Classification

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Classification

• Chapter 18(M)

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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

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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 didnt work, birds live on
  land, water air
• Listed 500 species, today ? at least 5 million of
  which only 1.5 have been named

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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

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Classification Categories

• Kingdom? broadest
• Phylum
• Class
• Order
• Family
• Genus
• Species? most specific

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Classification-Dichotomous Key

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

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1 2 3 4
No wings(4)
Animals
No Feathers (3)
(1-4)
Wings(1-3)
Black white(1)
Feathers (1,2)
Pink (2)
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Phylogenetic Tree

• A diagram that reflects the evolutionary
  relationship between species
• Each branch point represents a common ancestor.

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Phylogenetic Tree
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Clade/ Cladistics

• Clade? Each evolutionary branch in a phylogenetic
  tree.
• Cladistics?the method used to determine the
  sequence of branching in a phylogenetic tree

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Cladograms

• A phylogenetic diagram that specifies the derived
  characters of clades

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Comparing Classification Schemes

• Linnaeus? two kingdom system, system prevailed
  for 200 yrs
• Whittaker(1969)? Five Kingdom system

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Three Domains

• Reevaluation of the five-kingdom system ? three
  domain system
• 2 Domains of Prokaryotes
• Bacteria, Archaea
• 1 Domain of Eukaryotes
• Eukarya

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