Related by context. Frequent words. (Click for all words.) 74 amphibian species 72 species 72 mammal species 65 bird species 64 primate species 63 frog species 62 vertebrates 61 avian species 61 amphibians 60 mammals 60 taxa 59 mammalian species 59 vertebrate 58 Critically Endangered 58 penguin species 58 biodiversity hotspots 58 coral species 58 western lowland gorillas 57 critically endangered species 57 orchid species 57 arthropod 56 critically endangered 55 invertebrates 55 ant species 55 mammal 55 subspecies 55 leatherback turtles 54 extinct species 54 multicellular 54 organisms 54 clades 54 megafauna 53 single celled organisms 53 phylogeny 53 Archaea 53 damselflies 53 coelacanth 53 tyrannosaur 53 carnivorous dinosaurs 53 terrestrial ecosystems 53 mammalian 52 marine turtles 52 eukaryotes 52 multicellular organisms 52 giant tortoises 52 extinctions 52 chytrid fungus 52 organism 52 genetically distinct 52 waterbirds 52 habitats 52 baleen whales 52 genera 52 Archaeopteryx 51 breeding pairs 51 freshwater ecosystems 51 nesting pairs 51 single celled 51 black footed ferret 51 Wolbachia 51 molluscs 51 IUCN Red 51 leatherback 51 arthropods 51 aquatic species 51 mountain gorillas 51 salamanders 51 sauropods 50 lineages 50 Amur tigers 50 biodiversity 50 marine biodiversity 50 Sumatran tigers 50 migratory species 50 Plasmodium 50 flowering plants 50 genus 50 archaea 50 taxonomic 50 Ardipithecus 50 marbled murrelet 50 theropods 49 ecosystems 49 zooplankton 49 Extinct 49 pygmy elephants 49 keystone species 49 eukaryotic 49 clouded leopard 49 Denisovans 49 primates 49 extinct 49 lemurs 49 subpopulations 49 rhinoviruses 49 baiji 49 biota 49 hominin 49 herbivores 49 Homo habilis 49 tetrapods