Students will learn about the life cycle by exploring tadpoles.
For live animal lesson, add the following materials:
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Frogs are amphibians. After hatching, they go through metamorphosis. They start as tadpoles that have gills and a tail and they swim like fish. As they develop, they begin to grow hind legs first. These legs are visible on the outside. Then the front legs begin to grow inside; you can see the bulge and watch them eventually ‘pop’ out. Over time, tadpoles start to absorb their tail and take on the appearance of an adult frog. Female frogs lay from 600 to 1,200 eggs in a jelly-type mass. If a tadpole survives, it takes approximately 12 to 16 weeks for it to fully develop into an adult frog.
If you order live tadpoles, you must use pond water or water that has been treated. Tadpoles are very fragile and chlorine will kill them. Keep extra treated water on hand at all times. When cleaning water, you can use a baster to suck up some of the dirty water. Replace dirty water with treated water that has been sitting for at least a day and is the same temperature as the aquarium water. Change and replace water every two to three days. Some food can become toxic if left for three or more days. It is best not to change ALL of the water. Change 50 to 75 percent of the water.
Intended Learning Outcomes
1. Demonstrate a positive learning attitude.
6. Communicate clearly in oral, artistic, written, and nonverbal form.
Observation, description, data collection, investigation
Invitation to Learn
Give a riddle similar to this example: “What animal has a double life, can swim like a fish when it is young, and has front legs that grow inside its body and then come out?”
* If you have the live tadpoles, read this book as the authors intended. Students should make journal entries about the real tadpoles once a week. They should record descriptions, pictures, and observations.
Tadpoles usually develop faster in warmer water. Have two aquariums and place them in different places in the classroom. Use a temperature gauge to check the temperature. Keep one aquarium in a warmer spot (do not heat the tadpoles, only place them in a warmer spot in the classroom). Students should predict what they think will happen. They should add that information to their journals. They should also record whether they are correct or wrong, how they know, and how their predictions are changing.
Have students describe the tadpoles to a family member once a week. They can write the description at school and take it home. Have students ask family members what other animals
Go through metamorphosis?
Live in the water?
Are born from eggs?
The class can make a chart to answer the homework question and include every student's answers.
Are students making predictions of what comes next? Are their journal sentences and pictures matching what is actually happening? Are students spending time observing the tadpoles?