Ok, I figured it out and got all the exhibits built. Once I did that, it gave me the requirements to win the scenario, which are: 10 different animal species, Guest Happiness, Zoo Rating, Exhibit Rating and Animal Happiness all at 85 plus 850 guests. I've done this twice now, but both times it tells me I have lost. I know I have 10 different animal species because I get the message that say Congratulations you have 10 different animals. I also checked all exhibits to make sure the suitability was at least 85.