groupsarthropods

Arthropods are a phylum of invertebrate animals that are characterized by their exoskeleton, segmented body, and jointed appendages. This phylum is the largest in the animal kingdom, comprising over 80% of all known animal species. The exoskeleton, made primarily of chitin, provides protection and support, but must be shed periodically through a process called molting to allow for growth.

The segmented bodies of arthropods are typically divided into three main sections: the head, thorax, and abdomen, though these may be fused in some groups. The appendages, which are attached to the segments, are also jointed and adapted for a wide variety of functions, including locomotion, feeding, sensing, and reproduction.

Arthropods are found in virtually every habitat on Earth, from the deepest oceans to the highest mountains. They play crucial roles in ecosystems as consumers, decomposers, and prey. Their diversity is immense, and they are commonly classified into four major subphyla: Chelicerata (which includes spiders, scorpions, mites, and horseshoe crabs), Myriapoda (centipedes and millipedes), Crustacea (crabs, lobsters, shrimp, and barnacles), and Hexapoda (insects and their relatives). Each of these groups exhibits unique characteristics and adaptations reflecting their evolutionary history and ecological niches.