Biologists use six key characteristics to determine if something is considered a living thing: 1) being made of cells, 2) using and needing energy, 3) being adapted to their surroundings, 4) reacting to changes, 5) reproducing, and 6) growing and developing. All living things exhibit all six of these characteristics, while nonliving things lack at least one of these characteristics.

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 of life.

4. 2. Use and Need
Energy
 All organisms
need and use
energy to live.
 Energy is 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 change 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
 Living things
change, or develop,
during their
lifetimes.
 One way organisms
change is by growing.
 Living things may also
change in appearance.
• For example: tadpoles
and frogs
 All organisms grow
and develop.

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.