Origins: How Life Began

Student Handout

Life's Characteristics

Look around you and you can see life everywhere. There are many forms of multicellular life, such as insects, birds, dogs, cats, and humans. But there are also many single-celled organisms, such as bacteria and fungi, that are invisible to the naked eye. But what is this thing called life? What makes one thing alive and another one not? Look at the organisms in this illustration and see if you can identify the characteristics that show each organism is alive.