When you first log in to your Zoo, you can see your Zoo Value, overall Zoo Happiness, Zoo Dollars, Wildlife Points, and number of visitors from the "Visit Zoo" flash. (Hint: click on "My Info" to see recent visitors and # of animals owned. It will also show the current number of tricks animals in your zoo have learned.) These are your Zoo stats and contribute to your Zoo's overall value.
You will also see the Achievement Banner on the top of the page. Each level you pass will earn you 1 Wildlife Point which can be used to get Ultra Rare animals and other cool things for your Zoo! You can also track your XP (experience points) in the bar below the Achievement Banner. XPs are earned by feeding your animals treats and collecting the full hearts they turn into when your animals are ready for more.