This planet is our home. If we destroy the planet, we've destroyed our home, so it is fundamentally important. There are many different types of animals in the world.
Many animals are quite similar to each other.
Others are quite different. Animals can be classified based on their similarities. Continue on, and learn more about your fellow Earth inhabitants. The Animal Kingdom is at once the Kingdom most and least familiar to us. The same goes for several hundred thousand tiny insect-like species populating the Arthropoda phylum.