Lesson 1 of 8

Lesson 1: The Characteristics of Life and the Scientific Method

Biology is the study of living things. Before you can study life, you have to be able to tell what is alive. Scientists agree on a short list of traits that every living thing shares.

  • Made of one or more cells
  • Uses energy and has a metabolism
  • Grows and develops
  • Reproduces (makes more of its kind)
  • Responds to its environment (stimuli)
  • Maintains homeostasis (a stable inside)
  • Has DNA and can evolve as a group over time

KEY TERM

Homeostasis is how an organism keeps its inside conditions steady, like your body holding a temperature near 98.6 degrees Fahrenheit even when it is hot out.

The Scientific Method

This is the step-by-step way scientists answer questions. Learn the order.

  1. 1Observe and ask a question
  2. 2Form a hypothesis (a testable, if-then prediction)
  3. 3Design and run an experiment
  4. 4Collect and analyze data
  5. 5Draw a conclusion and share results

ON THE TEST

In an experiment, the independent variable is what you change, the dependent variable is what you measure, and the control group is the untreated group you compare against. Change only one variable at a time.