Plain-language explanation.
Ecology is the study of how living things interact with each other and with their environment. Food webs show how energy flows through ecosystems from plants to herbivores to predators. Nutrients like nitrogen and carbon cycle through ecosystems. Humans are disrupting these natural cycles in many ways.
Core concepts and standard treatment.
Ecology operates at population (dynamics, life history strategies, competition, predation), community (species interactions, diversity, succession), ecosystem (energy flow, nutrient cycling, productivity), and landscape (spatial heterogeneity, habitat connectivity, metapopulation dynamics) levels. The carbon cycle, nitrogen cycle, phosphorus cycle, and water cycle link biological and geochemical processes.
Deeper theory, debates and edge cases.
Trophic cascade theory demonstrates how apex predator removal triggers cascading effects — illustrated by wolf reintroduction in Yellowstone. Regime shifts (alternative stable states theory) explain abrupt transitions in ecosystems — lake eutrophication, coral reef bleaching, savanna-forest transitions — with hysteresis making recovery harder than the original degradation. Metabolic theory of ecology uses body size and temperature to predict metabolic rates.
How it is applied in practice.
Applied ecology informs conservation planning: systematic conservation planning uses spatial prioritisation algorithms (Marxan) to identify reserve networks. Ecological restoration practitioners use reference ecosystems and functional trait approaches to guide restoration targets. Environmental flows (e-flows) quantify the minimum water regime required to maintain freshwater ecosystem function. Biosecurity and invasion biology develop detection, containment, and eradication strategies for invasive species with economic tools quantifying invasion costs and intervention benefits.