Grade 5 Social Science: Topic - World Geography; Island & Rain Forests / There are two types of ecosystems discussed in this book: the island and the rainforest. A chapter is dedicated to each. In chapter one expect to read about the characteristics of an island ecosystem including examples how they were formed and the types of islands. In chapter two you will be reading about the definition of a rainforest ecosystem and the types of rain forests and where you can find them.