There are a lot of human activities that gives negative effects on the earth's ecosystem but I will mention only four: Burning of things such as garbages or plants and trees, dumping of garbages anywhere, chemical substance that are being made and produced, cutting down of trees for replacement of buildings and homes. The human activities increase the occurrence of species extinction by doing this, it eliminates and destroy the homes of the species that are supposed to be living on their natural habitat. But instead of them, living peacefully, by doing these activities, their home will be destroyed that can kill them-- which can lead to extinction.