This page contains a Flash digital edition of a book.
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


7


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24