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Unit 2.1

Classification

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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

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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• DNA

– Single, circular chromosome

• Cell wall– peptidoglycan

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Kingdom Archaea

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

– Similar to Eukaryotic – One or more linear chromosomes

• Cell wall– Pseudopeptidoglycan

(protein only) • Extremophiles

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Kingdom Protista

• Single celled• Eukaryotic• May be autotrophic or

heterotrophic• May possess cell wall

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Kingdom Fungi

• Multicellular• Eukaryotic• Cell wall

– Chitin

• Absorb food - Heterotrophic

• Non-motile

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Kingdom Plantae

• Multicellular• Eukaryotic• Cell wall

– Cellulose

• Produce food via photosynthesis - Autotrophic

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Kingdom Animalia

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

Heterotrophic• Motile

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Terminology

• Classification– Assigning organisms to

different categories 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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Gorilla Chimpanzee

Tiger

Lizard

Fish

Four Limbs

Fur

Tail Lost

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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Bilateral Symmetry

7-9

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Fig. 7.9

Sagittal plane

Anatomical Terms

• Anterior– Towards the head end

• Posterior– Towards the tail end

• Dorsal– Back side

• Ventral– Belly side

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Anatomical Terms (cont)

• Distal– Away from the main

part

• Proximal– Close to the main part

• Cranial– End with the mouth

• Caudal– Opposite end of the

mouth30

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Bilateral Symmetry

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Radial Symmetry

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Asymmetry

The End

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