BiologyIs It Alive? Things That Grow, Make Energy, and Move
Atlas the friendly guide kneels in a sunny garden, pointing at a growing plant beside a smooth round rock and a hopping rabbit, with a fish swimming in a small pond nearby.
- Name three things living things do: grow, use or make energy, and move.
- Classify unfamiliar objects as living or non-living by applying the grow-energy-move rule.
- Explain why a rock is not alive using at least one clue.
- Identify a plant and an animal as living things.
Key terms
- living thing
- Something that grows, uses or makes energy, and moves.
- non-living thing
- Something that does not grow, make energy, or move itself.
- photosynthesis
- How plants make food using sunlight and water.
- energy
- The power a living thing uses to grow and move.
Three Clues That Something Is Alive
Atlas uses three clues to find out if something is living. A living thing grows, it uses or makes its own energy, and it moves on its own. A puppy shows all three: it grew from small to big, it eats food for energy, and it runs around by itself. When you check all three clues together, you can tell living things from non-living things without being fooled.
Plants Make Their Own Food
Plants are living, but they do not eat the way animals do. Instead, plants make their own food inside their leaves using sunlight and water, in a process called photosynthesis. That is how a plant gets energy. Plants even move slowly to turn their leaves toward the sun. A seed grows into a tall plant over time, so plants pass the growing test and the energy test too.
Why Some Things Are Not Alive
A rock and a metal spoon may be hard and shiny, but they are not alive. They do not grow bigger, they cannot make or use their own energy, and they do not move by themselves. A toy car can roll, but only when someone pushes it, so its movement does not count. When something fails the three clues, we know it is non-living, even if it can be pushed to move.
Worked examples
Is a fish in a pond a living thing?
- A fish grows bigger as it gets older.
- A fish finds and eats food to get energy.
- A fish swims through the water on its own.
Answer: Yes, a fish passes all three clues, so it is living.
Is a toy car a living thing if it rolls?
- A toy car only rolls when a person pushes it, not by itself.
- A toy car cannot grow bigger or make its own energy.
- Since it fails the clues, the rolling does not make it alive.
Answer: No, a toy car is non-living even though it can roll.
Activity
Drag each picture into the living box or the non-living box.
Practice
Decide if a tall oak tree is living or non-living and tell why.
Name the three clues that show something is a living thing.
Common mistakes to avoid
- Anything that moves is aliveLiving things move on their own; a toy car only moves when pushed and cannot grow or make energy.
- Plants are not alive because they stay stillPlants are living because they grow, make their own food from sunlight, and even turn slowly toward the sun.
Check your understanding
Which one is a living thing?
Why is a rock NOT a living thing?
A toy car can move when you push it. Is it living?
Which living thing makes its own food from sunlight?
Recap
Living things do three jobs: they grow, they use or make their own energy, and they move on their own. A rock or a metal spoon does none of these, so it is non-living, while puppies, plants, and fish are all alive.
Reflect
What new thing would you like to test with the three clues?