Key Concepts: Characteristics of Life

What Makes Something Alive?

All living organisms share certain characteristics that distinguish them from non-living things.

• Organization: Made of one or more cells
• Metabolism: Chemical reactions to obtain and use energy
• Homeostasis: Maintaining stable internal conditions
• Growth: Increase in size and/or number of cells
• Reproduction: Producing offspring
• Response: Reacting to stimuli in the environment
• Adaptation: Evolving over generations to survive