Practice question

Habitat loss, overharvesting, and introduced species are major direct drivers of biodiversity decline. They reduce population sizes, fragment habitats, remove organisms faster than replacement, or alter competition, predation, and disease. Solar radiation is a fundamental environmental energy source and varies naturally with latitude and season; it is not normally listed as a contemporary anthropogenic driver comparable to land-use change, exploitation, invasive species, pollution, and climate change. Mechanistic interpretation connects individual physiology and species interactions to population change, community composition, and ecosystem-level fluxes. Reliable inference requires the complete experimental design, definitions, units, and statistical evidence; missing labels cannot be reconstructed from an answer key alone. Net primary production equals gross primary production minus plant respiration and represents biomass or energy made available for growth and consumers. Rates must be compared on the same area, biomass, leaf-area, and time basis because changing the denominator can reverse an apparent ecosystem ranking. Climate, nutrients, disturbance, species traits, and food-web structure interact, so broad ecological generalisations describe tendencies rather than universal rules.