Well, most of the species on the planet are vital to out survival. If one big animal in the food chain disappears, we may suffer terribly from the loss. Some animals are already in danger of becoming extinct because of human activities. I am not implying that we could destroy the world, but we will destroy ourselves. Nature will soon adapt without humans. We aren't the main thing on earth. In a nutshell, we have to protect animals to protect ourselves. Sounds too selfish? We protect them to stabilize our food chain
:) Hope I helped! :)
