Question

What are the possible advantages and disadvantages of a chitinous exoskeleton in arthropods?

Answer 1

Hint: The largest phylum in kingdom Animalia is Arthropoda. The meaning of the term “Arthropoda” is jointed appendages. Arthropoda consists of organisms that have their body covered by a chitinous exoskeleton.

Complete answer: Animals in the phylum Arthropoda have jointed appendages. This phylum includes the class Insecta which are the animals with three pairs of legs. The exoskeleton of arthropods has several advantages and disadvantages. It gives protection to the animals from predators. It also helps the animal to survive in extreme conditions in the surroundings. It also helps these animals to retain water content and prevents the animal from drying out. It also provides protection for the soft and sensitive internal organs from damage. Arthropods are not able to stretch their body because of the exoskeleton. Because of this, they are not able to pass through small pores in order to catch their prey. They need to shed their exoskeleton at constant intervals. During this period, these animals are vulnerable to attacks from their predators. Also, thick covering on the body surface may restrict the normal growth of the underlying tissues. Sensory organs of arthropods include eyes, antennae and statocysts. Examples of insects are beetles, fly, dragonfly, cockroach etc. The chitinous exoskeleton of arthropods can be periodically removed and renewed. This process is known as moulting or ecdysis. This process helps in the growth and expansion of the body of these organisms. The exoskeleton made up of chitin also contains certain proteins and is hardened by calcium carbonate and calcium phosphate.

Note: Molluscs are marine organisms that have a calcareous exoskeleton on their surface. It is made up of calcium carbonate and is secreted by the soft underlying tissue called the mantle. An arthropod's primary internal cavity is a haemocoel, which accommodates its internal organs and through which its haemolymph circulates.