1. Cell Theory

2. Characteristics of Living Things
There are 5 characteristics of living things:
Living things respond to their environment
Living things need energy
Living things grow
Living things reproduce
Living things must get rid of waste
See page 10
(c) McGraw Hill Ryerson 2007

3. Discovery of Cells
The invention of the microscope let scientists discover cells.
Robert Hooke, a British scientist in the 17th century, created a microscope to observe tree bark. He called the structures “cells”.

4. Wacky History of the Cell video

5. Discovery of Cells
Other scientists observed single-celled organism living in pond water.
Their observations lead to “Cell Theory”

6. (c) McGraw Hill Ryerson 2007
Cell Theory
The cell is the basic unit of life.
See pages 31-32
(c) McGraw Hill Ryerson 2007

7. (c) McGraw Hill Ryerson 2007
Cell Theory
All cells come from other living cells.
(c) McGraw Hill Ryerson 2007

8. (c) McGraw Hill Ryerson 2007
Cell Theory
All organisms are composed of one or more cells.
See pages 31-32
(c) McGraw Hill Ryerson 2007

9. Check your understanding
Identify the statements that make up the cell theory. Give an example that supports each statement.
What processes of scientific inquiry do you think scientists used to establish the cell theory?

10. Is a Virus a Living Thing?
WB p11-13