Welcome to the forum, zooworker.
I hope I don't offend you, however, when I point out that there are three legitimate functions of a zoo, not just two.
These are Conservation, Education and RECREATION ( that is, the provision of a recreation facility, somewhere that ordinary people can go to actually see animals "in the flesh", not just in books and on T.V.) As far as I am concerned that is just as important a function as conservation and education. I'm aware that many people wouldn't agree with that, but I would regard them as being idealistic rather than realistic.
I strongly agree Ara that RECREATION is an important reason for a zoo's existence - and people subliminally can be educated while enjoying their recreation.
I'd also like to offer another word - PRESERVATION. As we at DDZ struggle with the mountain of paperwork involved in our ARAZPA application we are continually having doubts as to the true worth of our zoo to conservation. We have no wish to return endangered species of animals to the wild, given that the conditions that caused them to become endangered in the first place still exist. We don't see that our little zoo will ever be able to raise enough funds for any worthwhile in-situ programs. We are never going to be a huge urban zoo with tens of thousands of people participating in our education programs. What CAN we do?
PRESERVATION seems to us to be the reason for our existence. We can be a repository for species that have no hope of ever being returned to the wild - house and display bachelor groups etc, individuals surplus to breeding programs for whatever reason, take part in breeding programs that are within our means - all that sort of thing.