the.com/food chain

means The sequence of who-eats-whom in an ecosystem, running from sunlight-capturing plants up through the animals that eat them and the animals that eat those.

from A straightforward 20th-century ecology term, built from 'food' plus 'chain' as a metaphor for linked rings — each organism a link, feeding the next. It entered scientific use alongside ideas like the 'food web' as ecologists in the early-to-mid 1900s mapped how energy moves through nature; it later escaped into general use as a handy way to talk about hierarchies, pecking orders, and who's really running the office.