Annelid Segmentation
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An annelid's body divides into repeating segments, each often carrying its own muscles, nerves, and excretory structures, an arrangement supporting precise, localized movement.
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An earthworm's segmented muscles contract in coordinated waves, letting sections of its body move independently as it burrows.
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Annelid segmentation evolved independently from the similar-looking segmentation in arthropods, per molecular evidence placing the two phyla in separate clades.