TaxonomyThe science of classifying organisms.

ClassifyTo arrange according to similarities or differences.

Why classify?

Biologists use classification to organize living things into groups so that the organisms are easier to study.

We classify to make our lives easier.

History of Taxonomy

Aristotle

• Simple classifications• Used common names• Plant or animal?• If an animal does it have blood? does it– Fly– Swim– Walk/Crawl

• DISCUSSION QUESTION - Using Aristotle's 3-group system (based on movement), name 2 animals that would fit each of the 3 groups.

Problems with this system?

Some animals can walk, swim, and fly

What technology helped scientist improve the classification system?

Microscope -1600s

Carolus Linnaeus 1700s

• Described organisms with two word names, instead of polynomials

• Developed binomial nomenclature• First word = Genus name (Capitalized)• Second word = species name (lowercase)

scientific name– Example Canis lupusAlways italicized or underlined

Why binomial nomenclature?

• Binomial - 2 name• Nomenclature – naming system• Much easier than a 10+ word name under old

“polynomial system”• Same name no matter where you go (Latin)• Less confusion

Devil Cat

Ghost Cat

Mountain Lion

Screaming Cat

Puma

Florida Panther

Cougar

Felis concolor

Taxonomic Hierarchy

• Names organisms and their relationships from very broad to very specific

Classification of Living Things

Milky waySolar System

EarthU.S.Ohio

WestervilleMainsail Dr.

283

DomainKingdom

PhylumClassOrderFamily

GenusSpecies

Three Domains of Life

There used to be 2, why do you think there are 3 now?

Domain Archaeabacteria: Life's Extremists...! Archaea are found in the harshest environments on Earth, and are the oldest known

organisms on Earth, appearing in the fossil record over 3.6 BILLION years ago (3,600,000,000 years ago!)

Domain Bacteria (or Eubacteria):is familiar to most people when associated with human or animal disease. However, most bacterial species do not (and cannot) cause disease. Most species even play beneficial roles for humans by producing antibiotics and food.

Domain Eukarya

A single-celled or multicellular organism whose cells contain a distinct membrane-bound nucleus.

(Organism’s cell has a nucleus.)

DomainKingdom

PhylumClassOrderFamily

GenusSpecies

Pro = before

Why has taxonomy changed throughout history?

Do you think it will continue to change?

Prokaryotes

• We are now filling out our charts

Archaea

• Unicellular prokaryotes • Autotrophs • Cell wall

EukaryotesEu = trueHave membrane bound nuclei

•Most are unicellular

Phylum examples

• Chordata Cord Chordates Hollow dorsal nervous chord, notochord, pharyngeal slits, endostyle, post-anal tail about 100,000+ Cnidaria Stinging nettle Coelenterates Nematocysts (stinging cells) about 11,000 Ctenophora Comb bearer Comb jellies Eight "comb rows" of fused cilia about 100 modern species Cycliophora Wheel carrying Symbion Circular mouth surrounded by small cilia

52

Classification of Humans

• Kingdom Animalia• Phylum Chordata• Class Mammalia• Order Primates• Family Hominidae• Genus Homo• Species sapiens

Is your table filled out?

Don’t lose it!!!