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Classification

BIO 2215

Oklahoma City Community College

Dennis Anderson

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Aristotle 384 BC

• Classified organisms as either plants or animals

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Carolus Linnaeus 1707-1778

• Classification system• Taxonomic groups of

related organisms• Binomial nomenclature

(two names)• Homo sapiens• Dermacentor andersoni

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Taxonomic Groups

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Classification of Man

• Kingdom Animalia

• Phylum Chordata

• Class Mammalia

• Order Primates

• Family Hominidae

• Genus Homo

• Species Homo sapiens

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Species

• “Species are groups of actually or potentially interbreeding populations, which are reproductively isolated from other such groups.”

• Reproductively isolated group

Ernst Mayr

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Different Species

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*

* Archaea

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Kingdom Monera or Eubacteria

• Single celled• Prokaryotic• Make or absorb food• Cell wall

– peptidoglycan

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Kingdom Archaea

• Single celled• Prokaryotic• Make or absorb food• DNA

– Similar to Eukaryotic

• Cell wall– Pseudopeptidoglycan

or protein only

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Kingdom Protista

• Single celled• Eukaryotic• Ingest or produce

food

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Kingdom Fungi

• Multicellular• Eukaryotic• Cell wall

– Chitin

• Absorb food

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Kingdom Plantae

• Multicellular• Eukaryotic• Cell wall

– Cellulose

• Produce food– photosynthesis

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Kingdom Animalia

• Multicellular• Eukaryotic• No cell wall• Ingest food• Motile

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Terminology

• Classification– Assigning organisms to

different catagories based on their relationship

• Taxonomy– The science of naming

organisms

• Systematics– Determining evolutionary

relationships of organisms

• Phylogeny– Evolutionary history

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Cladogram

• Evolutionary relationship of a group of organisms

• Each clad (group) share something in common

• Ancestral traits are the oldest

• Derived traits evolved later

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Cladogram for Transportation

• Wheels are the most ancestral

• Wings are the most derived

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Construct a Cladogram

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Gorilla

• Four limbs• Fur• Lost tail

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Tiger

• Four limbs• Fur• Tail

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Lizard

• Four limbs• Tail

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Fish

• Tail

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Chimpanzee

• Four limbs• Fur• Lost tail

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Clad With 4 Limbs

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Clad With Fur

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Clad With No Tail

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Characteristics for Constructing Cladogram

• Tail is the most ancestral

• Four limbs is the oldest derived trait

• Fur is a later derived trait

• Loss of tail is the most derived trait

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Gorilla Chimpanzee

Tiger

Lizard

Fish

Four Limbs

Fur

Tail Lost

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Gorilla Tail?

• How do we know the gorilla lost its tail?

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Gorilla’s Vestigial Tail

Gorilla Human

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Synapomorphy

• A derived character shared by two or more groups.– Fur is a synapomorphy for the various groups

of mammals.– Synapomorphies are used to determine

evolutionary relationships

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Phylogenetic Tree

• Shows evolutionary relationships

• More historical than cladogram

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MyxozoaMyxozoaMyxozoaMyxozoa

ArthropodaArthropodaArthropodaArthropoda AnnelidaAnnelidaAnnelidaAnnelida

MolluscaMolluscaMolluscaMollusca

LophophoratesLophophoratesLophophoratesLophophorates

HemichordataHemichordataHemichordataHemichordata

ChordataChordataChordataChordata

Other Other pseudocoelomatespseudocoelomates

Other Other pseudocoelomatespseudocoelomates

NematodaNematodaNematodaNematoda

PoriferaPoriferaPoriferaPorifera

CtenophoraCtenophoraCtenophoraCtenophoraCnidariaCnidariaCnidariaCnidaria

PlacozoaPlacozoaPlacozoaPlacozoa

PlatyhelminthesPlatyhelminthesPlatyhelminthesPlatyhelminthesNemerteaNemerteaNemerteaNemertea

CiliophoraCiliophoraCiliophoraCiliophoraSarcomastigophoraSarcomastigophoraSarcomastigophoraSarcomastigophora

MicrosporaMicrosporaMicrosporaMicrosporaApicomplexaApicomplexaApicomplexaApicomplexa

MesozoaMesozoaMesozoaMesozoa

EchinodermataEchinodermataEchinodermataEchinodermata

CrustaceaCrustaceaCrustaceaCrustaceaChelicerataChelicerataChelicerataChelicerata

UniramiaUniramiaUniramiaUniramia

ProtochordatesProtochordatesProtochordatesProtochordates

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Fish

Amphibians

Reptiles

Birds Mammals

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Fish

• Fins• Vertebrae• Simple egg• Homodont teeth

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Amphibian

• 4 limbs• Vertebrae• Simple egg• Homodont teeth

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Reptile

• 4 limbs• Vertebrae• Amniotic egg• Homodont teeth

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Bird

• 4 limbs• Vertebrae• Amniotic egg• No teeth• Feathers• Endothermic

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Mammal

• 4 limbs• Vertebrae• Amniotic egg• Heterodont teeth• Fur or hair• Endothermic

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Birds MammalsReptile

Amphibian

Fish

Four Limbs

Amniotic Egg

Endothermic

Fur

Feathers

Vertebrae

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Birds MammalsReptile

Amphibian

Fish

Four Limbs

Amniotic Egg

Endothermic

Fur

Feathers

Vertebrae

• Synapomorphies– Four limbs for amphibians,

reptiles, birds & mammals– Amniotic egg for reptiles, birds

& mammals

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Symplesiomorphy

• Character shared by a number of groups

• Inherited from ancestors older than the last common ancestor.– Symplesiomorphies are not helpful in

determining evolutionary relationships

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Birds MammalsReptile

Amphibian

Fish

Four Limbs

Amniotic Egg

Endothermic

Fur

Feathers

Vertebrae

• Symplesiomorphies– Vertebrae for amphibians,

reptiles, birds & mammals– Four limbs for reptiles, birds &

mammals

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Monophyletic

• A group of all the descendants of a common ancestor

• The common ancestor is in the group

• Example: Mammalia– Ancestor was a

mammal like reptile

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Paraphyletic

• A group of descendants of a common ancestor

• Common ancestor is in the group

• Not all descendants are included

• Example: Reptiles– Does not include birds

and mammals

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Polyphyletic

• A group that has some similarities

• Common ancestor is in not in the group

• Not all descendants are included

• Example: Flying vertebrates

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Tree of Life

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Bilateral Symmetry

7-9

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Fig. 7.9

Sagittal plane

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Anatomical Terms

• Anterior– Head end (front side in upright man)

• Posterior– Tail end (back side in upright man)

• Dorsal– Back side

• Ventral– Belly side

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Anatomical Terms (cont)

• Medial– Close to the middle

• Lateral– Close to the side

• Distal– Away from the main part

• Proximal– Close to the main part

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Anatomical Terms (cont)

• Oral– End with the mouth

• Aboral– Opposite end of the mouth

• Cephalic– Toward head

• Caudal– Toward tail

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Bilateral Symmetry

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Radial Symmetry

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Asymmetry

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The End