Biology module 3

• Classification


  Putting things into groups based on shared characteristics
• Taxonomy


  The science of classifying organisms
• We need to classify the millions of organisms on earth to refer unambiguously and specifically to each organism, see how they might be related, and know when new species are discovered
• Kingdoms


  • Monera (bacteria)
  • Protists (single celled animals and all algae)
  • Fungi (yeasts, moulds and mushrooms)
  • Plants
  • Animals
• Hierarchical system of classification

  1. Kingdom

  2. Phylum

  3. Class

  4. Order

  5. Family

  6. Genus

  7. Species
• To belong to the same group, organisms must have the same features
• Organisms in one group also possess all the features of the parent groups (above) to which they belong
• Organisms in the same group are more related to each other than to those of a higher group
• Species


  Organisms that can interbreed (mate with each other) and have fertile offspring
• Nomenclature


  The set of rules for naming organisms
• Common names


  One organism can have many, can be confusing, sometimes the same name is given to different organisms, not usually used by scientists
• Scientific names


  Binomial nomenclature system (two name naming system) that was accurate and unambiguous, written in Latin
• Binomial name


  • Consists of two names: the genus name followed by the species name
  • The genus always starts with a capital letter; the species with a lower
  • Both names are either underlined or written in italics
  • The names either are Latin or are latin-ised
• Once we know we are referring to an organism the genus name can be shortened e.g. Bubo africanus becomes B. africanus
• Summary of the 5 kingdoms

  • Monera: Simplest organisms, unicellular, not made of true cells
  • Protists: Bigger than bacteria, unicellular or quite big
  • Fungi: Cannot photosynthesise, no roots, stems or leaves
  • Plants: Make their own food by photosynthesis (ferns, conifers, flowering plants)
  • Animals: Chordates (organisms with a nerve cord in their back), fish, amphibians, reptiles, birds, mammals
• Dichotomous keys are a device that can be used to easily identify an unknown organism, consisting of a series of two part statements that describe characteristics of organisms
• Types of keys


  • Branched keys
  • Numbered keys