At its beginning and endpoints, the civil service was (is) based on in the years between it was based on

I believe tha answer is: merit/patronage

In merit based civil service, the public servant is being chosen based on their Skills/capabilities in the related field.
Patronage based civil service, on the other hand, would chooese the public servants based on inside connection that they have with existing government officials.

Ifound this on google “the change in control meant as house minority leader, pelosi was widely expected to become speaker of the house in the next congress. on november 16, 2006, the democratic caucus unanimously chose pelosi as the democratic candidate for speaker.” i hope this