Sea stars
Sea stars are probably the most readily recognised type of echinoderm,
being generic starfish such as the cushion star (Patiriella
regularis), the seven-arm star (Coscinasterias calamaria)
and the eleven-arm star (Astrostole scabra). Echinoderms
generally have five-pointed radial symmetry but as with most
situations in nature, there are exceptions to the rule! Sea
stars have a range of feeding strategies, with cushion stars
generally (but not always!) being detrital feeders and larger
stars such as the 7 armed star being very effective predators.
They can feed by everting their stomachs and digesting their
food externally.
Did
you know?
Sea stars, as with other echinoderms have a water-vascular system,
which manipulates water pressure within their body so that they
can move, remove detritus from their dorsal surfaces, respire
and feed.
