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The Development of Cell Theory

Cell theory is a basic principle of modern biology. It is an important foundation for many other concepts in biology. Many scientific advancements led to the development of cell theory.
A microscope image of cells.

Three Principles of Cell Theory 

Cell theory has three main principles:
  • They are the most basic unit of life. 
  • All new cells come from other cells. 
These principles help scientist better understand living things. Understanding cells is important for scientific research. Scientists can create new medicines based on their knowledge of cells. Cell theory also helps scientists learn more about plants and animals.

Spontaneous Generation

Before cell theory, there was a theory called spontaneous generation. It stated that living things can come from non-living materials. For example, they thought that fleas could come from dust. Now we know this is not true! Fleas can only come from other fleas. 
The Greek philosopher Aristotle developed the idea of spontaneous generation. It was not disproved until the mid-1800s! We now know that living things can only come from other living things. Cells create new cells through two processes called meiosis and mitosis. 

A microscope image of cells dividing.

Mitosis is one way that cells create new cells.

Hooke, Leeuwenhoek, and the Cell  

The development of cell theory began with the discovery of the cell in 1665 by Robert Hooke. Hooke was a scientist from England. He used microscopes to see dead cells in a piece of cork. He was the first person to come up with the idea of a cell. 
Another scientist, Anton Van Leeuwenhoek, also used microscopes to study cells. In 1674, he was the first person to see living cells under a microscope. He looked at cells inside of algae. 

An image of a scientist working with a microscope.

Scientists like Hooke and Leeuwenhoek used microscopes to discover cells. Today, scientists still use microscopes to make scientific discoveries.

Schwann and Schleiden

German scientists Matthias Schleiden and Theodor Schwann developed cell theory in the 1800s. Schleiden was a botanist and Schwann was a physiologist. Schleiden studied plants and Schwann studied animals. Together, they realized that all living things have cells and that cells are the basic unit of life. These are the first two principles of cell theory. 
Another important scientist for the development of cell theory was Rudolph Virchow. Although he did not come up with the basic ideas for cell theory, he added on to them. He used the phrase “omne vive ex ovo,” which means that every living thing comes from other living things.
Also, because all living things are made out of cells, all cells come from other cells. This is the third principle of cell theory.

Modern Cell Theory

Today, scientists have added new concepts to the original three principles. These new principles include:
  • Cells pass information (DNA) to new cells when they divide.
  • Energy flows inside of cells. 
  • All cells are made out of the same chemicals. 
These concepts might seem advanced, but that’s because we know a lot about cells now. Every day scientists learn more about cells! Cell biology is an important field of science that helps us learn more about living things. 

An image of scientists working in a lab.

Scientists know more about cells now than ever before!

Watch this fun video about the history of cell theory: 

Other Great Resources

Cell Biology Timeline: https://bitesizebio.com/166/history-of-cell-biology/

Kiddle Encyclopedia Entry: https://kids.kiddle.co/Cell_theory

Living Things are Made of Cells: http://www.biology4kids.com/files/cell_main.html

Written By: Leah Tolby