Amides require much harsher conditions to hydrolyse than its ester homologue. An explanation given is that the orbitals holding the lone pair on the nitrogen overlaps with the C=O π-bond to give conjugation, thus introducing a "partial" π-bond between nitrogen and the carbonyl carbon. Consequently, this makes the bond harder to break.
However, for the ester homologue, doesn't this conjugation also happen? An explanation given is poorer overlapping of the orbitals. However, how is that true?
In addition, such explanation is given to show that C=O is shorter in ester than it is in amide. However, I still don't get why this is the case.