General Knowledge · Class 7 · Nature and animals
Reptiles and amphibians
A frog can breathe through its skin. Why does that make frogs one of the first animals to suffer when water gets dirty?
Small test at the end: scroll down to the end of this page for five short questions that check what you have learnt. Tap an answer, then press Check answer. Go to the questions ↓
Jump to: Read first · Try it away from the screen · Check it yourself · Check yourself · For teachers
Read first
6 facts. The questions below make you use them, not just remember them.
- Reptiles have dry, scaly skin and breathe with lungs. Most lay eggs on land. Snakes, lizards, turtles and crocodiles are reptiles.
- Amphibians, such as frogs, toads and salamanders, usually begin life in water as tadpoles with gills, then grow lungs. Their thin, moist skin also takes in oxygen, so polluted water harms them quickly.
- The king cobra is the longest venomous snake in the world, up to about 5 metres. It eats mostly other snakes, and the mother builds a nest for her eggs.
- The gharial lives in rivers such as the Chambal. Its long, thin snout is made for catching fish. It is critically endangered.
- Most snakes are harmless. In India, four kinds cause most serious bites: the cobra, the krait, Russell's viper and the saw-scaled viper. After any snakebite, keep still and get to a hospital fast for antivenom.
- Olive ridley sea turtles come ashore in huge groups to lay eggs on the beaches of Odisha, at Gahirmatha and Rushikulya.
Offline
Try it away from the screen
After rain, go out with a grown-up in the evening and listen for frogs. Count how many different calls you can hear. Do not pick the frogs up: salt and soap on our hands can hurt their skin.
Make it on paper. Keep it with you. Nothing to upload.
Check it yourself
Many snakebite "remedies" online are dangerous. Check first-aid advice with a doctor or a government health page, which say: keep calm, keep still, no cutting, no sucking, go to hospital.
Check yourself
Five questions about what this page teaches. Choose an answer and press Check answer, or open "See the answer and why". Nothing is saved or sent: your choices stay on this screen and disappear when you leave or reload the page.
How do you want to answer? You choose, and you can change at any time.
See the answer and why
- A. A monitor lizard Not this one. Lizards are reptiles.
- B. A frog Correct. Yes. It starts life as a tadpole in water.
- C. A turtle Not this one. Turtles are reptiles, even those that live in water.
- D. A crocodile Not this one. A crocodile lives in water but is a reptile, with dry scales.
See the answer and why
- A. Tie a rope very tight above the bite Not this one. A tight rope can cut off the blood and damage the limb.
- B. Put a paste of herbs on it and wait at home to see if it gets worse Not this one. Waiting wastes precious time. Go to hospital.
- C. Keep them calm and still and get to a hospital fast Correct. Yes. Hospitals have antivenom, which saves lives.
- D. Cut the wound and suck the poison out Not this one. Cutting and sucking do not remove venom and cause more harm.
See the answer and why
- A. Digging holes deep in the river bank to sleep in Not this one. Gharials rest on sandy banks; the snout is made for fishing.
- B. Smelling food far away Not this one. Its snout is shaped for catching fish, not for smell.
- C. Breaking open the hard shells of turtles Not this one. Crocodiles with wide jaws can do that; the gharial's jaws are too thin.
- D. Catching fish quickly in water Correct. Yes. A thin snout swings fast through water.
See the answer and why
- A. 5,000 Correct. Yes. 50 × 100 = 5,000 eggs.
- B. 500 Not this one. That is 5 turtles' eggs, not 50.
- C. 50,000 Not this one. That would be 500 turtles.
- D. 150 Not this one. That adds 50 and 100. Each turtle lays 100, so multiply.
See the answer and why
- A. Their eggs have hard shells that trap the dirt Not this one. Frog eggs are soft jelly, with no shell.
- B. They never leave the water Not this one. Many frogs spend much of their time on land.
- C. They take in oxygen and water through their thin skin Correct. Yes. Whatever is in the water can pass into them.
- D. They drink a lot of water Not this one. Frogs do not drink with their mouths; they absorb water through their skin.
For teachers and grown-upsWhere the facts come from, and how to use this round.
Sources and notes
- Snakebite first aid: see the Ministry of Health and Family Welfare / NCDC guidance. Never encourage children to handle snakes.
- Gharial status: IUCN Critically Endangered; the National Chambal Sanctuary spans Rajasthan, MP and UP.
- Safety: the listening walk is with a grown-up, near home.