Question

Write the eight general characters of phylum Arthropoda. Mention any two examples.

Answer 1

The characters of the phylum Arthropoda are

• Body is bilateral, triploblastic, and segmented into metameres.
• Body is externally covered by a thick protective chitinous cuticle forming an exoskeleton.
• Each body segment bears a pair of jointed appendages for locomotion. 
• The exoskeleton is cast-off periodically by a process called moulting or Ecdysis.
• Body cavity is filled by blood and is called Haemocoel.
• Digestive System is complete.
• Respiration takes place either with gills, tachea or book lungs.
• Vascular system is open type. The haemolyph has the pigment Haemocyanin.
• Excretion occurs by Malpighian tubules (Insects) or by green glands.
• Development is direct or indirect. The larva undergoes metamorphosis into an adult.
• Examples are Periplaneta Americana (Cockroach) & Poecilocerus pictures (grasshopper).