Say's Law

Biological Parallel

In ecosystems, production creates consumption opportunities. Photosynthesis creates ~50 billion tons of carbon annually in terrestrial plants, enabling 1.5 trillion tons of soil microbe biomass that couldn't exist without plant-fixed carbon. Whale falls on the ocean floor support 400+ scavenger species that emerge only when the supply (dead whale) creates the demand. Acacia trees exude extrafloral nectar (supply) that attracts ants (demand), which then defend the tree from herbivores—production of nectar created the conditions for ant protection services. Coral polyps produce calcium carbonate skeletons (supply) that enable 4,000+ reef species (demand) to colonize. Say's Law in biology: production enables niche construction, and niche construction creates cascading demand. Every producer creates opportunities for consumers, decomposers, and mutualists. Supply creates its own demand when outputs become inputs for other organisms.