Once Upon a Seashore:
A Curriculum for Grades K-6

At High Tide, The Table Is Set

Concepts
  1. At high tide the seashore is covered with seawater.
  2. At high tide seashore animals move around in search of food.
  3. At high tide seashore animals must protect themselves from predators.

Understandings
The children will be able to 1) describe seashore animals at high tide, 2) identify conditions at high tide and at low tide, 3) describe feeding behaviour at high tide.

Materials
Transparency "Dock Piling at High Tide"

The Table is Set All Year Long
Coastal waters produce a rich harvest of food year-round. In spring and summer, the main crops are microscopic plants called phytoplankton, and luxuriant growths of seaweeds. They thrive in the shallow, sun-warmed waters providing food for countless diners.

Marsh grasses and seaweeds grow in spring and summer, too, but only a small portion is eaten directly. Most grasses and seaweeds die in the fall, decay, and become the food of many coastal animals through winter until the plant plankton and seaweeds bloom again in the spring.

At High Tide, The Table is Set
At low tide, or when out of seawater, most inter-tidal animals hide in their shells, among moist seaweeds, under rocks and in crevices or in tidal pools. Without water, there's no food to eat and no shield from the sun. But when the tide returns and covers the plants and animals, the feast is on!

Filter feeders such as clams, mussels, and barnacles strain tiny plankton from the water and scavengers such as crabs and beach hoppers eat decaying matter washed up on shore. Herbivores such as periwinkles, limpets, and chitons graze, like cows, on the thin film of green algae that covers the rocks. Carnivores, of course, dine on their fellow animals.

Procedures
  1. Who has been to the seashore when the tide is high?
  2. When the tide is high, how does life change for seashore animals?
  3. Show the transparency "Dock Piling at High Tide." Find the same animals in both pictures. Some of these animals look very different. Ask the children to compare a sea star at high tide and at low tide. A sea anemone. A barnacle. A periwinkle. A tube worm.
  4. Ask the children to look closely at the sea star in the two pictures. What is different? (The tube feet show at high tide). What is different about the barnacle? (The feathery plume or rake shows at high tide). What is different about the tube worm? (The feathery plume shows at high tide). Etc.
  5. If you were a seashore animal capable of rapid movement such as a sea star, purple shore crab, or shrimp, would you be able to move easier at high tide or at low tide? (High tide). Why? (The water allows you to move around. You would be lighter. You could swim, etc.).
  6. If you were a sea star would you search for prey at high tide or at low tide? Why? (You would be lighter and you could use your tube feet to move, find prey, and open up clams).
  7. If you were a barnacle cemented to a rock, would you feed at high tide or at low tide? (High tide). Why? (At high tide the seawater or plankton soup covers you).
  8. If you were a periwinkle or limpet would you feed at high tide or low tide? (At high tide you would graze on seaweeds or the algae covered rocks, but at low tide you would close up tight to protect yourself from predators and drying out).
  9. If you were a sea anemone attached to a rock, would you feed at high tide or at low tide? (High tide). Why? (You could open up and wave your tentacles. At high tide a shrimp or small fish might swim by).
Preview Pages

cover

overview of each chapter
page 12, 13

sample lesson, hermit crabs
page 67, 68, 69

sample lesson, low tide
page 123, 124, 125

sample lesson, high tide
page 126, 127, 128

sample lesson, a trust walk
page 240