I've worked with these folks at UW and tested their "Halobacteria" Labs in my classroom. If you're in a low-income school, they'll send you everything for free. Halobacteria are a great, resiliant model organism to grow in your classroom. Also Sea Monkeys (Brine Shrimp) love them and you can do a whole salty ecological community. They have lots of modules on Systems Thinking and dyanamic biological and environmental systems. Love their "cell phone" unit.