Really short...but kinda interesting =/
If you imagine condensing an entire zoo and aquarium in one large dome, that's the Biodome in a nutshell. While it is interesting seeing different species of animals in 3 different habitats, the selection of the creatures was relatively limited and the novelty quickly wore off as you explore the entire "zoo" in less than one hour. I'm a little bit more bitter as my umbrella fell from my bag while going through the zoo, and within 5 minutes of noticing that it was missing, I had back-tracked and realized that someone else had taken it.
I think if you do decide to visit this area, I'd recommend purchasing the combined ticket, but more to see the insectarium, and checking this place out after you've thoroughly explored the beautiful botanical garden.
Definitely bring your student ID, it saved us a lot of money!