1. 17.1 The Linnaean System of Classification KEY CONCEPT Organisms can be classified based on physical similarities.

2. 17.1 The Linnaean System of Classification Linnaeus developed the scientific naming system still used today. TaxonomyTaxonomy is the science of naming and classifying organisms. taxonA taxon is a group of organisms in a classification system. White oak: Quercus alba

3. 17.1 The Linnaean System of Classification Binomial nomenclatureBinomial nomenclature is a two-part scientific naming system. –uses Latin words –scientific names always written in italics –two parts are the genus name and species descriptor

4. 17.1 The Linnaean System of Classification genusA genus includes one or more physically similar species. –Species in the same genus are thought to be closely related. –Genus name is always capitalized. A species descriptor is the second part of a scientific name. –always lowercase –always follows genus name; never written alone Tyto alba

5. 17.1 The Linnaean System of Classification Scientific names help scientists to communicate. –Some species have very similar common names. –Some species have many common names.

6. 17.1 The Linnaean System of Classification Which of the following is correctly written in the binomial nomenclature system? A.Red wolf B.Canis lupus C.Ailurus Fulgens D.kingdom

7. 17.1 The Linnaean System of Classification Linnaeus’ classification system has seven levels. Each level is included in the level above it. Levels get increasingly specific from kingdom to species.

8. 17.1 The Linnaean System of Classification

9. The Linnaean classification system has limitations. Linnaeus taxonomy doesn’t account for molecular evidence. –The technology didn’t exist during Linneaus’ time. –Linnaean system based only on physical similarities.

10. 17.1 The Linnaean System of Classification Physical similarities are not always the result of close relationships. Genetic similarities more accurately show evolutionary relationships.

11. 17.2 Classification Based on Evolutionary Relationships KEY CONCEPT Modern classification is based on evolutionary relationships.

12. 17.2 Classification Based on Evolutionary Relationships Cladistics Cladistics is classification based on common ancestry. Phylogeny is the evolutionary history for a group of species. –evidence from living species, fossil record, and molecular data –shown with branching tree diagrams called CLADOGRAMS

13. 17.2 Classification Based on Evolutionary Relationships Cladistics is a common method to make evolutionary trees. –classification based on common ancestry –species placed in order that they descended from common ancestor

14. 17.2 Classification Based on Evolutionary Relationships A cladogram is an evolutionary tree made using cladistics. –A clade is a group of species that shares a common ancestor. –Each species in a clade shares some traits with the ancestor. –Each species in a clade has traits that have changed.

15. 17.2 Classification Based on Evolutionary Relationships Derived charactersDerived characters are traits shared in different degrees by clade members. –basis of arranging species in cladogram –more closely related species share more derived characters –represented on cladogram as hash marks FOUR LIMBS WITH DIGITS Tetrapoda clade 1 Amniota clade 2 Reptilia clade 3 Diapsida clade 4 Archosauria clade 5 EMBRYO PROTECTED BY AMNIOTIC FLUID OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW FEATHERS & TOOTHLESS BEAKS. SKULL OPENINGS BEHIND THE EYE DERIVED CHARACTER

16. 17.2 Classification Based on Evolutionary Relationships FOUR LIMBS WITH DIGITS Nodes represent the most recent common ancestor of a clade. Clades can be identified by snipping a branch under a node. Tetrapoda clade 1 Amniota clade 2 Reptilia clade 3 Diapsida clade 4 Archosauria clade 5 EMBRYO PROTECTED BY AMNIOTIC FLUID OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW FEATHERS AND TOOTHLESS BEAKS. SKULL OPENINGS BEHIND THE EYE NODE DERIVED CHARACTER CLADE

17. 17.2 Classification Based on Evolutionary Relationships Molecular data may confirm classification based on physical similarities. Molecular data may lead scientists to propose a new classification. Molecular evidence reveals species’ relatedness. DNA is usually given the last word by scientists.

18. 17.1 The Linnaean System of Classification Dichotomous keys Dichotomous keys help to identify organisms based on their physical characteristics

19. 17.1 The Linnaean System of Classification Use a dichotomous key

20. 17.4 Domains and Kingdoms KEY CONCEPT The current tree of life has three domains.

21. 17.4 Domains and Kingdoms Classification is always a work in progress. The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae Animalia Plantae

22. 17.4 Domains and Kingdoms Classification is always a work in progress. The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae –1866: all single-celled organisms moved to kingdom Protista Animalia Protista Plantae

23. 17.4 Domains and Kingdoms Classification is always a work in progress. The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae –1938: prokaryotes moved to kingdom Monera –1866: all single-celled organisms moved to kingdom Protista Animalia Protista Plantae Monera

24. 17.4 Domains and Kingdoms The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae Classification is always a work in progress. –1938: prokaryotes moved to kingdom Monera –1866: all single-celled organisms moved to kingdom Protista Monera –1959: fungi moved to own kingdom Fungi Protista Plantae Animalia

25. 17.4 Domains and Kingdoms The tree of life shows our most current understanding. New discoveries can lead to changes in classification. –Until 1866: only two kingdoms, Animalia and Plantae Classification is always a work in progress. –1938: prokaryotes moved to kingdom Monera –1866: all single-celled organisms moved to kingdom Protista –1959: fungi moved to own kingdom –1977: kingdom Monera split into kingdoms Bacteria and Archaea Animalia Protista Fungi Plantae Archea Bacteria

26. 17.4 Domains and Kingdoms The three domains in the tree of life are Bacteria, Archaea, and Eukarya. Domains are above the kingdom level.

27. 17.4 Domains and Kingdoms Domain Bacteria includes prokaryotes in the kingdom Eubacteria (true bacteria). –one of largest groups on Earth –can be single celled or clustered (colonies) –cell wall, cell membrane, and a plasmid (circular DNA) –classified by shape, need for oxygen, and how they obtain food

28. 17.4 Domains and Kingdoms Domain Archaea includes prokaryotes in the kingdom Archaea. –live without oxygen (anaerobic) –get their energy from inorganic matter or light –can be single celled or clustered together –known for living in extreme environments –structured cell wall, cell membrane and rRNA

29. 17.4 Domains and Kingdoms Domain Eukarya includes all eukaryotes: –Kingdom Protista –diverse groups of unicellular or multicellular organisms –can be described as: –plant-like (algae) autotrophs –animal-like (protozoa) heterotrophs –fungus-like (spore producing) heterotrophs

30. 17.4 Domains and Kingdoms Domain Eukarya includes all eukaryotes: –Kingdom Plantae –multicellular, –can not move –have cell walls –carry out photosynthesis (autotrophic)

31. 17.4 Domains and Kingdoms Domain Eukarya includes all eukaryotes: –Kingdom Fungi –unicellular or multicellular –contain cell walls –heterotrophic (decomposers) –live in moist environments –can not move

32. 17.4 Domains and Kingdoms Domain Eukarya includes all eukaryotes: –Kingdom Animalia –multicellular –have distinct body plans –contain complex organ systems –heterotrophic –capable of movement at some stage –either invertebrates or vertebrates