What are signs of life?

How can you tell if something is living? While there are over 100 characteristics of living things, the following are 8 key traits to look out for.

1. Living things are organized.

  • This means that living things are made up of one or more cells.
  • In more complex organisms, cells come together to make tissues, tissues come together to make organs, and organs come together to make systems.

2. Living things grow.

3. Living things reproduce.

  • A simple bacterial cell, for example, makes an identical copy of itself through the process of mitosis.
  • A more complex living thing such as a mammal creates a new organism through the process of sex.

4. Living things die.

5. Living things move.

6. Living things process energy.

  • For example, humans eat and convert food into energy to power the body.

7. Living things get rid of waste.

  • For example, mammals produce feces and expel carbon dioxide from their lungs.

8. Living things are sensitive to their environment.

  • For example, some plants grow towards light.