How do we group organisms?

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ClassificatioClassificationn

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•There are There are 13 billion13 billion known known species of organismsspecies of organisms

•This is This is only 5% of allonly 5% of all organisms that ever organisms that ever lived!!!!!lived!!!!!

•New organismsNew organisms are still are still being found and identifiedbeing found and identified

Species of OrganismsSpecies of Organisms

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What is Classification?What is Classification?

ClassificationClassification is the is the arrangement of organisms arrangement of organisms into orderly into orderly groupsgroups based based on their on their similaritiessimilarities

Classification is also known Classification is also known as as taxonomytaxonomy

Taxonomists Taxonomists are scientists are scientists that identify & name that identify & name organismsorganisms

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Benefits of ClassifyingBenefits of Classifying

•Accurately & uniformlyAccurately & uniformly names organisms names organisms

•Prevents Prevents misnomersmisnomers such such as starfish & jellyfish that as starfish & jellyfish that aren't really fish aren't really fish

•Uses Uses same language same language (Latin or some Greek)(Latin or some Greek) for for all names all names

Sea”horseSea”horse”??”??

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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 Latin Names are Understood by all Taxonomistsby all Taxonomists

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Early TaxonomistsEarly Taxonomists

•2000 years ago, 2000 years ago, AristotleAristotle was the was the first taxonomistfirst taxonomist

•Aristotle divided Aristotle divided organisms into organisms into plants & animalsplants & animals

•He He subdividedsubdivided them by their them by their habitathabitat ---land, sea, ---land, sea, or air dwellers or air dwellers

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Early TaxonomistsEarly Taxonomists•John Ray, a John Ray, a

botanist,botanist, was was the first to use the first to use Latin for Latin for namingnaming

•His His namesnames were were very longvery long descriptions descriptions telling telling everything everything about the plantabout the plant

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Carolus LinnaeusCarolus Linnaeus1707 – 17781707 – 1778

•18th century taxonomist

•Classified organisms by their structure

•Developed naming system still used today

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Carolus LinnaeusCarolus Linnaeus

•Called the Called the “Father of “Father of Taxonomy”Taxonomy”

•Developed the modern Developed the modern system of naming system of naming known as known as binomial binomial nomenclaturenomenclature

•Two-wordTwo-word name (Genus name (Genus & species)& species)

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Standardized Standardized NamingNaming

•Binomial Binomial nomenclature nomenclature usedused

•Genus speciesGenus species

•Latin or GreekLatin or Greek

•ItalicizedItalicized in print in print

•Capitalize genusCapitalize genus, , but NOT speciesbut NOT species

•UnderlineUnderline when when writingwriting

Turdus Turdus migratoriusmigratorius

American American RobinRobin

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Binomial NomenclatureBinomial Nomenclature

Which TWO are more closely related?

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Rules for Naming OrganismsRules for Naming Organisms

•The The International Code for International Code for Binomial Nomenclature Binomial Nomenclature contains the rules for contains the rules for naming organismsnaming organisms

•All names must be approved All names must be approved by by International Naming International Naming CongressesCongresses (International (International Zoological Congress)Zoological Congress)

•This This prevents duplicatedprevents duplicated namesnames

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Classification GroupsClassification Groups

•TaxonTaxon ( ( taxataxa-plural) is a -plural) is a category into which related category into which related organisms are placedorganisms are placed

•There is a There is a hierarchyhierarchy of of groups (taxa) from broadest groups (taxa) from broadest to most specificto most specific

•Domain, Kingdom, Phylum, Domain, Kingdom, Phylum, Class, Order, Family, Class, Order, Family, Genus, Genus, speciesspecies

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Hierarchy-Taxonomic Hierarchy-Taxonomic GroupsGroups

DomainKingdom

Phylum (Division – used for plants)

Class Order Family

Genus Species

BROADEST BROADEST TAXONTAXON

Most Specific

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DDumbumb

KKinging

PPhilliphillip

CCameame

OOverver

FForor

GGooseberrooseberryy

SSoup!oup!

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•BroadestBroadest, most inclusive , most inclusive taxontaxon

•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 are more complex and have a nucleus and and have a nucleus and membrane-bound organellesmembrane-bound organelles

DomainsDomains

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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

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EUBACTERIA

•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

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Domain Eukarya is Domain Eukarya is Divided into KingdomsDivided into Kingdoms

•ProtistaProtista (protozoans, algae…) (protozoans, algae…)

•FungiFungi (mushrooms, yeasts …) (mushrooms, yeasts …)

•PlantaePlantae (multicellular plants) (multicellular plants)

•AnimaliaAnimalia (multicellular (multicellular animals) animals)

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ProtistaProtista

•Most are Most are unicellularunicellular

•Some are Some are multicellularmulticellular

•Some are Some are autotrophicautotrophic, , while others are while 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 – Photosynthesis– Photosynthesis

•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 on Feed on plantsplants or or animalsanimals

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TaxonsTaxons

•Most Most generagenera contain a contain a number of similar number of similar speciesspecies

•The genus The genus HomoHomo is an is an exception (only contains exception (only contains modern humans)modern humans)

•Classification is based on evolutionary evolutionary relationshipsrelationships

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Basis for Modern Basis for Modern TaxonomyTaxonomy

•Homologous structuresHomologous structures (same structure, (same structure, different function)different function)

•Similar Similar embryoembryo developmentdevelopment

•Molecular SimilarityMolecular Similarity in in DNADNA, , RNARNA, or , or amino acidamino acid sequence of Proteinssequence of Proteins

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Homologous Structures (BONES in the FORELIMBS) Homologous Structures (BONES in the FORELIMBS) shows Similarities in mammals.shows Similarities in mammals.

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Similarities in Vertebrate Similarities in Vertebrate EmbryosEmbryos

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CladogramCladogramDiagram showing how organisms are related Diagram showing how organisms are related

based on based on shared, derived characteristicsshared, derived characteristics such as feathers, hair, or scalessuch as feathers, hair, or scales

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Primate Primate CladogramCladogram

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Dichotomous KeyingDichotomous Keying

•Used to identify Used to identify organismsorganisms

•Characteristics given in Characteristics given in pairspairs

•Read both Read both characteristicscharacteristics and and either go to another set either go to another set of characteristics of characteristics OROR identify the organismidentify the organism

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Example of Dichotomous Example of Dichotomous KeyKey

1a Tentacles present – Go to 21a Tentacles present – Go to 2

1b Tentacles absent – Go to 31b Tentacles absent – Go to 3

2a Eight Tentacles – Octopus2a Eight Tentacles – Octopus

2b More than 8 tentacles – 32b More than 8 tentacles – 3

3a Tentacles hang down – go to 3a Tentacles hang down – go to 44

3b Tentacles upright–Sea 3b Tentacles upright–Sea AnemoneAnemone

4a Balloon-shaped body–4a Balloon-shaped body–JellyfishJellyfish

4b Body NOT balloon-shaped - 54b Body NOT balloon-shaped - 5