Cell Theory Timeline

Cell Theory Timeline

Period: Jan 1, 1500 to Jan 1, 1900

The three main principles in the Cell Theory:
- all organisms are composed of one or more cells
- cells are the smallest unit of life
- all cells came from pre-existing cells

Hans and Zacharias Janssen: invented the first compound microscope

Oct 11, 1595

Robert Hooke: discovered the cellular composition of cork

Jan 1, 1665

First described cells while observing cork with a microscope he built himself.

Anton van Leeuwenhoek: "animacules" were discovered

Jan 1, 1676

"animalcules"= living cells ("little animals")

Anton van Leeuwenhoek: discovered bacteria

Oct 11, 1683

discovered bacteria by using a sample of saliva from his mouth

Robert Brown: discovered the nucleus of cells

Jan 1, 1831

He stresses its importance in fertilization.

Matthias Schleiden: stated that plants are made up of cells

Jan 1, 1838

He called the cells "independent, separate beings"

Theodor Schwann: stated that animals are made up of cells

Jan 1, 1839

Wilhelm Hofmeister: mitosis in plants

Jan 1, 1849

Rudolph Virchow: stated that all living things come from other living things

Jan 1, 1855

Louis Pasteur: proved that all cells come from pre-existing cells using sterilized chicken broth

Jan 1, 1860

After sterilizing chicken broth by boiling, he showed that living organisms would not "spontaneously" reappear. Only after exposure to pre-existing cells was life able to re-establish itself in the sterilized chicken broth.

Ernst Ruska: constructed the first electron microscope

Mar 9, 1931