From Grizzly Ridge to the Tiger Valley, Akron Public Schools students and their families took a safari at the Akron Zoo filling donated backpacks with back-to-school goodies.The two-day program, Backpack Adventure at the Zoo, started Tuesday and concludes Wednesday. Some 2,500 elementary students registered ahead of time to participate.The event program was started eight years ago by former trustees of the Akron Zoo, which has an overlapping interest with schools.“Obviously Akron Public Schools is all about the kids, so it was just a good fit for the zoo,” said David Barnhardt, director of Marketing and Guest Services for the Akron Zoo.