The Wacky History of Cell Theory

When you hear the word “scientist,” what do you think of? A person in a white coat working in a laboratory? It’s true that many scientists do important work this way. But scientific theories don’t usually come from a single person working in a lab. They often come from several different scientists building on each other’s discoveries.

Case in point: Cell Theory. This theory is one of the foundations of biology. Cell theory has three parts:

1. All organisms (living things) are made up of one or more cells.

2. The cell is the basic unit of structure and organization in organisms.

3. All cells come from preexisting cells.

It took a few steps and a few scientists to come up with this theory.

Part One: The Microscope

The story of cell theory started in the Netherlands in the 1600s. There, a spectacle-maker named Zacharais Janssen is said to have invented a compound microscope. A compound microscope uses two lenses. One lens is close to the object being viewed. This is called the objective lens. The other lens is close to the viewer. This is called the eyepiece. Microscopes became extremely popular among scientists.

Did you know?

Many people believe Zacharais Janssen invented the first microscope and telescope. But this has never really been proven. There were many other scientists working on similar inventions at the time.

Part Two: The Discovery of Bacteria

Another Dutch scientist, Antoine van Leeuwenhoek, decided to make his own microscope. He began looking at all kinds of matter with his invention. He even looked at the scrapings off his own teeth. That’s how he discovered bacteria!

Did you know?

Van Leeuwenhoek thought bacteria looked like little animals. So he called them animacules. 

Part Three: The Discovery of Cells

Van Leeuwenhoek wrote letters to a scientist friend in England named Robert Hooke. Hooke also studied objects with a microscope. He studied a piece of cork and noticed it was divided up into little chambers. These reminded him of monastery cells. So, he named his discovery cells.

Parts Four & Five: More discoveries about cells

Next came the work of two German scientists. Matthias Schleidan was a botanist. He used microscopes to study plants. Eventually, he realized that all the plants he looked at were made of cells. 

Meanwhile, Theodor Schwann studied slides of animal cells. He concluded that all animals were also made of cells!

Part Six: Preexisting Cells

Eventually, Schneidan and Schwann joined forces and started to develop the cell theory. But they disagreed on the third point: that all cells come from preexisting cells. It took a third scientist, Rudolf Virchow, to prove that cells did indeed come from other cells. But the research he used to prove this actually came from a German Jewish scientist named Robert Remak!

What can we learn from the history of cell theory?

So, what does this story tell us? Two things. First, scientific theories often involve building off of other people’s discoveries. Second, you never know where a scientific theory might come from. It could be sitting in the guck on your teeth!