Arthropods are the most diverse group in the animal kingdom. Among them, the evolutionary record holders are the insects, thanks to their ability to adapt to many different ecosystems both in water and on land. The versatility of arthropods is due in large part to chitin, a substance that forms their hard outer covering as well as their wings and other flexible parts. Like cellulose, the building block of plant cell walls, chitin is made of glucose molecules, but it also contains nitrogen, producing a firm structure.
Chitin is the main component of the arthropod’s exoskeleton, the first rigid form to evolve in multicellular organisms: arthropods made chitin as early as 550 million years ago. Secreted by the epidermis, or skin-like,