Natural history History 417 Description and travel 383 Naturalists 110 Ecology 108 Science 104 Pre-Linnean works 99 plus ... Travel 97 Environmental conditions 93 Nature 82 Animals 80 Nature in literature 79 Social life and customs 68 Human ecology 65 Indians of North America 60 Knowledge 57 Discovery and exploration 53 History and criticism 51 Mollusks 46 Geology 44 Philosophy 42 Effect of human beings on 41 Zoology 41 Evolution (Biology) 37 Homes and haunts 37 Scientific expeditions 34 Biotic communities 32 Physical geography 32 Study and teaching 31 Wilderness areas 31 moins ...