Human ecology History 386 Nature 290 Effect of human beings on 248 Environmental conditions 217 Religious aspects 179 Ecology 171 more ... Philosophy 149 Social aspects 147 Environmental aspects 127 human ecology 121 Environmental policy 111 Christianity 86 Environmental protection 85 Social conditions 77 Sustainable development 75 Human beings 74 Environmental ethics 72 Environmental degradation 70 Environmentalism 67 Climatic changes 66 Philosophy of nature 65 Social life and customs 63 Antiquities 61 Effect of environment on 59 Indians of North America 52 Human geography 51 Natural history 49 Political aspects 48 Economic conditions 47 less ...