Extinction (Biology) Effect of human beings on 37 Nature 31 Catastrophes (Geology) 24 Paleontology 21 Biodiversity 20 Biodiversity conservation 20 plus ... Endangered species 14 Mass extinctions 14 Wildlife conservation 14 Climatic changes 12 Evolution (Biology) 12 History 9 Extinct animals 8 Paleoecology 8 Social aspects 8 Glacial epoch 7 Paleoclimatology 7 Environmental aspects 5 Environmental degradation 5 Historical geology 5 Mammals 5 Moral and ethical aspects 5 Nature conservation 5 Philosophy 5 Conservation 4 Conservation of natural resources 4 Cretaceous-Paleogene boundary 4 Ecology 4 Environmental policy 4 moins ...