Related by context. Frequent words. (Click for all words.) 46 species 45 keystone species 44 megafauna 44 apex predators 44 amphibian populations 43 habitat fragmentation 42 overhunting 42 mammals 42 vertebrate species 41 genetically distinct 41 species extinctions 41 frog species 41 Poinar 41 extinction 41 pikas 40 endangered 40 feathered dinosaurs 40 thylacine 40 mammal species 40 extinct 40 mammal 40 black footed ferret 40 mean 39 amphibians 39 Whooping cranes 39 amphibian species 39 periodical cicadas 39 Florida panthers 39 Florida panther 39 genetic diversity 38 woolly mammoths 38 deluding ourselves 38 extinctions 38 tyrannosaur 38 extinct species 38 mountain caribou 38 monkeys apes 37 avian species 37 infects humans 37 freshwater turtles 37 pika 37 dinosaurs roamed 37 baiji 37 brink 37 homo sapiens 37 Anthropocene 37 verge 37 chytrid fungus 37 mass extinction 36 tyrannosaurs 36 Invasive species 36 critically endangered species 36 primate species 36 vertebrates 36 ocean ecosystems 36 threaten 36 yellow legged frog 36 mammoths 36 Yellowstone ecosystem 36 Tasmanian tiger 36 dinosaurs 36 mass extinctions 36 theropod 36 story div.onclick = 36 plugin document.write 36 plesiosaur 36 mastodons 35 bird species 35 Steller sea lions 35 predation 35 bee populations 35 habitat degradation 35 threatened 35 speciation 35 genus Homo 35 saola 35 endangered species 35 Cook Inlet belugas 35 danger 35 flightless birds 35 caribou herd 35 honeybee population 35 flycatcher 34 Amstrup 34 woolly mammoth 34 terrestrial ecosystems 34 Homo sapiens 34 wooly mammoth 34 Extinct 34 herbivorous 34 sagebrush habitat 34 ecosystems 34 imminent danger 34 seagrasses 34 temperate forests 34 California condors 34 breeding colonies 34 petrels 34 saber toothed cats 34 carnivorous dinosaurs 34 Cambrian explosion