Expert-level ecology covering population ecology, community ecology, ecosystem ecology, food webs, energy flow, nutrient cycling, biodiversity, and conservation biology.
Population growth: exponential (dN/dt = rN) and logistic (dN/dt = rN(K-N)/K). Carrying capacity K: maximum population size environment can support. Life tables: age-specific survival (lx) and fecundity (mx), net reproductive rate R0. Population regulation: density-dependent (competition, predation) vs density-independent. Metapopulation: network of subpopulations connected by dispersal, patch dynamics.
Species interactions: competition, predation, herbivory, mutualism, commensalism, parasitism. Competitive exclusion: two species with identical niches cannot coexist indefinitely. Niche theory: fundamental vs realized niche, niche partitioning enabling coexistence. Keystone species: disproportionate effect on community structure relative to abundance. Succession: primary and secondary, pioneer to climax communities.
Energy flow: trophic levels, 10% rule, primary productivity (GPP, NPP). Nutrient cycling: carbon, nitrogen, phosphorus cycles — reservoirs and fluxes. Trophic cascades: top-down effects of apex predators on lower trophic levels. Decomposition: detritivores, decomposers, mineralization of organic matter.
Alpha diversity: species richness and evenness within a habitat (Shannon, Simpson). Beta diversity: species turnover between habitats (Bray-Curtis, Jaccard). Gamma diversity: total diversity across a region. Species-area relationship: S = cA^z — islands and habitat fragments.
Extinction risk: IUCN Red List criteria, minimum viable population. Habitat fragmentation: edge effects, corridors, landscape connectivity. Invasive species: competitive displacement, novel weapons hypothesis. Climate change impacts: range shifts, phenological mismatches, coral bleaching.
| Pitfall | Fix |
|---|---|
| Ignoring scale dependence | Patterns differ at local vs regional vs global scales |
| Assuming equilibrium | Many ecological systems are non-equilibrium |
| Overlooking indirect interactions | Trait-mediated indirect effects can dominate |
| Confusing correlation with competition | Test with removal experiments |