They exist only in a narrow layer near the surface of the earth. This layer is called the biosphere because it is, as far as we know, the only place where life can exist. It includes the upper layers of the Earth's crust and the thin layer of soil that supports plant life. This zone of life extends about 8 km up into the atmosphere and as much as 8 km down into the depths of the seas. Living organisms are not distributed evenly throughout the biosphere.
Few organisms live on the polar ice caps and glaciers, and many live in the tropical rain forests.
Now that I have given you an overview of what we are studying today, I would like to divide you into groups. Each row will become a group. I will give each group one poster board, markers, magazines, scissors, glue. You will be asked to define your term and give examples of it. After you arrive at a definition of your term, draw or cut out pictures that will help the class remember your term.