Timeline: Development of Cell Theory

300

Spontaneous Generation

Aristotle
Aristotle said that there was no difference between living and nonliving things. This started the idea of spontaneous generation.

Nov 6, 1595

First Microscope Invented

Link to Jansen
Jansen invented the first compound microscope which allowed people to see cells.

Jan 1, 1600

Mice Recipe

[Jan Baptista van Helmont](www.britinnica.com/EBcheck/topic/101517/cell-theory)Around 1600, Jan Baptista van Helmont came up with the recipe for rice which was dirty clothes+wheat+21 days=mice. This added to the idea of Spontaneous Generation.

Jan 1, 1665

Cells Found

Robert Hooke
In 1665, Robert was the first to observe cells by looking at a piece of cork through a microscope. He also gave cells their name.

Jan 1, 1670

Bacteria and Protozoa

Anton van Leeuwenhoek
Around 1670, Leeuwenhoek observed bacteria and protozans. It showed that there are microorganisms.

Jan 1, 1800

All Livng Things Are Made of Cells

[Lorenz Oken](www.britinnica.com/EBcheck/topic/101517/cell-theory)
Around 1800, Oken suggested that all living things are made of cells.

Jan 1, 1831

Nuclei

Robert Brown
Robert Brown discovered nuclei in both animal and plant cells.

Jan 1, 1838

Parts of Plants Made of Cells

Mathias Schleiden
Mathias found that parts of plants were made of cells. He was one of the founders of the Cell Theory.

Jan 1, 1839

Plants Are Made of Cells

Theodor SchwannIn 1839, Theodor Schwann recognized nuclear structures in animal cells that he had also seen in plant cells earlier. He then added to cell theory that all plkants are made of cells.