Is there a word which describes "one of many"?

Are there any words that have this meaning? One of many, as in a person out of many people.

Clarification: The single individual or item is similar to the group and not unique in any way.

Solution 1:

Specimen - An individual animal, plant, piece of a mineral, etc. used as an example of its species or type for scientific study or display.

'Carla could not help feeling a degree of reluctant admiration for this odd female specimen'

ODO.

Solution 2:

Depending on context, the word clone might suit. One of the definitions given in the Oxford Dictionary online is:

clone

1.1 A person or thing regarded as an exact copy of another.

‘guitarists who are labelled Hendrix clones’

(Whatever a Hendrix may be.)

However it is a neologism, and I would not advise its use in formal writing.

Another possibility (again reflecting my scientific background) is instance.

instance

1 An example or single occurrence of something.

‘the search finds every instance where the word appears’