Even before humans entered the scene, many species of plants and animals were extinct and have been going extinct ever since the first organisms evolved on Earth. New ones constantly are evolving to fill niches and adapt to changing environments. Why are we even concerned about endangered species? If one species goes extinct won’t another replace it? Do we need all of these species anyway? Should humans have the right to inhabit anyplace we want to without worrying about which little animal/plan/fungus we trample?