PYLUM: Arthropoda

• What does the term "Arthropoda" mean?

  'Jointed appendages/legs'
• Why are arthropods considered the most advanced phylum of invertebrates?

  They exhibit complex body structures and adaptations.
• How many identified species are there in the phylum Arthropoda?


  More than one million.
• What types of animals are included in the phylum Arthropoda?


  • Insects
  • Spiders
  • Crustaceans (crabs and crayfish)
  • Centipedes
  • Millipedes
• In what types of habitats can arthropods be found?

  In sea water, fresh water, on land, in the soil, and in the air.
• What is the composition of the hard exoskeleton of arthropods?

  Chitin (polysaccharide) and protein.
• How is the exoskeleton of crustaceans different from that of other arthropods?

  It is hardened with calcium carbonate.
• What is segmentation in arthropods?

  • Evident in the animals of this phylum
  • Similar segments occur in more primitive forms
  • As complexity increases, the number of segments decreases
  • Some segments may fuse to form specialized body sections
• What are the three body regions of insects?

  A head, thorax, and abdomen.
• What is the cephalothorax in spiders?

  A fused head and thorax region.
• What is meant by "jointed appendages" in arthropods?

  Appendages with movable joints that allow for efficient movement.
• How do jointed appendages benefit arthropods compared to worms?

  They enable arthropods to move more quickly and efficiently.
• What type of symmetry do arthropods exhibit?

  Bilateral symmetry.
• What is cephalisation in arthropods?

  A high degree of concentration of sensory organs and nervous tissue in the head region.
• What type of eyes do most arthropods have?

  One pair of compound eyes and/or one or a few pairs of simple eyes.
• What type of digestive system do arthropods possess?

  A complete gut with a mouth and anus.
• What type of body organization do arthropods have?

  They are triploblastic and coelomate.
• How does the coelom function in arthropods?

  It is greatly reduced and does not serve as a hydrostatic skeleton due to the presence of an exoskeleton.
• What is the term for the blood-filled space in arthropods?


  Haemocoel.