ALL FINALS

• Aristotle was the first to classify organisms almost 2000 years ago into two categories: plants and animals
• Aristotle's classification of animals


  • Land dwellers
  • Water dwellers
  • Air dwellers
• Aristotle's classification of plants

  • Herbs
  • Shrubs
  • Trees
• Flaws in Aristotle's system: Many organisms were placed in groups to which they had no real relationship, the use of common names was very confusing, and many new organisms were being discovered and needed to be classified
• Linnaean Classification System

  Based on structural similarity, placed organisms in a particular group and assigned a scientific name (binomial nomenclature)
• Two-kingdom System


  Divided all organisms into kingdoms: plant and animal, each subdivision called a phylum or division, further subdivided into 7 levels: Kingdom, Phylum, Class, Order, Family, Genus, Species
• As the knowledge of microbial life exploded, it became apparent that a division into two kingdoms cannot be maintained
• Three-kingdom System


  Kingdoms: Protista, Plantae, Animalia, based on morphological complexities, division of labor, and mode of nutrition
• Four-kingdom System

  Added kingdom Monera for prokaryotic protists, retained eukaryotic protists in kingdom Protoctista
• Five-kingdom System

  Based on evolutionary relationship of phenotypic characteristics: cell type, level of organization, and nutritional type
• Six-kingdom/Three-domain System


  Domains: Bacteria, Archaea, Eukarya, with kingdoms within each domain
• Eight-kingdom System

  Divided kingdom Protista into better-defined kingdoms
• Seven-kingdom System

  Two Empires and seven kingdoms, based on ultrastructural characteristics and rRNA sequences
• The Five Kingdoms of Life

  • Monera
  • Protista
  • Fungi
  • Plantae
  • Animalia
• Kingdom Monera

  • All prokaryotes, lack membrane-bound organelles, reproduce asexually, have 70S ribosomes
• Kingdom Protista

  • Eukaryotic, solitary or colonial unicellular, aquatic, photosynthetic or non-photosynthetic, have membrane-bound organelles, reproduce sexually and asexually
• Kingdom Fungi

  • Heterotrophic, filamentous vegetative body, cell wall made of chitin, reproduce asexually and sexually
• Kingdom Plantae

  • Primarily autotrophic, multicellular, photosynthetic, reproduce sexually with alternation of generations
• Kingdom Animalia

  • Multicellular, wall-less eukaryotic cells, tissue and organ-system organization, ingestive nutrition, sexual reproduction with meiosis
• Evidences used in modern taxonomy and classification

  • Morphology
  • Cellular organization
  • Evolutionary relationships
  • Biochemical similarities
  • Genetic similarities
  • Embryological similarities
• Phylogenetic tree


  Depicts the evolutionary relationships between various groupings of species
• Dichotomous key


  A tool for identifying organisms based on observable characteristics, using a series of paired statements
• Nomenclature


  The system of scientific naming of organisms
• The International Code of Botanical Nomenclature (ICBN) provides rules and recommendations for the naming of plants, fungi and related organisms
• The generic epithet is a noun, the species epithet is an adjective that describes characteristics of the organism
• nigrum

  Black colour
• sativa

  For cultivated one
• esculenta

  Edible one
• These names are not used always and species may be a Pronoun, e.g., americana, indica, benghalensis, etc.
• hastata, cordata, sagitata


  Name characterizing shape of a leaf (character of plant)
• pangteyana, sahnia


  Name of other scientist to whom the plant is dedicated
• Phenetics (or taximetrics)


  The study of relationships among a group of organisms on the basis of the degree of similarity between them, be that similarity molecular, phenotypic, or anatomical
• Cladistics

  The study of the pathways of evolution
• While phenograms represent similarities between organisms, cladograms represent kinship relationships
• Phenetic analysis


  • Phenetic techniques include forms of clustering and ordination to reduce variation displayed by organisms to a manageable level
  • In practice, this means measuring dozens of variables, and then presenting them as two- or three-dimensional graphs
• Cladistic analysis

  • Members of a group share a common evolutionary history, and are "closely related," more so to members of the same group than to other organisms
  • These groups are recognized by sharing unique features which were not present in distant ancestors, called synapomorphies
  • Plesiomorphy is an ancestral trait, Apomorphy is a derived trait, Autapomorphy is a derived trait only found in one group, Synapomorphy is a derived trait shared by two or more groups
• Cladists make the following assumptions: 1) Any group of organisms are related by descent from a common ancestor, 2) There is a bifurcating pattern of cladogenesis, 3) Change in characteristics occurs in lineages over time
• Phylogenetic tree


  Illustrates how taxa (groups of organisms) evolved in a specific order as life diversified and branched out from a common ancestor
• Cladogram


  Visual representation of related characteristics in various organisms
• Monophyletic taxon


  A clade of organisms that includes their most recent common ancestor and all the living and extinct descendants