Generalist
Specialists have narrow niches while generalists are adaptable, and specialists are more vulnerable to human disturbance.
Island Biogeography
Species richness depends on island size and distance, and human fragmentation creates “islands” that lose species.
Keystone Species
Keystone species have outsized ecosystem impact, and removing them causes ecosystem collapse.
Species Interactions
Species interact through competition, predation, and symbiosis, and human interference destabilizes these relationships.
Succession
Succession is ecosystem recovery after disturbance, and human disturbances slow or prevent recovery.
