Jointed appendages Arthropod appendages are jointed. Appendages became specialized for feeding, sensing, locomotion, sperm transfer, and spinning silk. Respiratory structures Special tubes called tracheas supply oxygen directly to body tissues. This allows high metabolic rates and sustained activity, as in flight. The compound eye provides a wide angle of vision.
Many individual units allow motion perception.
Division of labor Larval stages concentrate on feeding and growth. Adults specialize in dispersal and reproduction. The process of change from larva to adult is called metamorphosis. Spiders are keen predators that trap insects in their webs produced as silk strands from the abdomen. These are important components of food webs and serve as human food also.