Introduction to Biological Classification

BIOLOGICAL CLASSIFICATION

  • Biological classification, or scientific classification in biology, is a method by which biologists group and categorize organisms by biological type, such as genus or species.
  •  Biological classification is a form of scientific taxonomy but should be distinguished from folk taxonomy, which lacks a scientific basis.
  •  Modern biological classification has its roots in the work of Carolus Linnaeus, who grouped species according to shared physical characteristics.
  •  These groupings have since been revised to improve consistency with the Darwinian principle of common descent.
  • Molecular phylogenetics, which uses DNA sequences as data, has driven many recent revisions and is likely to continue to do so.
  •  Biological classification belongs to the science of biological systematics.
  •  “Five kingdoms- Robert Whittaker recognized an additional kingdom for the Fungi.
  •  The resulting five-kingdom system, proposed in 1969, has become a popular standard and with some refinement is still used in many works and forms the basis for newer multi-kingdom systems.”
  • It is based mainly on differences in nutrition; his Plantae were mostly multicellular autotrophs, his Animalia multicellular heterotrophs, and his Fungi multicellular saprotrophs.
  •  The remaining two kingdoms, Protista and Monera, included unicellular and simple cellular colonies.
  • KINGDOM ->  PHYLUM  ->  CLASS ->   ORDER ->  FAMILY ->  GENUS ->   SPECIES 

        (King             Philip              Came          Over           For            Good        Spaghetti)

Here is the beginning of a Living Things Tree Web.

  •  Kingdom Monera                                                       
  •  Kingdom Protista
  •  Kingdom Fungi
  •  Kingdom Plant
  •  Kingdom Animalia

 

  •       The hierarchy of biological classification's eight major taxonomic ranks
  • PHYLA
    •  Each of the 5 kingdoms is then divided into several phyla.
    •  The phyla category begins to break-up the animals, plants, bacteria etc. into smaller groups.
    •  A few examples of phyla in the animal kingdom are: Arthropoda (spiders, insects, crustaceans); Mollusca  (clams, snails, squid); and the most common phylum, Chordata - animals with backbones (mammals, reptiles, fish, amphibians, birds).
  •  CLASS
    •  The Class breaks up animals into more groups that you would find familiar. 
    •  The phylum Chordata is broken down into several classes.
    •  Here are four examples of the classes found in the phylum called Chordata: Reptilia (reptiles), Mammalia  (mammals), Aves (birds), and Amphibia (amphibians).
  • ORDER
    •  Each class is made up of orders.
    •  The Mammalia class can be broken down into Primates (monkeys), Perissodactyla (horses, zebras) Rodentia (rats, mice), Chiroptera (bats), Insectivora (moles), Carnivora (dogs, cats, weasels), Artiodactyla (cows), Proboscidea (elephants) and several more.
  •  FAMILY
    • The order Carnivora can be broken down into several families such as Ursidae (bears), Mustelidae (weasels, wolverines), Canidae (dogs), Felidae (cats), and Hyaenidae (hyaenas, wolves) to name a few.
  •   GENUS
    •  The category next to Family is the Genus.
    •  The family Felidae (cats), for example, can be broken down into Acinonyx (cheetah), Panthera (lion, tiger), Felis (domestic cats), etc.
  •  SPECIES
    •  After genus is the final category of Species.
    •  The genus Panthera (lion, tiger) is broken down into Panthera leo (lion) and Panthera tigris (tiger).