Taxonomy

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Karl Hagenbuch's presentation to 2010 class

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Taxonomy

  1. 1. Taxonomy, Classification, and Identification Karl Hagenbuch Department of Biological Sciences San Antonio College
  2. 2. Taxonomy = the study of naming, describing and classifying organisms, including the rules, theories, principles and procedures Taxon = a group of organisms recognized at any level of a taxonomical hierarchy (e. g. Family, Class)
  3. 3. Classification = the orderly arrangement of organisms into a hierarchal system that is derived from an accumulation of information about the individual organisms, the end result expressing an interrelationship Why? Because it provides humans with a means to address organisms and their relationships to one another Because it allows humans to make inferences about unfamiliar organisms Because it is in our nature
  4. 4. Classification Systems: Artificial = based on obvious or convenient items of information called characters (e.g. flower color, locality). Natural = based on morphological features that give the sense of correlation with those of another organism. (e.g. trees, grasses) Phylogenetic = based on the proposed lineage derived from a wide variety of information.
  5. 5. Aristotle <ul><li>Greek Philosopher </li></ul><ul><li>First to propose a system of classification </li></ul><ul><li>Scala Naturalae </li></ul><ul><li>Two types of animals: </li></ul><ul><li>With blood </li></ul><ul><li>Without blood </li></ul>
  6. 6. Theophrastus <ul><li>Greek Philosopher </li></ul><ul><li>Father of plant taxonomy </li></ul><ul><li>Classification of plants was based on: </li></ul><ul><li>Mode of generation </li></ul><ul><li>Locality </li></ul><ul><li>Size </li></ul><ul><li>Usefulness </li></ul>
  7. 7. Carl von Linné Swedish botanist, zoologist, and physician First to illustrate the usefulness of binomial nomenclature Developed the modern taxonomic hierarchy
  8. 8. Modern Hierarchy (Biological Classification) <ul><li>Domain – Eukarya </li></ul><ul><li>Kingdom – Animalia </li></ul><ul><li>Phylum – Cordata </li></ul><ul><li>Class – Mammalia </li></ul><ul><li>Order – Primates </li></ul><ul><li>Family – Hominidae </li></ul><ul><li>Genus – Homo </li></ul><ul><li>Species – Homo sapiens </li></ul>
  9. 9. <ul><li>Current system recognizes 3 Domains: </li></ul><ul><li>Eukarya: </li></ul><ul><ul><li>Kingdom Animalia </li></ul></ul><ul><ul><li>Kingdom Plantae </li></ul></ul><ul><ul><li>Kingdom Fungi </li></ul></ul><ul><li>Archaea & Bacteria </li></ul><ul><li>The previously recognized Kingdoms of Protista & Monera have been dissolved </li></ul>Modern Taxonomic Hierarchy
  10. 10. Carolus Linnaeus <ul><li>= a two-word name consisting of a generic name and a specific epithet </li></ul>Binomial Nomenclature Specific epithets: Descriptives – Quercus macrocarpa = Oak with big fruit Honorifics – Quercus buckleyi = Oak named for Mr. Buckley Localities – Quercus virginiana = Oak first described in Virginia
  11. 11. Phylogenetic Classification = the evolutionary history of a species or group of species Typically represented as a phylogenetic tree (cladogram) a branching diagram showing the evolutionary relationships among various biological species or other taxa that are believed to have a common ancestor
  12. 13. The Pylogenetic Tree
  13. 15. Time
  14. 16. Species 1 Species 2 Species 3
  15. 18. Plant Classification Current classification systems follow the recognized taxonomic hierarchy, however, there is always some disagreement as to the membership requirements of various taxa The Core
  16. 19. Gymnosperms and Angiosperms <ul><li>Angiosperms </li></ul><ul><li>plants with vascular (circulatory) tissues </li></ul><ul><li>they produce flowers </li></ul><ul><li>reproductive unit is a seed produced within an enclosed ovary </li></ul><ul><li>Gymnosperms </li></ul><ul><ul><li>plants with vascular (circulatory) tissues </li></ul></ul><ul><ul><li>they lack flowers </li></ul></ul><ul><ul><li>reproductive unit is a seed produced on scales in a cone-like structure </li></ul></ul>
  17. 20. Non-vascular Land Plants <ul><li>Non-vascular land plants </li></ul><ul><li>reduced plants that lack vascular (circulatory) tissues </li></ul><ul><li>they neither have flowers nor produce seeds </li></ul><ul><li>reproductive unit is a spore </li></ul>
  18. 21. Ferns <ul><li>Ferns and fern allies </li></ul><ul><li>plants with vascular (circulatory) tissues </li></ul><ul><li>they neither have flowers nor produce seeds </li></ul><ul><li>reproductive unit is a spore </li></ul>
  19. 22. Identification = the assigning of an existing name to an unknown organism Methods Expert assistance – local university, school, museum Comparison method – guide books, internet Dichotomous key – local manuals, floras
  20. 23. Dichotomous Key Keys based on a sequence of pairs of contrasting statements The user chooses the statement that better describes the plant in question Each time a choice is made a number of plants are eliminated Eventually the number of possible identifications is reduced to one
  21. 24. Dichotomous Key 1. Growth habit an herb 1. Growth habit a vine, shrub or tree . . . . . . . . . . . . 2 . . . . 4 4. Growth habit a vine 4. Growth habit a shrub or tree . . . . . . . . . . . . 5 . . . . . . . 7 7. Growth habit a shrub 7. Growth habit a tree . . . . . . . . . . . . 8 . . . . . . . . . . . . 30
  22. 25. Dichotomous Key 30. Leaf arrangement opposite 30. Leaf arrangement whorled or alternate . . . . Fraxinus . 31 31. Leaves simple 31. Leaves compound . . . . . . . . . . . . . . . 32 . . . . . . . . . . . . 44 32. Venation palmate 32. Venation pinnate or reticulate . . . . . . . Washingtonia . . . . . . 33
  23. 26. Leaf Types
  24. 27. Leaf Types
  25. 28. Leaf Types
  26. 29. Leaf Types
  27. 30. Leaf Types
  28. 31. Dichotomous Key 33. Margin entire 33. Margin toothed . . . . . . . . . . . . . . . 34 . . . . . . . . . . . . . . 39 34. Lobes present 34. Lobes absent . . . . . . . . . . . . . . . 35 . . . . . . . . . . . . . . 37 35. Blades palmately lobed 35. Blades pinnately lobed . . . . . Platanus . . . . . . . . . 36
  29. 32. Dichotomous Key 36. Lobes rounded 36. Lobes pointed . . . Quercus macrocarpa . . . . . Quercus buckleyi
  30. 33. Thank You It is both an honor and pleasure to speak before the Master Naturalist I wish you all continued success

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