Related by context. Frequent words. (Click for all words.) 62 Jurassic Period 59 Cretaceous Period 54 Late Triassic 53 supercontinent 51 Pleistocene era 51 archaea 50 hydrothermal vent 50 Late Cretaceous 50 trilobites 50 Cambrian explosion 50 single celled organisms 50 subtropical regions 49 interglacial period 49 angiosperms 49 Carboniferous 49 temperate zones 49 stromatolites 48 Beringia 48 marine reptiles 48 Palaeolithic 48 plesiosaurs 48 slime molds 48 Cyanobacteria 47 single celled 47 Snowball Earth 47 dinosaurs roamed 47 Early Cretaceous 47 Pliocene 47 microfossils 47 Equatorial Pacific 47 multicellular organisms 47 Posted -# sec 47 Little Ice Age 47 vertebrate animals 47 fungi 46 Poinar 46 multicellular 46 glaciations 46 temperate forests 46 feathered dinosaurs 46 lava tubes 46 Medieval Warm Period 46 Pleistocene 46 Younger Dryas 46 underwater volcanoes 46 tropics 46 Dry Valleys 46 glaciation 45 Cro Magnons 45 H. sapiens 45 placental mammals 45 unicellular 45 classical antiquity 45 Gregor Mendel 45 Ordovician 45 Volcanic eruptions 45 Sumerians 45 severe droughts 45 humid tropical 45 millenniums 45 Etruscans 45 dinosaurs 45 mass extinctions 45 Homo sapiens 45 humans 45 Burgess Shale 45 terrestrial ecosystems 45 Ardipithecus ramidus 45 Fertile Crescent 45 Mesozoic 45 Mesolithic 45 theropod dinosaurs 45 Cretaceous 45 Neandertals 44 solar nebula 44 megafauna 44 biogeography 44 temperate regions 44 Olmecs 44 mycology 44 diatoms 44 radiocarbon dated 44 Archaea 44 faunal 44 voyaged 44 H. erectus 44 Weddell Sea 44 landmasses 44 Homo habilis 44 carnivorous plants 44 Malay Archipelago 44 degrees Fahrenheit warmer 44 Cenozoic 44 prehistoric 44 interglacial 44 Tang Dynasty #-# 44 Archaean 44 systematics 44 Ardipithecus 44 clathrates 44 foraminifera