cushion sea star
Slow, but Fierce An orange sea star creeps along the seafloor.
It’s on the hunt. Under its body, hundreds of sticky tube feet ripple and move it forward. It finds a mussel. T e mussel slams its shell
shut, but it’s no match for the sea star. T e sea star’s feet grab it. Slowly, they pull and pry the shell open a crack. T e sea star belches out its stomach. It slides
its stomach into the shell. Stomach juices turn the mussel into goo. T e sea star absorbs the goo, then sucks its stomach back in. T e sea star and its dinner are invertebrates. Yet they belong to diff erent groups.
Fantastic Five Sea stars belong to the phylum Echinodermata.
T e name means “spiny skin.” T eir tough skin protects their soſt bodies. T e animals in this group have other things
in common, too. Instead of blood, seawater moves through their bodies. T at’s what makes the sea star’s tube feet work. T ey also have a body based on the number five. Many have five arms, five legs, or five sets of mouthparts. Take the sea urchin. Spines cover and
protect a sea urchin’s round body. Five pointy teeth ring its mouth. T e urchin uses its teeth to scrape algae from rocks.
sea urchin
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