What does food chain mean?

food chain

n.

1. A succession of organisms in an ecological community that constitutes a continuation of food energy from one organism to another as each consumes a lower member and in turn is preyed upon by a higher member.

2. Informal. A competitive hierarchy: "was reduced to character roles while struggling to defend his position in the Hollywood food chain" (Kathryn Shattuck).

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OR

the flow of energy from one organism to another.