Teacher sheet · Ages 10–11 · about 45–50 minutes
Two ways of life: amphibians and reptiles
Lesson page: echoesof.science/school/reptiles-amphibians/ages-10-11/ · Pupil worksheet: echoesof.science/school/reptiles-amphibians/ages-10-11/print/
Learning aims
- Describe the main features of amphibians and reptiles.
- Describe metamorphosis in frogs.
- Explain why reptile eggs can be laid on land.
- Explain ectothermy and carry out a fair test with a line graph.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: a frog and a lizard both sit in the sun. Why might the frog not stay there long? |
| 10 min | Read the text; draw the frog life cycle. |
| 20 min | Basking test and graph (start it first if the sun is out). |
| 5 min | Reptile, amphibian or both? game. |
| 5 min | Quiz. |
Materials for the experiment
- Two identical small plastic bottles (e.g. 330 ml)
- Water at room temperature
- Two thermometers
- A sunny windowsill or a sunny spot outside, and a shady spot
- Timer
Safety: Never look straight at the sun. If you work outside, wear a hat and stay with your group. Use plastic bottles, not glass. Wipe up spills.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| Cold-blooded animals always have cold blood. | Ectotherms get their heat from the surroundings; a basking lizard can be warm. |
| All amphibians lay eggs in ponds. | Most frogs do, but eggs only need to stay moist; some are laid in damp places. |
| Turtles are amphibians because they swim. | Turtles have scales and lay shelled eggs on land: they are reptiles. |
Worksheet answers
- Eggs in jelly in water → tadpole with gills and tail → tadpole grows legs, loses tail and gills, grows lungs → adult frog.
- Reptile skin is dry, with keratin scales and a waxy layer that stops water loss; amphibian skin is moist, lets water and gases through and is used for breathing.
- Changed: sun or shade. Measured: water temperature every 5 minutes. Same: bottles, amount of water, starting temperature, thermometers, times.
- The sun bottle warmed faster. A lizard is an ectotherm: it warms up by taking in heat from the sun before it can be active.
Quiz answers
- What does the word 'amphibian' mean? Double life. Most amphibians start in water and live on land as adults.[1]
- Which group has the most kinds of amphibian? Frogs and toads. There are almost 6,000 kinds of frog.[1]
- What happens during metamorphosis? A tadpole loses its gills and tail and grows legs. The tadpole changes into a frog.[1]
- Why can reptiles lay eggs on dry land? Their eggs have a shell and membranes that stop them drying out. Frog eggs in jelly would dry out on land.[2][3]
- What is an ectotherm? An animal whose body heat comes mainly from its surroundings. Reptiles and amphibians are ectotherms.[3]
- Which of these is a reptile? A tortoise. Turtles and tortoises are reptiles.[2]
Going further
Find out which reptiles and amphibians live wild in your country. Which are protected? Make a fact card for one of them.
Sources used in this lesson
- [1] Biology 2e, 29.3 Amphibians (OpenStax (Rice University)): reliability High
- [2] Biology 2e, 29.4 Reptiles (OpenStax (Rice University)): reliability High
- [3] Reptiles and amphibians: introduction, distribution and life history (U.S. National Park Service): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/reptiles-amphibians/sources/
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