Karl Hagenbuch's presentation to 2010 class

1. Taxonomy, Classification, and Identification Karl Hagenbuch Department of Biological Sciences San Antonio College

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. 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. 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.

7. Carl von Linné Swedish botanist, zoologist, and physician First to illustrate the usefulness of binomial nomenclature Developed the modern taxonomic hierarchy

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

13. The Pylogenetic Tree

15. Time

16. Species 1 Species 2 Species 3

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

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

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

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

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

26. Leaf Types

27. Leaf Types

28. Leaf Types

29. Leaf Types

30. Leaf Types

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

32. Dichotomous Key 36. Lobes rounded 36. Lobes pointed . . . Quercus macrocarpa . . . . . Quercus buckleyi

33. Thank You It is both an honor and pleasure to speak before the Master Naturalist I wish you all continued success