Related by context. Frequent words. (Click for all words.) 60 placental mammals 60 taxa 59 angiosperms 58 temperate zones 58 terrestrial ecosystems 58 nitrogen fixation 57 morphologically 57 isoprene 57 subfamily 57 temperate forests 56 multicellular organisms 56 symbionts 55 temperate regions 55 nitrogen fixing 55 forbs 54 photosynthetic 54 poleward 54 multicellular 54 Younger Dryas 54 atmospheric nitrogen 54 Archaea 54 vertebrate animals 54 atmospheric CO 53 biogeography 53 Ardipithecus ramidus 53 diatoms 53 atmospheric methane 53 hydrological cycle 53 prokaryotes 52 isotope ratios 52 eukaryotic 52 morphologies 52 oxygen isotopes 52 systematics 52 herbaceous plants 52 biome 52 Medieval Warm Period 52 acidic soils 52 tetrapod 52 convergent evolution 52 archaea 52 interglacial period 52 planktonic 52 Fig. 1A 52 faunal 52 phylogeny 52 clades 51 subtropics 51 H. erectus 51 phyla 51 morphological 51 vertebrates 51 vertebrate 51 crocodilians 51 Little Ice Age 51 foraminifera 51 atmospheric CO2 51 Arabidopsis 51 mid latitudes 51 deciduous forest 50 Cyanobacteria 50 isotopic composition 50 desiccation 50 atmospheric circulation 50 Phytophthora 50 evolutionary adaptation 50 glaciation 50 Late Cretaceous 50 biogeochemical 50 Indohyus 50 single celled organisms 50 solar irradiance 50 Pacific Decadal Oscillation 50 lineages 50 maxima 50 climatically 50 phenology 50 microbiota 49 eukaryotic cells 49 chloroplast 49 SSTs 49 interglacial 49 Tiktaalik 49 biogenic 49 El Niños 49 atmospheric carbon dioxide 49 photosynthesis 49 mycelium 49 inflorescence 49 methanogens 49 lake sediments 49 species 49 hominins 49 lowland forests 49 theropods 49 megafauna 49 genus Homo 49 Caenorhabditis elegans 49 Cambrian explosion 49 igneous rocks 49 Homo sapiens