BACKGROUND:

Students have learned about animals that live on land.  Some animals like frogs, start their life in the water, and then emerge to live on land near water.  Animals have many different habitats in which they live.  

A frog is an amphibian that is at home both on land and in fresh water.  The process that transforms a frog from water to land is called "metamorphosis."  As a tadpole,  they have a very dangerous life.  Many predators like fish, turtles, birds, and even large insects look for the young tadpoles to eat.  Different frog species have different growth rates.  Some become frogs within weeks, however some like the North American bullfrog may take more than a year to fully develop.  The rate of metamorphism is also influenced by temperature of water and other chemical factors.  

Organisms that live in the marine environment must be able to adapt their bodies to the salt water. They also need to have a supply of nourishment similar to organisms that live on land. The ocean usually has nourishment throughout the water as dissolved minerals. Food created by algae is floating within the upper 200 meters of the water column. Water allows organisms to move around with greater ease than on land. Organisms that reside in the ocean live in certain areas of the ocean just like land animals live in certain areas.  Whales for instance have a much larger habitat than an elephant, because the whales can move within the ocean of their birth.

The beach is an area that is half water and half land. Many portions of the beach are covered by water part of the time, so it is not a friendly area to live.

Shallow waters are usually close to the coast. Organisms, like crabs, clams, corals, and seastars reside in this area. Fish can also live in shallow, and deep water. Deep water organisms include porpoises, fishes, and deep water clams.

PROCEDURE:

1. Emphasize with students that there are many habitats in which organisms live in both water and land.  Read "Frog Tales," to students and then discuss the habitat in which frogs live.  You may also go into the metamorphosis from tadpole to frog by using the plastic model.
   
   The "Early Tadpole" is newly emerged from its jelly egg.  The tadpole is fishlike in appearance and has not legs nor can croak.   An "Intermediate Tadpole"  shows small stumps on both sides of its body.  These stumps will later develop into the hind legs.  A "Tadpole with legs,"  has all 4 legs.  Gills are replaced by lungs, mouth and eyes become bigger, and the intestine shrinks.    A "Pre-frog" continues to develop as the tail continuously shrinks.  Its metamorphosis will be complete when the last part of its tail disappears.  
     
2. Provide students with copy of the worksheet.  This  picture shows the different habits of the ocean including deep marine water, shallow marine, and beach environment. Notice that deep water is closest to the bottom of the paper and shallow is toward the beach and land. The view is that of a sail or on a ship in deep water looking towards land.
     
3. Distinguish for students the differences between deep and shallow waters. Have students draw a line to where they think each organism on the worksheet lives or cut out the pictures and have students paste them on. You many want to include other pictures you may have, or stickers of fish or other marine creatures. You may want students to color the different portions of the ocean and land. Make sure you discuss the organisms first and then have the students complete the lab sheet.  You may also want to just have students use a blank piece of paper and cut and paste objects from magazines or pictures that you may have. 
     
4. Answers: Land: tree; Shallow water: snail, crabs, conch, crab, seaweed, and some fish; deep water: fish, ray (some snails and conchs can live in deeper water)