Related by context. Frequent words. (Click for all words.) 59 microfossils 58 protists 56 marine sediments 55 photosynthetic organisms 55 sedimentary layers 55 diatoms 55 marine invertebrates 55 flatworm 55 isotope ratios 55 pinhead sized 55 lake sediments 55 evolutionary origins 55 threadlike 54 concretions 54 systematics 54 diatom 54 elemental composition 54 radiocarbon dated 54 trilobites 54 slime molds 54 Chlamydomonas 54 snail shells 54 flatworms 54 Radiocarbon dating 54 fossilization 53 oxygen isotopes 53 fluorescently labeled 53 Scientists theorize 53 primitive organisms 53 otolith 53 coevolution 53 microscopic 53 faunal 53 trilobite 53 Diatoms 53 biogeography 53 photosynthetic bacteria 53 coprolites 53 Cyanobacteria 53 foraminifera 52 wormlike 52 single celled 52 scanning electron microscopy 52 mycelium 52 Fossilized 52 fossilized 52 vertebrate animals 52 dinoflagellate 52 Martian meteorites 52 isotopic composition 52 photosynthesizing 51 microbial ecology 51 DNA deoxyribonucleic acid 51 starch grains 51 amphipods 51 morphologically 51 morphologies 51 photochemistry 51 taxonomist 51 stromatolites 51 morphology 51 biogeochemical 51 teosinte 51 tunicates 50 Neoproterozoic 50 nanosized 50 inorganic compounds 50 multicellular 50 Ediacaran 50 angiosperms 50 mosasaurs 50 bacterium Escherichia coli 50 cone snails 50 genomic sequence 50 mitochondrial genome 50 underwater volcanoes 50 prokaryotes 50 radiocarbon dating 50 salt crystals 50 scanning electron microscope 50 aragonite 50 radiocarbon dates 50 Siberian permafrost 50 metagenomic 50 unicellular 50 ribosomal RNA 50 placental mammals 50 oxygen isotope 49 DNA helix 49 chloroplasts 49 Sinervo 49 macromolecule 49 prokaryotic 49 alga 49 nanobubbles 49 phylogeny 49 otoliths 49 phylogenetic analysis 49 submicroscopic 49 braincase 49 medullary bone