The Cell Theory Timeline

1. The Cell Theory Timeline

2. Hans and Zacharias Janssen were the first to invent the compound microscope (2 lenses). to be dated in the 1590s. The father and son team worked together as spectacle makers in Middleburg, Holland. Hans and Zacharias Janssen

3. Robert Hooke (1635-1703) Robert Hooke was the first person to describe cells. In 1665, he built a microscope to look at tiny objects. When he looked at a piece of cork which is found in the bark of cork trees, the cork looked like it was made of little boxes. Hooke named these boxes cells, which means “little rooms” in Latin. Hooke’s cells were really the outer layers of dead cork cells.

4. Anton van Leeuwenhoek (1632-1723) Anton van Leeuwenhoek was a Dutch merchant who made his own microscopes. In 1674, Leeuwenhoek looked at pond scum under one of his microscopes and saw small organisms in the water that he named animalcules, which means “little animals”. Today we call these single-celled organisms protists. Leeuwenhoek also looked at blood cells and was the first person to see bacteria.

5. Matthias Schleiden (1804-1881) In 1838, Matthias Schleiden concluded that all plant parts were made of cells.

6. Theodor Schwann (1810-1882) Theodor Schwann studied animals. In 1839, he concluded that all animal tissues were made of cells.

7. Rudolf Virchow (1821-1902) In 1857, Rudolf Virchow, a doctor, saw that cells formed only from other cells.

8. The observations of these three German scientists, Matthias Schleiden, Theodor Schwann, and Rudolf Virchow, together form the cell theory. • The Cell Theory • All organisms are made of one or more cells. • The cell is the basic unit of all living things. • All cells come from existing cells.

9. Timeline source: http://www.biology.arizona.edu/cell_bio/tutorials/cells/cells3.html Holt Science and Technology textbook Chapter 7: Cells: The Basic Units of Living Things.