What Is Life? Characteristics of Living Things

Contributor: Hannah Brooks. Lesson ID: 12074

In an age of robots, avatars, animatronics, holograms, Pixar, and self-driving cars, it's getting hard to tell what is actually alive and what isn't. Learn what classifies an organism as being alive!


Life Science

learning style
Auditory, Kinesthetic, Visual
personality style
Otter, Beaver
Grade Level
Middle School (6-8)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

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  • How can you tell if something is alive or not?
  • Cars can move, produce waste, and are made of parts, so do these characteristics make them alive?

Whoa, creepy question! Let's find out!

Compare these images:

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While these organisms look very similar, they are actually very different. One is alive while the other is not.

  • Can you guess which one is considered living?

If you guessed the rod-shaped bacteria in the second photo, you guessed correctly!

  • Bacteria are alive, so what is the organism in the first image?

It is called a virus, and while it looks similar to bacteria, it is actually a very unique class of infectious agents.

  • So, how do we classify things as living or non-living?

There are characteristics that all living things possess. Let's take a deeper look at these characteristics of life.

  1. Take a sheet of paper and fold the two edges until they meet in the middle, appearing to be a French door.
  2. Then, cut each side twice so you get three flaps of equal size on each side.
  3. Label each of these with one of six characteristics:
Growth and Development Response to Stimuli
Cellular Organization Energy Use and Metabolism
Chemicals Necessary to Sustain Life Reproduction


Now that we have a format for capturing our learning, you will write down the definition of each characteristic, an example, and include a creative sketch!

View the What is Life? slideshow below to explore each aspect:

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Consider that just because a living organism meets these requirements doesn't mean it will survive in any environment.

  • Could a tropical plant survive in sub-Saharan Africa?
  • What about a human living in the deep sea?

Organisms were created for their environment and have specific needs based on their habitat.

As you watch a short video, Needs of Living Things, from Mark Drollinger, answer these questions:

  • What are the main needs of living things?
  • Why is water so important?
  • How are autotrophs and heterotrophs different?
  • How does living space influence living things?

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  • Did any of the needs surprise you?

Just think about how different autotrophs and heterotrophs are — imagine if humans could create food from sunlight!

Now that you have an understanding of the characteristics of life, let's move on to another learning activity in the Got It? section.

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