- Approximately 7000 living species
- brittle stars, sea stars, sea urchins, sand dollars, sea biscuits, and sea cucumbers are echinoderms
- all echinoderms live in the ocean
- all species covered with spines or bumps, though sea cucumber’s bumps are under the skin
- bodies have a five-part radial symmetry
- no brains
- most have tube feet for moving and feeding
- mouth on underside
Reading: pages 146-155 of The Seaside Naturalist. Read a page or two at a time; there’s a lot of material in this section.
After reading a bit, stop and take a look at the echinoderms on the Encylopedia of Life web site.
Extra reading: The most written-about echinoderm, at least in the US, is the sea star, and you’ll likely find several books at your library on the subject. One good one is Sea Stars, by Kris Hirschmann (Thomson/Gale, 2003). Older children (say, aged 9 and up) can read this one, or an adult can read it aloud. Lots of good info here! For instance, Sea stars are both predator and prey. What do they eat? How do they eat? How do they eat? What eats them?
- the area on the beach between high and low tide, also known as the intertidal zone
- Divided into spray zone, high tide zone, middle tide zone, and low tide zone
Reading: Enchanted Learning. A good illustration of the various parts of the intertidal zone.
Watching: Short film at National Film Board of Canada “The Intertidal Zone”
- excellent places to study marine life
- features of rocky shores
- depend on the exchange of water as tides rise and recede
- each pool is a complete ecosystem
- lower tide pools in the intertidal region are best places for study
A good guide to some nonfiction picture books about tide pools at the blog Wild Rose Reader. Includes At Home in the Tide Pool and The Seaside Switch.
At another good site, also written by kids, you’ll find some instructions for making a simple tide pool viewer.
Right now it’s too cold for my 10-year-old son to enjoy our beach, which is on the Long Island Sound. (I don’t mind so much, though.) Before we do go in the summer, I hope to get ahold of Marine Animals of Southern New England and New York, by Howard Weiss. A favorite, more general field guide is the National Audubon Society Field Guide to New England, which covers a lot of ground from geology to flora and fauna.
1.Plan a trip to the beach at low tide. Do you see the various parts of the intertidal zone? Look for echinoderms. What is the most likely place to find them?
2. Find a tide pool. What do you see there? Does anything live there permanently? What changes when the tide comes in? Is life here cushy or hard?
3. A goofy project for home: After reading about echinoderms and observing them at the shore, choose one type and write (or dictate to someone) a first-person story from its perspective. Illustrate it if you like. For instance, you could start out, “I am a sea star. I am a bottom dweller.” (I got this idea from another book, Jellies, by Twig C. George, who writes much of the text in second person. “If you were a jellyfish, you would have two choices–to go up or down.” Not about echinodermata, but a good book with cool photos! An interesting choice of point of view, too.)
Extra reading: A fun book of poetry about marine life is Sea Stars: Saltwater Poems, by Avis Harley (Boyds Mills, 2006). The poems are short, and the photographs are great.
Also, don’t miss this interview with an invertebrate marine biologist, at the blog Growing with Science.
from Susan Thomsen, guest contributor