Related by context. Frequent words. (Click for all words.) 61 mammals 59 vertebrate species 58 Archaeopteryx 58 megafauna 58 Homo sapiens 57 taxa 57 vertebrate 57 multicellular 56 multicellular organisms 56 carnivorous dinosaurs 56 dinosaurs 56 species 56 vertebrates 56 Cretaceous Period 55 arthropods 55 Late Cretaceous 54 tetrapods 54 Neandertals 54 theropods 54 hominins 53 arthropod 53 herbivores 53 Tiktaalik 53 homo sapiens 53 herbivorous 53 clades 53 fossil 53 hominids 53 terrestrial ecosystems 53 Ardipithecus 52 single celled 52 lineages 52 Mesozoic 52 mass extinction 52 single celled organisms 52 phylum 52 mammalian 51 humans 51 primate species 51 baleen whales 51 Australopithecus 51 eukaryotes 51 mammal 51 mammoths 51 tyrannosaur 51 hominid 51 fossils 51 mammal species 51 avian species 51 Archaea 50 phylogeny 50 extinct 50 Homo erectus 50 genus 50 temperate zones 50 carnivores 50 biota 50 overhunting 50 archaea 50 genera 50 organisms 50 herbivore 50 clade 49 tyrannosaurs 49 sauropods 49 pterosaurs 49 mass extinctions 49 domesticated 49 interbred 49 Homo habilis 49 diatoms 49 ant species 49 amphibian species 49 Cretaceous 49 mammalian species 49 speciation 49 morphologies 48 common ancestor 48 genetically distinct 48 arboreal 48 extinctions 48 petrels 48 phylogenetic 48 flightless birds 48 creatures 48 sauropod 47 interglacial 47 lifeforms 47 Australopithecus afarensis 47 primates 47 Neanderthals 47 bipedal 47 Homo floresiensis 47 evolutionary 47 dinosaurs roamed 47 zooplankton 47 anatomically modern 47 interbreeding 47 prehistoric 47 fossilized remains 47 prehistoric creatures