DNA life_page life life_defined LUCA life_arguments first_life_form evolution_unplanned sexual_reproduction evolution Carl_Linnaeus evolutionary_milestones taxonomy Eukaryote taxonomic_morphology eukaryote multicellular_creatures plants_300K plant_species fungiculture animals_1.5M animal_species carbon_dioxide fungi_3M fungus_species yeast yeasts microorganism microorganisms biofilm microorganism_taxa microorganism_presence electron_microscope microorganism_visiblity organisms human_behaviour religions roundworm gradation ecosystem community_of_organisms scale_of_ecosystems antarctic_ecosystem systema_naturae William_Smith how_life_evolved William_Smith_survey William_Smiths_maps_books Smiths_observations