Taxonomy Reflects Evolutionary

History

Section 15.4

Classification/Taxonomy

Classification the grouping of objects for practical purposes.

Ex: Taxonomy the identification,

naming and classification of species. The science of classification of organisms

Aristotle(384-322 BC) One of the earliest taxonomists Living things two groups Plants &

Animals Plants herbs, shrubs, and trees Animals live on land , water and air**artificial system didn’t work, birds live

on land, water & air **Listed 500 species, today at least 5

million of which only 1.5 have been named

Carolus Linnaeus(1707-1778)

Developed a method still used today Selected characteristics that led to more

natural groupings of species Identified species by two names genus &

species Binomial nomenclature The system also groups organisms into

different categories starting from the smallest- species to the largest-kingdom

Classification Categories

Kingdom broadest Phylum Class Order Family Genus Species most specific

Classification-Dichotomous Key

Series of paired statements that describe the presence or absence of certain characteristics

Animals No wings(4)

Wings(1-3)

1 2 3 4

Feathers (1,2)

No Feathers (3)Black & white(1)

Pink (2)

(1-4)

Phylogenetic Tree

A diagram that reflects the evolutionary relationship between species

Each branch point represents a common ancestor.

Phylogenetic Tree

Clade/ Cladistics Clade Each

evolutionary branch in a phylogenetic tree.

Cladisticsthe method used to determine the sequence of branching in a phylogenetic tree

Cladograms A phylogenetic diagram that

specifies the derived characters of clades

Comparing Classification Schemes

Linnaeus two kingdom system, system prevailed for 200 yrs

Whittaker(1969) Five Kingdom system

Three Domains

Reevaluation of the five-kingdom system three domain system

2 Domains of Prokaryotes Bacteria, Archaea1 Domain of Eukaryotes Eukarya