Classification of Living Things
Classification:• Grouping life based on similarities
• Why classify? To study the vast diversity of life and organize information in a common language.
Species of OrganismsSpecies of Organisms
• There are There are 13 billion13 billion known species of known species of organismsorganisms
• This is This is only 5% of only 5% of allall organisms that organisms that ever lived!!!!!ever lived!!!!!
• New organismsNew organisms are are still being found still being found and identifiedand identified
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Confusion in Using Different Confusion in Using Different Languages for NamesLanguages for Names
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Latin Names are Understood by all Latin Names are Understood by all TaxonomistsTaxonomists
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Taxonomy: the classification and naming of
organisms.• Scientific names are universal.
Early TaxonomistsEarly Taxonomists
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•2000 years ago, 2000 years ago, AristotleAristotle was one of was one of the first taxonomiststhe first taxonomists•Aristotle divided Aristotle divided organisms into organisms into plants plants & animals& animals
Carolus LinnaeusCarolus Linnaeus1707 – 17781707 – 1778
• 18th century Swedish taxonomist
• Classified organisms by their physical structure
• Developed naming system still used today
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Linnaeus’s Hierarchical System
Seven taxonomic categories: Kingdom Animal
Phylum Arthropoda Class Insecta
Order Lepidoptera Family Danaidae
Genus Danaus Species plexippus
Taxon
General term for any one of these categories in the hierarchy.
(Plural of taxon is taxa.)
The system can change as scientists gather new information! (DNA, new discoveries)
• Now we have “Domain” above the Kingdom level
Hierarchy-Taxonomic GroupsHierarchy-Taxonomic Groups
• Domain• Kingdom• Phylum (Division – used for plants)• Class• Order• Family
• Genus• Species
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BROADEST BROADEST TAXONTAXON
Most Specific
hierarchy
http://www.aquatax.ca/images/classificationFigure.jpg
Now come up with your own mnemonic device to remember the order of taxa from domain to species.
D K P C O F G S
• DDumbumb• KKinging
• PPhilliphillip
• CCameame
• OOverver
• FForor
• GGooseberrooseberryy
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Rules for Naming OrganismsRules for Naming Organisms
• The The International Code for International Code for Binomial Nomenclature Binomial Nomenclature contains contains the rules for naming organismsthe rules for naming organisms
• This This prevents duplicatedprevents duplicated names names
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Binomial nomenclature =
two part name:
Genus species• Genus is Capitalized, both words are italicized
or underlined in handwriting.• Latin or Greek describes organism
• Ex: Homo sapiens, Drosophila melanogaster, Toxicodendron radicans, Peromiscus maniculatus
Binomial NomenclatureBinomial Nomenclature
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DomainsDomains
• BroadestBroadest, most inclusive taxon, most inclusive taxon• ThreeThree domains domains• Archaea and EubacteriaArchaea and Eubacteria are are
unicellular prokaryotes (no unicellular prokaryotes (no nucleus or membrane-bound nucleus or membrane-bound organelles)organelles)
• EukaryaEukarya are more complex and are more complex and have a nucleus and membrane-have a nucleus and membrane-bound organellesbound organelles
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ARCHAEA• Probably the 1st cells to evolve• Live in HARSH environments• Found in:
– Sewage Treatment Plants– Thermal or Volcanic Vents– Hot Springs or Geysers that are
acid– Very salty water (Dead Sea;
Great Salt Lake)
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ARCHAEAN
EUBACTERIAmicromovie stars
• Our bodies are covered with them!• Some may cause DISEASE• Found in ALL HABITATS except
harsh ones• Important decomposers for
environment• Commercially important in making
cottage cheese, yogurt, buttermilk, etc.
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Live in the intestines of animalsLive in the intestines of animals
EUKARYAEUKARYA: : Cells have a Cells have a nucleusnucleus!!
Divided into 4 Divided into 4 Kingdoms:Kingdoms:
• ProtistaProtista (protists, algae…) (protists, algae…)• FungiFungi (mushrooms, yeasts …) (mushrooms, yeasts …)• PlantaePlantae (multicellular plants) (multicellular plants)• AnimaliaAnimalia (multicellular animals) (multicellular animals)
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ProtistaProtista•Most are Most are unicellularunicellular•Some are Some are multicellularmulticellular•Some are Some are autotrophicautotrophic, while , while others are others are heterotrophicheterotrophic•AquaticAquatic
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FungiFungi
• Multicellular,Multicellular, except yeastexcept yeast
• Absorptive Absorptive heterotrophsheterotrophs (digest food (digest food outside their outside their body & then body & then absorb it)absorb it)
• Cell walls Cell walls made of made of chitinchitin
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PlantaePlantae
•MulticellularMulticellular•AutotrophicAutotrophic•Absorb Absorb sunlight sunlight to make glucose – to make glucose – PhotosynthesisPhotosynthesis•Cell walls made Cell walls made of of cellulosecellulose
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AnimaliaAnimalia• MulticellularMulticellular• Ingestive Ingestive
heterotrophsheterotrophs (consume (consume food & digest food & digest it inside their it inside their bodies)bodies)
• Feed onFeed on plantsplants oror animalsanimals
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Plantae is divided into about 12 phyla and comprise about 270,000 species. Animalia is split into about 33 phyla and contains about 800,000 species (although this is probably a drastic underestimate of the true figure). Fungi have five phyla and about 100,000 species. Eubacteria have three phyla and a number of species that is difficult even to estimate – some authors suggest 1,000,000,000 (a billion) but even this could be a considerable underestimate! Archaea are poorly known and there are currently three main (and five tentative) phyla that have been created based largely on laboratory cultures (estimates of total phyla range from 18 to 23). The most recent list I can find (1999) contains 209 species. Protista comprise some 20 to 50 phyla and about 23,000+ species.
Dichotomous Keys
• An identification key that contains pairs of contrasting descriptions.
• After each description, a key either directs the user to another pair of descriptions or identifies an object
http://www.amnh.org/learn/biodiversity_counts/ident_help/Text_Keys/arthropod_keyA.htm