Getting the ranks of results from a query

I have a query of the form

select id from member order by age;

id
-----
431
93
202
467
300

In addition to the id, I would like the get the rank of the row--
in other words:

id | rank
-----+-----------
431 | 1
93 | 2
202 | 3
467 | 4
300 | 5

How do I do this with postgres? In the past, I have used something like

select id, identity(int, 1,1) from member order by age;

is there a postgres equivalent?

Thanks