1. Botany CH 17 – Classification of Organisms

2. Taxonomy

3.  The science of classifying and naming organisms  Each group is called a taxon (pl. taxa) What is Taxonomy ?

4. Metadata Taxonomy

5. Bloom’s Taxonomy

6. iPhone Taxonomy

7. Advertising Taxonomy

8. Early Taxonomy ( 384 – 322 BC )  Aristotle, a philosopher of Greek origin, began the organization process  He used only 2 taxa  It was very inefficient as common names varied from place to place

9. Early Two Taxa System

10.  Linnaeaus, a Swedish botanist devised a system based upon form and structure  His goal was to join “ similar to similar”  His original system had 7 levels 1 2 3 4 5 6 7 Linnaean System ( circa 1750 ) EMPIREKINGDOMCLASSORDERGENUSSPECIESVARIETY

11.  This system still had 7 levels – but now slightly different Linnaean – with an early change EMPIREKINGDOMCLASSORDERGENUSSPECIESVARIETY KINGDOMPHYLUMCLASSORDERFAMILYGENUSSPECIES

12. Levels of Classification

13.  While older systems were based on observed features  Recent DNA sequencing has uncovered natural relationships  So the system was re-organized into an 8 –level format 1 2 3 4 5 6 7 8 Taxonomic Reshuffle

14. greater dissimilarity greater similarity (least alike) (most alike ) D OMAIN K INGDOM P HYLUM C LASS O RDER F AMILY G ENUS S PECIES Modern System

15. E NGLISH N AME G ROUP L ATIN / G REEK N AME animals KINGDOM Animalia chordates PHYLUM Chordata vertebrates SUB - PHYLUM Vertebrata mammals CLASS Mammalia primates ORDER Primates hominids FAMILY Hominidae human GENUS Homo wise SPECIES sapiens

16.  So the DNA sequencing ( think Genome Project) data forced the change to a 3-domain system  This system is not based solely on observable features  These domains are:  Domain Bacteria  Domain Archaea  Domain Eukarya The 3 Domain System

17.  These are prokaryotic organisms  They lack a true nucleus  They have cell walls  They reproduce by binary fission Domain Bacte ria

18.  These are also prokaryotic organisms  They lack a true nucleus  They have distinctive cell membranes  They reproduce by binary fission Domain Archaea

19.  These are the eukaryotic organisms  They have membrane bound organelles – including a membrane bound nucleus Domain Eukarya

20. The 6 Kingdom System BacteriaArchaeaEukarya EubacteriaArchaebacteriaProtistaPlantaeFungiAnimalia

21.  Eubacteria - means “true bacteria”  Archaebacteria – means “ ancient bacteria” Prokaryotic Kingd oms

22.  Protista  Neither plants, animals, or fungi  Identified by what they are not  Fungi  Get their nutrition by absorption  Plantae  Most are autotrophic  Animalia  Develop from embryos and have symmetry Eukaryotic Kingd oms

23. Naming System

24.  Linnaeus also developed a naming system for the organisms in his classification system  It was called binomial nomenclature  The “binomial” meant that every organism would be identified by its genus and species Linnaeus Revisited

25.  The genus name begins with an uppercase letter  The species name is always lowercase  Both would be underlined or italicized Rana pipiens ( Northern leopard frog ) Escherichia coli ( Enteric rod bacteria ) Binomial Nomenclature

26. Systematics

27.  Systematics is a way to classify organism by their relationship (evolutionary)  Systematics is based on inferences that are founded on homologous structures Systematics

28.  Homologous structures are organs or bones that appear in completely different organisms  It is these homologous structures that allows scientists to infer that these organisms had a “shared” ancestor Homologous Structures

29. Examples

30.  The inferred (evolutionary) history of a single species is known as phylogenetics  The prefix phylo means “tribe” or “race”  The suffix genetics means “origin” Phylogenetics

31.  Similarities between fossils and living species Phylogenetic Evidence

32.  Similarities in embryo  development ontogeny recapitulates phylogeny Phylogenetic Evidence

33.  Similarities in chromosome sequences Phylogenetic Evidence

34.  Similarities in homologous structures Phylogenetic Evidence

35.  All phylogenetic trees are hypothetical  They will change with every new discovery The Result Phylogenetic Tree

36. Cladistics

37.  Cladistics is a system that uses shared characters and derived characters for its grouping  It was conceived in 1966 by a German biologist  Cladistics infers that organisms that share a derived characters inherited it from a common ancestor Cladistics

38.  A shared character is a feature that all members of the group have in common Examples: hair in all mammals OR feathers in all birds  A derived character is an advanced trait that evolved within the group being analyzed Example: loss of a tail Cladistics

39.  A clade is a group of organisms that share a common ancestor  The derived character is used to group those organisms into the clade The Clade

40.  Amphibians, turtles, lizards, snakes, crocodiles, birds and mammals have or historically had four limbs  Fossils show that snakes did have limbs  Some modern snakes retain rudimentary limbs  Four limbs = a shared derived character and was inherited from a common ancestor for this clade of vertebrates A Vertebrate Clade

41. Vertebrate clade

42. Botany CH 17 – Classification of Organisms End