Hierarchy is present in all social animals, including humans. I mean the ones that live in groups. Hierarchy is meant to decrease intraspecific aggression. To keep two males from fighting over every piece of food or a female, nature came up with ranks.

There's a very rigid hierarchy in the Civil Service.

Hierarchy is a social construct.

Japanese companies emphasize hierarchy.

The hierarchy of rank has long been fixed.

Hierarchy is against equality.

Peer helpers made the teacher's job a lot easier, but established a cruel hierarchy among the students.

Dominance hierarchy is a key part of animal behavior.

A tangled hierarchy is a hierarchical consciousness system in which a strange loop appears.

There's no such thing as a natural hierarchy.