The word population is used in statistics for the set of
data being looked at. It may concern people, but could equally
well be concerned with the size of pebbles on a beach.
shares a particular characteristic of interest most often
that of living in a given geographic area. In taxonomy population
is a low-level taxonomic rank.
For example, a coffee shop
that wants to sell to a younger audience looks at the demographics
of an area to be able to appeal to this younger audience.