Third person singular/ plural for a collective?

[Joshuab]

Hi,

Merry Christmas!

Some examples: 'Homo Sapiens', 'Smith's' or 'Audience'. Are these singular, because they refer to a single group, or plural because there is more than one member?

I understand audience might be an exception, as an audience could be one person.

[Alan]

Homo Sapiens IS... (a species, singular)
The Smiths ARE... (= the Smith family members, plural)
AmE: The Audience IS.../ BrE: ...ARE or IS (a collective noun: BrE tends to allow either singular or plural)