1. Cell Theory Timeline

2. Cell Theory 1. All living things are made of cells. 2. Cells are the basic units of life. 3. Living cells only come from other living cells.

3. Aristotle 334 B.C.E. Aristotle observed nature directly. He classified all known organisms as either plants or animals. B.C.E.= Before Common Era

4. It all started with… The first microscope! – Zacharias and Hans Jansen – 1595 – Middleburg, Holland – Placed two lenses in a tube

5. Hans & Zacharias Janssen 1595 Hans & Zacharias Janssen produced the first compound microscope by lining up 2 lenses.

6. Robert Hooke 1665 Robert Hooke observed lining matter (cork cells) through a compound microscope, which reveals empty cells. He is the first to call the spaces in the cork “cells” which means little rooms.

7. Anton van Leeuwenhoek 1675 Anton van Leeuwenhoek observed living bacteria and blood cells through a simple microscope.

8. Matthias Schleiden 1838 Matthias Schleiden discovered that plants were made of cells. He believed plant growth happened through the production of new cells

9. Theodor Schwann 1839 Theodor Schwann states “all animals are made of cells.” Believed plant and animal cells were different in structure, but the cell was the basic unit for life.

10. William Henry Perkin 1856 William Henry Perkin develops an intense purple dye, which is used to stain slides.

11. Rudolph Virchow 1858 Rudolph Virchow states… – “Cells are the last link in a great chain that forms tissues, organs, systems, and individuals. Where a cell exists, there must have been a preexisting cell.” Cells can only arise from pre-existing cells He also stated that diseases caused changes in a normal cell