Describe Class Diplopoda and Chilopoda in detail?
Members of the Subphylum Crustacea and the Subphylum Uniramia have one major characteristic in common. Both groups have biting jaws, or mandibles. Mandibles are actually modified appendages. Usually the first and/or second pair of appendages anterior to the mandibles are antennae, which are also modified appendages.
Features that distinguish Crustaceans from the other arthropods are their hard exoskeletons, three pairs of mouthparts, two pairs of antennae, and walking legs. The exoskeletons of Crustaceans are impregnated with calcium carbonate (essentially limestone), which makes them very hard. Their mouthparts are appendages that have become modified into jaws for chewing. Their antennae are also modified appendages with sensory hairs, which are used for feeling, and in some cases, filter feeding. Crustacean bodies are characteristically divided into 3 segments: head, thorax, and abdomen. However, in many crustaceans, the head and thorax are fused together into a body unit referred to as a cephalothorax, as seen in crayfish, shrimp, crabs, and lobsters.
Barnacles are sessile crustaceans, which means they live attached to a fixed substrate. The substrate can vary widely, and in fact, could be anything that is submerged most of the time. For instance, barnacles not lonly live on rocks and other attached organisms, but they are found living on mooring ropes, boat hulls, docks, and even whales!
Insects, millipedes, and centipedes comprise the Subphylum Uniramia, which is a very, very large group. Although there are many different species of animals with single branched appendages, they all can be grouped into one of three separate and distinct Classes.