Classification

• CLASSIFICATION


  • Organisms can be classified into groups by the features (similarities and differences) they share.
  • An organism or a group of similar organisms may be grouped together due to common features they share.
  • Any organism or group of organisms must be compared with descriptions of what is already known to classify them in a specific group.
  • The descriptions are often organized as a dichotomous key which provides as briefly and as reliably as possible the most obvious characteristics, in pair. Very often they are set out as a dichotomous key with opposing pairs of characters.
• WHY DO WE CLASSIFY?

  • Useful in providing information on evolutionary relationships among organisms.
  • To study organisms systematically
  • To ease communication between scientists
  • Recognize similarities between living things (in terms of genetic materials (DNA), biomolecules, etc)
• Aristotle was the first scientist to group organisms based on physical characteristics
• Carolus Linnaeus (1707 - 1778) a Swedish botanist, came up with the current system, which is still being used today.
• THE TAXONOMIC PROCESS


  1. (1) obtaining a suitable specimen (collecting, preserving .....)

  2. (2) comparing the specimen with the known range of variation of living things, using a dichotomous key

  3. (3) correctly identifying the specimen if it has been described, else identified as a new species. If the specimen is new, naming is done according to internationally recognized codes of nomenclature (Binomial system of naming species)

  4. (4) determining the best position for the species in existing classifications and determining what revision the classification may require as a consequence of the new discovery
• CLASSIFICATION GROUPS


  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species
• THE 5 KINGDOMS


  • Kingdom of Protists
  • Kingdom of Monerans
  • Kingdom of Fungi
  • Kingdom of Plants
  • Kingdom of Animals
• KINGDOM PROTISTA


  • Kingdom Protista contains all eukaryotes that are NOT Plants, Animal, or Fungi.
  • Kingdom Protista includes mostly unicellular and a few simple multicellular EUKARYOTES (e.g seaweeds).
  • Eukaryotic cells have nuclei and organelles that are surrounded by membranes.
  • The cells of multicellular protists are not specialized to perform specific functions in the organisms.
  • mostly aquatic
• KINGDOM FUNGI


  • Fungi are eukaryotes
  • Most are multicellular; Only unicellular algae is Yeast
  • The cells of fungi have cell walls that contain a material called chitin.
  • no chlorophyll
  • Fungi are heterotrophic and obtain their nutrients by releasing digestive enzymes into a food source. The digested particles are then absorbed by the fungi (saprophytic nutrition).
  • Fungi act either saprophytic (as decomposers) or as parasites (lives and feed on other living otganisms) in nature.
  • Kingdom Fungi includes molds, mildews. mushrooms, and yeast.
• Complex organisms


  • Flowering plants
  • Non flowering plants
  • Invertebrates
  • Vertebrates
• Vertebrates


  • Mammals
• Animals


  • Invertebrates
  • Vertebrates
• Living Organisms


  • Animalia
  • Protist
• Virus


  Simple organisms
• Envelope


  • Made of an outer lipid layer and an inner protein layer surrounding the capsid
• RNA


  • The influenza virus has a total of strands of RNA. Many viruses contain DNA rather than RNA
• Capsid


  • The proteins in a capsid are determined by the genes in the virus
• Projections


  • The spikelike projections on the viral envelope help the virus recognize and attach to a host cell
• Reverse transcriptase


  • Enzyme found in retroviruses like HIV that allows them to convert their RNA genome into DNA
• Glycoprotein


  • Protein found on the surface of some viruses like influenza that helps them attach to host cells
• Envelope


  • Outer lipid layer of some viruses
• Viruses attack a host cell in a tissue culture
• Viruses are simple organisms
• Living things


  • Plants
  • Bacteria
  • Animals
  • Protoctista
  • Fungi
• Animals


  • Vertebrates
  • Invertebrates
• Vertebrates


  • Fishes
  • Amphibians
  • Reptiles
  • Birds
  • Mammals
• Invertebrates


  • Arthropods
  • Myriapods
  • Crustaceans
  • Arachnids
  • Others
• Arthropods


  • Segmented invertebrates that have an exoskeleton and jointed appendages
  • Many have antennae
  • Found in nearly all habitats
  • Body completely covered by a cuticle exoskeleton made of chitin
  • Molt their exoskeleton as they grow
• Crustaceans


  • Have five pairs of legs
  • Live near or on the ocean floor
  • Live on land and water
  • Have antennae