Biology - Classification

• Characteristics of living organisms

  • Nutrition (feeding)
  • Respiration
  • Excretion
  • Movement
  • Irritability (sensitivity)
  • Growth
  • Reproduction
• Nutrition (feeding)


  The process by which living organisms obtain or make food
• Respiration


  The process by which energy is released from food by all living cells
• Excretion


  The process by which waste and harmful substances, produced by the body's metabolism, are removed from the body
• Movement


  A change in the position of a whole organism or of parts of an organism
• Irritability (sensitivity)


  The ability of organisms to detect and respond to changes in their environment or within themselves
• Growth


  A permanent increase in the size and complexity of an organism
• Reproduction


  The process by which living organisms generate new individuals of the same kind as themselves
• Living organisms have seven characteristics in common
• Using similarities and differences between living organisms they can be classified into groups
• Classifications can be done based on visible characteristics, similarities in internal structures, developmental patterns, life cycles and electron microscopic techniques
• Species


  A group of organisms of common ancestry that closely resemble each other and are normally capable of interbreeding to produce fertile offspring
• Categories of classification


  • Species
  • Genera
  • Families
  • Orders
  • Classes
  • Phyla
  • Kingdoms
• Kingdoms


  • Prokaryotes (monera)
  • Protoctists (protist)
  • Fungi
  • Plants
  • Animals
• Prokaryotes (monera)


  • Bacteria and blue-green algae
  • Unicellular organisms
  • Cells have a cell wall
  • Cells lack a true nucleus, the DNA is free in the cell
  • Cells lack other membrane-bound organelles, e.g. mitochondria, chloroplasts
  • Most feed by absorbing food e.g. tuberculosis (TB) bacterium
• Protoctists (protists)


  • Includes the protozoa and algae
  • Most are unicellular, some are simple multicellular organisms that lack any complex development of tissues and organs
  • Cells have a true nucleus surrounded by a membrane and other membrane-bound organelles
  • Protozoans are animal-like and ingest food or absorb food
  • Algae are plant-like, contain chlorophyll and make their own food by photosynthesis e.g. Amoeba, Paramecium, Euglena, Sargassum (seaweed)
• Fungi


  • Includes yeasts, moulds and mushrooms
  • Most are multicellular with a body composed of microscopic threads called hyphae, a few are unicellular
  • Cells have cell walls that contain chitin
  • Cells lack chlorophyll
  • Most reproduce by spores
  • Feed by absorbing food e.g. pin mould
• Plants


  • Multicellular organisms
  • Cells have cell walls made of cellulose
  • Cells contain chlorophyll
  • Make their own food by photosynthesis
  • Stationary organisms
• Animals


  • Multicellular organisms
  • Cells lack cell walls and chlorophyll
  • Feed by ingesting food
  • Most move their whole bodies from place to place
• Plant classification


  • https://www.youtube.com/watch?v=cRCck4niz5o
• Animal classification


  • https://www.youtube.com/watch?v=L6anmd7DnYw