BiologySorting Living Things From Nonliving Things
Lumi kneels in a sunny backyard garden, holding a bright green seedling in one hand and a smooth gray rock in the other, looking curiously at both while a butterfly lands nearby on a flower.
- Identify at least three things that all living things need to survive.
- Sort common objects into living and nonliving groups.
- Explain why a plant and an animal are both living things.
- Compare a living thing and a nonliving thing and describe one difference.
Key terms
- living thing
- Something that grows, uses energy, and can make more of itself.
- nonliving thing
- Something that does not grow, use energy, or reproduce.
- energy
- The power a living thing uses to grow and move.
- reproduce
- To make new living things of the same kind.
The Three Tests For Life
Scientists use a simple checklist to decide if something is alive. A living thing must do all three of these jobs: it grows and changes over time, it gets energy by eating or making food, and it can make more of itself. If even one of these is missing, the thing is not alive. Using all three tests together keeps us from being tricked by tricky examples like fire or moving toys.
How Living Things Get Energy
Every living thing needs energy to stay alive, but they get it in different ways. Animals find and eat food, like a rabbit eating grass or a dog eating its dinner. Plants are different: they make their own food inside their leaves using sunlight and water. This is called photosynthesis. Even though plants and animals get energy in different ways, both of them truly need energy, which is one big sign of being alive.
Why A Rock Is Nonliving
A rock might sit in your garden for years, but it is not alive. A rock does not grow on its own, it cannot eat food or make food for energy, and it cannot make baby rocks. It fails all three tests for life. Many nonliving things, like chairs, water, and toys, also fail these tests. Remember that being natural or being old does not make something alive; only the three tests decide.
Worked examples
Is a sunflower a living thing?
- A sunflower grows from a small seedling into a tall plant, so it grows.
- A sunflower makes its own food from sunlight and water, so it gets energy.
- A sunflower makes seeds that grow into new sunflowers, so it can reproduce.
Answer: Yes, a sunflower passes all three tests, so it is living.
Is a wooden chair a living thing?
- A chair does not grow bigger over time.
- A chair cannot eat or make its own food for energy.
- A chair cannot make more chairs by itself.
Answer: No, a chair fails all three tests, so it is nonliving.
Activity
Sort each thing into the Living or Nonliving bin by dragging it.
Practice
Decide if a buzzing honeybee is living or nonliving and explain why.
Name the three tests a thing must pass to be alive.
Common mistakes to avoid
- Anything that moves is aliveMoving alone does not mean alive; a thing must also grow, get energy, and reproduce to count as living.
- Old or natural things are livingBeing old or made by nature does not make something alive; rocks are natural but cannot grow, eat, or reproduce.
Check your understanding
Which of these is a living thing?
A fire can grow bigger and needs air. Does that make fire a living thing?
What do ALL living things need to survive?
Recap
Living things must pass all three tests: they grow, they get energy by eating or making food, and they can make more of themselves. A nonliving thing like a rock or chair fails these tests, so it is not alive.
Reflect
What is one tricky thing you were not sure was alive, and why?