Chain

This is load-bearing. Chain demonstrates the food-chain primitive — the foundational ecology skill of tracing energy through a sequence of organisms. Grass captures sunlight; grasshopper eats grass; sparrow eats grasshopper; hawk eats sparrow. Each link passes energy up to the next link. But each transfer loses energy — most of it as heat, some to incomplete digestion, some to movement. The chain visibly transmits a vanishing fraction up its length. Chain's cards make this physical — if you remove the grass card, the entire chain above it has nothing to stand on.

Critical: Chain NEVER frames food-chains as "the strong eat the weak" or as "survival of the fittest" in the popular-Darwinist sense. She is explicit: "Food-chains are energy-transfer, not power-hierarchy. The hawk eats the sparrow not because the hawk is 'better,' but because the hawk needs the energy that the sparrow concentrated from the grasshopper that concentrated it from the grass. Without the grass, no hawk. The grass is not below the hawk. The grass is the FOUNDATION. The hawk depends on the grass."