The Chain of Being and a New Taxonomy in the 1700S, Charles

Home , Archaeoglobus, Carl Linnaeus, Eukaryote, Systema Naturae

these livingthings. develop ataxonomic model that organizes group theseorganisms? Usethecards to have observed at thetime.How would you represent thetypesoforganisms you could who adopts thisnew taxonomy. The cards Imagine that you are abiologist in1735 shared characteristics. and namingofgroups oforganisms basedon creating anew taxonomy, orthedefining than philosophy. They were concerned with based solelyonobservable traits rather 1700s were organizing life inaway that was However, otherearlyscientists inthemid serpents, fish, fowl, quadrupeds,andhumans. metals, salts,stones, plants, insects,shells, stages ofexistence: fire, air, water, land,sulfur, Chain ofBeing(shown to theright) lists several Written inFrench, his1745illustration ofthe into increasingly complex stages ofexistence. materials that progressed by theirown force Bonnet believed that adivineBeingcreated reflected common thought at thetime. natural world inaladder-like hierarchy that who studied plants andanimals,organized the In the1700s, Charles Bonnet, aSwissnaturalist The ChainofBeingandaNewTaxonomy 1758 A

Public Domain between peoples’teeth: organisms. Inoneofhismany letters, hewrote abouttheplaque London thefirst ever observations ofmicroscopic single-celled In 1674,Antonie van Leeuwenhoek sent to theRoyal Society of Use thecards to revise your model as necessary. Can your modelexplain thisnew information? ofevolution.2) thetheory 1) theexistence of microorganisms and in light ofthetwo new piecesofinformation: Evaluate your previous modelofthetree oflife ancestor. mechanism for thedescent ofalllivingthingsfrom acommon of evolution which was backed by evidence andproposed a The bookcontained oneofthefirst arguments for thetheory proved to bevery popular, though controversial at thetime. published In 1859,CharlesDarwin common andvaluable scientific tool. Subsequent advancements intechnology madethemicroscope a other scientists showed that microorganisms did,in fact, exist. were initiallymet withskepticism, further investigation by Though hisillustrations (suchastheimage above) andfindings the water (orspittle)like apike does and swift motion,andshotthrough The biggest sort…hadavery strong animalcules, very prettily a-moving. there were many very littleliving wonder, that inthesaidmatter “I thenmost always saw, withgreat oft-times spun roundlike a top.” through thewater. Thesecond sort… Photo: of Amodel an early by microscope used Leeuwenhoek to make first the observations of microorganisms.. Leeuwenhoek’s “Animalcules” The OriginofSpecies

, which 1866 A

(CC BY-SA 3.0) Jeroen Rouwkema Public Domain 1969 A 1990 A Édouard Chatton and Prokaryotes The Discovery of Archaea

As microscope technology improved, more scientists studied In the 1970s, advances in science and technology allowed cells and discovered new species of microbes. In 1938, the scientists to examine genetic information found in DNA or RNA to French biologist Édouard Chatton was the first to characterize determine the relationships between species. Using the reasoning cells as being with a nucleus (eukaryotic) or without a nucleus that groups of organisms with a lot of genetic information in (prokaryotic). Over the next several years, further investigations common are more closely related to each other than others that by scientists popularized Chatton’s work and defined more have less in common, scientists began to reorganize the tree of differences between eukaryotes and prokaryotes. The table below life. indicates whether each organism is a prokaryote or eukaryote. Using the simulated DNA sequences determine how the organisms Revise your previous model of the tree of life to 1) reflect this new are related. Observe how this new information influences the tree piece of information about prokaryotic and eukaryotic cells and 2) of life model. incorporate the newly discovered organisms.

Prokaryotes (cells without nucleus) Eukaryotes (cells with nucleus) Archaeoglobus fulgidus Acinonyx jubatus Bacteroidetes spp. Agaricus bisporus Beggiatoa spp. Bacillariophyceae (class) Borrelia burgdorferi Cupressocyparis leylandii Clostridium difficile Dicksonia antarctica Cyanobacteria spp. Digitaria eriantha Desulfovibrio desulfuricans Equus quagga Enterococcus spp. Eudorcas thomsonii Geobacter metallireducens Giardia intestinalis Haloferax volcanii Gyps africanus Haloquadratum walsbyi Homo sapiens Lactobacillus spp. Liriodendron tulipifera Methanobrevibacter smithii Panthera leo Methanosarcina acetivorans Paramecium aurelia Methylococcus spp. Pyrus communis Rhodopseudonomas spp. Saccharomyces cerevisiae Sulfolobus islandicus Thiobacillus spp. Treponema pallidum Vibrio spp. 1758 B Illustrated interpretation of Linnaeus’ model

Animals Plants © Project NEURON, University of Illinois of University NEURON, © Project 1866 B Protists

Monera Plants Animals Illustrated interpretation of Haeckel’s model Illustrated interpretation of Haeckel’s Illinois of University NEURON, © Project Illustrated interpretationofWoese’s model 1969 B Illustrated interpretation of Whittaker’s model

Eukaryotes Bacteria Animals Plants Fungi Fungi Animals Eukaryotes Origin Plants

Protists Protists

Prokaryotes

Monera Archaea 1990 B © Project NEURON, University of Illinois of University NEURON, © Project © Project NEURON, University of Illinois from thekingdom “Animale.” Doyou recognize any oftheorganism names? Below isatable from anearliereditionof clams. “vermes,” orallotherinvertebrates that were notinsects,suchasworms, slugsand of animalsincludedsubgroups ofmammals,birds, amphibians,fish,insects,and and included“true”plants aswell asfungi,algae, andlichen.Hisclassification animals. Plants were grouped into 24classesbasedontheirreproductive structures Linnaeus arranged life into two maincategories, called “kingdoms”: plants and edition (1758),they were reclassified asmammals. originally classifiedasfishinthe first edition(1735),butinthe tenthand definitive being updated andrevised basedonnew knowledge. For instance, whaleswere over 12,000plants andanimals.Duringhislifetime, the contents were constantly In hisbook publishing hiswork inseveral books. continued to study plants andanimalson expeditions across Europe before show Linnaeusflowers inthe garden and tell himtheirnames.Asanadult,Linnaeus Linnaeus’ interests inbiologyoriginated withplants. Growing up,hisfather would the lion. used today. For example, heusedthegenus andspeciesnameof life forms. Hestarted usingtwo-part namesfor livingthings,amethod that isstill Carl Linnaeusisthefounder ofmoderntaxonomy, thenamingandclassification of Systema Naturae Carolus Linnaeus’ (Latin for “The Systems (Latin ofNature”),for Linnaeusclassified Systema Naturae Systema Naturae showing somegroups Panthera leo for 1758 B

Public Domain Public Domain Public Domain all life evolved. organisms from which time. Haeckel thought theseorganisms were similar to thefirst living or Monera, agroup ofsimplemicrobes poorlyunderstood at the all microscopic organisms. At theoriginoftree heput“Moneres” kingdoms: Plantae, Animalia,andProtista. At thetime, Protista included published in1866,Haeckel depicted atree (seeillustration) withthree der Organismen organization oflife proved influential. Inhis book Haeckel’s contributions to thediscovery ofnew speciesand the around theworld, namingthousandsofnew speciesinhislifetime. Haeckel was anaccomplished illustrator andmadeextensive journeys as sponges andradiolarians, tiny zooplankton withmineral skeletons. University ofJena,Germany, hestudied many invertebrate groups such a zoologist. Duringhislife, includingthetimehe was aprofessor at the Ernst Haeckel was formally trained asamedical doctor before becoming (Germanfor “General morphologyoforganisms”) Ernst Haeckel Ernst Generelle Morphologie

Public Domain 1866 B

Public Domain ingest food. indicate how heorganized speciesbasedonwhether they photosynthesize, absorb, or species aswell astheancestors ofotherkingdoms. Thearrows inthebottom right also suggested that somekingdoms, suchasMonera andProtista, contained present-day (all eukaryotic multicellular organisms). Asseeninhisillustration, the arrangement organisms), Protista (eukaryotic unicellular organisms), Plantae, Animalia,andFungi In Whittaker’s model(shown below), there were five kingdoms: Monera (prokaryotic decaying ordeadmatter whereas plants produce their own food. the past. Theseparation offungi was mostly basedonthe evidence that fungi consume established anew kingdom for fungi,whichhadmostly beengrouped withplants in Chatton andotherscientists whodistinguished prokaryotes from eukaryotes. Healso five-kingdom modelofthetree oflife. Inhismodel,Whittaker incorporated workof In 1969,Robert Whittaker publishedascientific paperinwhichhe proposeda new Robert H.Whittaker Robert 1969 B

Whittaker, R.H. (1969) © National Academy of Sciences. found intheotherdomains. and they have uniquecomponents intheircellmembranes not energy from compounds ranging from sugars to metal ions, such assoilsandhumanintestines. Archaea speciesderive salt lakes, butsincethenthey have alsobeenfound inplaces were inextreme environments suchasvolcanic hotspringsand more similarto eukaryotes. Theearliest discovered archaea studies indicate that archaea have genes andcellular functions monera. Althougharchaea are visuallysimilarto bacteria, classified withbacteria, andbothunderthe category of In previous modelsofthetree oflife, archaea hadbeen contained theBacteria andArchaea kingdoms, respectively. in theEukarya domain,andtheBacteria andArchaea domains Plantae, Animalia,Protista, andFungikingdoms were grouped new model, revised from Whittaker’s five kingdom model.The larger thanakingdom. There were now sixkingdoms inthe Bacteria, andEucarya.” A“domain” isataxonomic group even natural system oforganisms: Proposal for domainsArchaea, 1990 publication hewrote with colleagues, titled “Towards a relationships oforganisms. Theillustration below is from a the first to usemoleculardata to investigate the evolutionary Carl Woese, ascientist at theUniversity ofIllinois, was oneof Carl Woese 1990 B