Sea Stars

Sea stars are radially symmetric marine animals belonging to the phylum Echinodermata, renowned for their remarkable ability to regenerate lost arms and their exotic diversity of forms and colors. Commonly called starfish, these creatures inhabit ocean floors from shallow tide pools to abyssal depths, playing vital roles in food webs and marine ecosystems.

Most sea stars possess five arms radiating from a central disc, though some species boast dozens. Their bodies lack a brain but feature a sophisticated nervous system distributed throughout their arms, allowing independent movement and sensation. Beneath their bumpy or spiny skin lies a hydraulic system of tube feet that enables locomotion and feeding.

Sea stars are carnivorous predators and scavengers. Some specialize in consuming coral or mollusks—the crown-of-thorns sea star is infamous for devastating coral reefs. Others are detritivores, cleaning the ocean floor. Their resilience is legendary: many species can regenerate an entire body from a single severed arm, a process involving cellular differentiation guided by mysterious biological signals.

Threatened by ocean acidification, warming waters, and disease, sea star populations face unprecedented challenges. Understanding their genetics and ecology becomes increasingly urgent for ocean conservation.

Related

Echinoderms, Tide pools, Coral reefs, Ocean acidification, Regeneration (biology), Marine conservation