1. The Characteristics of Living Things
Biologists use six characteristics to classify something as a living thing.
1. Made of Cells
2. Use and Need Energy
3. Adapted to Their Surroundings
4. React to Changes
5. Reproduce
6. Grow and Develop

2. The Characteristics of Living Things
All living things have these six characteristics.
Anything without one of these six characteristics is nonliving.
Living things are called organisms.

3. 1. Made of Cells Organisms are made up of one or more cells.
A cell is the basic unit of structure and function in living things.
Cells = the
“Building Blocks"
of life.

4. 2. Use and Need Energy All organisms need and use energy to live.
Energy gives living things the ability to do work.
Sunlight is the source of energy for most living things.
Plants use the energy in sunlight to make food, and animals get energy by eating plants or other animals that have eaten plants.

5. 3. Adapted to Their Surroundings
Organisms are adapted, or suited, to their surroundings.
All organisms have features that help them survive in their surroundings.
For example: fish have gills

6. 4. React to Changes Organisms react to changes in their surroundings.
Any reaction to change is called a response.
For example: A bright light may cause you to blink.

7. 5. Reproduce Organisms produce more organisms of their own kind.
Reproduction allows organisms to continue living on the Earth.

8. 6. Grow and Develop All organisms grow and develop.
Living things change, or develop, during their lifetimes.
One way organisms change is by growing.
Living things may also change appearance.
For example: tadpoles and frogs

9. Summary
Biologists use six characteristics to classify something as a living thing.
1. Made of Cells
2. Use and Need Energy
3. Adapted to Their Surroundings
4. React to Changes
5. Reproduce
6. Grow and Develop
All living things display all of the above characteristics.