arthropods

• Arthropods Include

  • Insects
  • Arachnids
  • Myriapods
  • Crustaceans
• Arthropod body structure


  • Invertebrates with a 3-layer exoskeleton (external skeleton)
  • Segmented body
  • Jointed appendages (paired)
• Heteronymous segmentation


  Mostly cephalon, thorax and abdomen
• Arthropod appendages


  • Jointed
• Arthropod body covering


  • Hypodermis
  • Cuticle made of chitin and often mineralised
  • Rigid cuticle replaced by moulting
• Arthropod muscular system

  • Skeletal muscles
• Arthropod digestive system

  • Tubular
  • Variable mouth parts
• Arthropod respiratory system


  • Gills
  • Lung sacs (pallial lung)
  • Tracheal system
  • Skin
• Arthropod nervous system


  • Ladder like or ganglia
• Arthropod sensory system


  • Compound eyes and pigment-pit ocelli
  • Many types of chemical and mechanical sensors mostly based on the setae
• Arthropod reproduction

  • Lay eggs (except scorpions)
  • Sexual (internal fertilisation, metamorphosis, parthenogenesis, heterogenic)
  • Asexual (polyembryony)
• Arthropod subphyla

  • Trilobitomorpha
  • Chelicerata
  • Branchiata
  • Tracheata