module 7

• Taxonomy


  The science of naming, describing, and classifying organisms including plants, animals, and even microorganisms
• Systematics


  The study of biological diversity of organisms and their natural evolutionary relationship to other organisms and their environment

  
• Taxonomy and systematics are not clearly separable but are frequently used by biologists interchangeably
• Classification


  The systematic arrangement of organisms in groups or categories according to an established specific criterion

  
• Phylogeny


  The study of evolutionary history and relationship of organisms that descend from one or more ancestry
• Monophyletic Groups


  • Consists of organisms that evolved from one common ancestry
• Polyphyletic Groups


  • Groups of organisms that has several evolutionary lines without common ancestry
• Paraphyletic Groups


  • Consists of organisms that includes a common ancestor, but not all its descendants
• Cladistics


  Classification of an organism based on recency of common ancestry rather than the degree of structural similarity

  
• Cladogram


  A diagram that illustrates evolutionary relationship based on the principles of cladistics

  
• Steps in making a Cladogram

  1. Select groups

  2. Select homologous character to be analyzed

  3. Organize the character states into their correct evolutionary orders
• TAXON CHARACTERS


  • VASCULAR TISSUES
  • SEEDS
  • FLOWERS

  
• Binomial Nomenclature


  A system for giving each organism a two-word scientific name
• Specific Epithet


  The second part uncapitalized part of the scientific name of an organism that follows the genus and often describes a particularity of an organism
• Species


  The basic unit of classification
• Sub-species, Cultivar, Dichotomous Key


  • Sub-species (interbreed) - geographically distinct population that evolved by Natural Selection
  • Cultivar – cultivated varieties of plants. These species are not equivalent to sub-species
  • Dichotomous Key – allows taxonomist to determine the identity of organisms based on keys that consists a series of choices that lead to correct identity
• All the plant groups except mosses have vascular tissues
• Seeds are shared characteristics for all plant groups except mosses and ferns
• Daisy is the only plant that produces flowers
• Pioneers of Plant Classification

  • Theophrastus – classified plants into herbs, shrubs, and trees
  • Dioscorides – his De Materia Medica described 600 species of medicinal plants and was widely used a medical reference for about 1500 years until the end of the Middle Ages
  • Carolus Linnaeus – wrote Species Plantarum, which contains description of plants that were known in his time. He observed 7300 species of plants and provided each plant with a binomial name