: They are as ubiquitous in the ocean as insects are on land, filling roles as predators, scavengers, and vital food sources for larger animals.
: A few groups have adapted to life on land, including woodlice (sowbugs/pillbugs) and certain land crabs, though they still require damp environments to breathe through their gills. Common Examples
: A hard, chitinous outer shell that provides protection and structural support. Many species further harden this shell through calcification . crustacean
: Their bodies are usually segmented, often featuring a cephalothorax (a fused head and trunk). Diverse Habitats and Ecological Roles
are a vast and diverse group of invertebrate animals : They are as ubiquitous in the ocean
: Tiny but essential links in the marine food web, supporting massive animals like whales.
: Highly valued in global fisheries for human consumption. Many species further harden this shell through calcification
belonging to the subphylum within the phylum Arthropoda . With over 45,000 to 52,000 known species distributed worldwide, they range from familiar seafood like to microscopic copepods and terrestrial woodlice . Key Characteristics