ScienceLiving and non-living things
What makes a thing alive? Seven signs that separate a sparrow from a stone.
Look around you. A dog, a neem tree and an ant are living things. A chair, a stone and a bicycle are non-living things. But what exactly is the difference? A car moves and a fire grows, yet neither is alive. Scientists look for a set of signs. A living thing shows all of them.
The signs of life
- They need food. Animals eat plants or other animals. Green plants make their own food using sunlight.
- They breathe (respire). Living things take in air and use it to get energy from food. Fish take in the air dissolved in water through gills. Plants exchange gases through tiny openings in their leaves.
- They grow. A kitten becomes a cat and a seed becomes a tree. This growth happens from inside the body.
- They move on their own. Animals walk, fly or swim. Plants move too, but slowly: a sunflower turns towards the sun and the leaves of the touch-me-not fold when touched.
- They feel and respond. You pull your hand away from a hot pan. A plant bends towards light. A change that a living thing responds to is called a stimulus.
- They get rid of waste. The body removes what it does not need, as sweat, urine and the air we breathe out. This is called excretion.
- They reproduce. Living things produce young ones of their own kind. Birds lay eggs, cows give birth to calves and plants grow from seeds.
Why a car is not alive
A car moves, but someone has to drive it. It "eats" petrol, but it does not grow and it cannot produce baby cars. A crystal of sugar can grow in a solution, but only by more sugar sticking on the outside; it does not breathe or feel. A thing must show all the signs together to be called living.
Things that were once alive
A wooden table is non-living, but its wood came from a tree that was once alive. A dry leaf, a cotton shirt and a leather belt also came from living things. Things such as rocks, water and air were never alive.
How living and non-living things depend on each other
Living things cannot survive without non-living things. Plants need sunlight, air, water and soil. Animals need air, water and a place to live. All of these together make up our environment, which is why we must keep air, water and soil clean.
Key terms
- Respiration
- using air to release energy from food
- Stimulus
- a change around us that a living thing responds to
- Excretion
- removing waste from the body
- Reproduction
- producing young ones of the same kind
Try it yourself
Take a sheet of paper and make three columns: living, non-living, once living. Walk around your home for ten minutes and write at least eight things in each column. Check each "living" entry against all seven signs.
Quick questions
Answer in your head or on paper first, then tap to check.
Name any four signs of living things.
Any four of: need food, respire, grow, move, respond, excrete, reproduce.
Is a plant a living thing? Give one reason.
Yes. It grows, makes food, responds to light and produces seeds.
Why is a moving car not a living thing?
It cannot move by itself, does not grow and cannot reproduce.
Give two examples of things that were once living.
A wooden table, a dry leaf, a cotton cloth, paper.
This is a simple explanation to help you understand. For examinations, read the same chapter in your prescribed textbook. Last checked: 11 November 2026.