Related by context. Frequent words. (Click for all words.) 54 glaciation 53 interglacial 47 terrestrial ecosystems 46 Late Cretaceous 46 Little Ice Age 45 diatoms 44 Carboniferous 44 Cretaceous Period 43 Pleistocene 43 Quaternary 41 fossils 41 evolutionary adaptation 41 marine invertebrates 41 retreating glaciers 40 single celled organisms 40 glacial melting 40 Ross Ice Shelf 40 meltwater 40 marine reptiles 40 hominins 40 desiccation 40 lunar poles 39 multicellular organisms 39 mountain glaciers 39 freeze thaw cycles 38 lava flows 38 theropods 38 sauropods 38 Weddell Sea 38 Greenland Ice 37 picoseconds 37 mass extinction 37 multicellular 37 trilobites 37 glacial 37 glacial ice 37 Antarctic Peninsula 37 Archaeopteryx 37 hominids 37 glaciers 37 permafrost 36 flint tools 36 tyrannosaurs 36 carnivorous dinosaurs 36 moraines 36 fossil 36 archeological excavations 36 excavations 36 ICESat 36 Ardipithecus 36 glaciologists 35 icecap 35 Australopithecus 35 dinosaur fossils 35 archaeological excavations 35 morphological 35 megafauna 35 Tiktaalik 34 Paleolithic 34 radiocarbon dating 34 sauropod 34 degree Fahrenheit 34 Greenland glaciers 34 glacier 34 Neandertal 33 embryogenesis 33 glacier melt 33 prehistory 33 durations 33 hominin 33 polar 33 Australopithecus afarensis 33 prehistoric 33 snow melt 33 influenza pandemics 33 Arctic Ocean 33 snowline 33 icecaps 33 polar caps 33 gigatonnes 33 Neolithic 33 Homo sapiens 33 ice 32 vertebrate species 32 lava flow 32 #BC [003] 32 span 32 Homo erectus 32 Antarctic ice 32 Volcanic eruptions 32 polar ice 32 crystals 32 hominid 32 warming 32 arctic 32 thawing 32 tetrapods 31 spanning 31 melting 31 Iron Age 31 Greenland ice