kingdoms of life

• Key groups of living organisms

  • Animals
  • Plants
  • Fungi
  • Protists
  • Bacteria
  • Viruses
• Animals


  • Multicellular
  • Heterotrophs
  • Reproduce sexually
• Plants


  • Multicellular
  • Autotrophs (get energy from sun via photosynthesis)
• Fungi


  • Some are multicellular, some are unicellular
  • Heterotrophs (get energy from other organisms)
  • Use saprotrophic nutrition (secrete digestive enzymes, absorb nutrients)
  • Some have a mycelium body made of hyphae
  • Some are pathogens that can cause disease
• Protists


  • Mostly unicellular
  • Some are autotrophs (can photosynthesize), some are heterotrophs (consume other organisms)
  • Some are pathogens that can cause disease (e.g. malaria)
• Bacteria


  • Unicellular
  • Some can photosynthesize but don't have chloroplasts
  • Most feed off other living or dead organisms
  • Extremely numerous, more species than all other kingdoms combined
  • Some are pathogens that can cause disease, but most are harmless or helpful
• Viruses


  • Not cells, just tiny particles
  • Have a protein coat surrounding genetic material (DNA or RNA)
  • Can only reproduce by infecting and using other living cells
  • Always act as parasites and cause harm to the host organism
• Eukaryotes (animals, plants, fungi, protists) have DNA in chromosomes and a nucleus, while prokaryotes (bacteria) have loose DNA and no nucleus
• Viruses are much smaller than even prokaryotic cells, around 10-100 times smaller
• There are an estimated 5-10 million different species of animals on Earth
• There are around 300,000 known species of plants
• Fungi can be either multicellular or unicellular
• Most protists are unicellular
• Scientists estimate there are more species of bacteria than all other kingdoms combined
• Viruses are not considered living organisms, they are just particles that can only reproduce by infecting other cells
• Examples of viruses include influenza, tobacco mosaic, HIV, and COVID-19