Cell Theory Time

Aristotle

330 BCE

Aristotle discovered the theory called epigenesis. He made this discovery around 330B.C. This helped disprove spontaneous generation by proving that cells differentiate or change as organisms grow.

Zacharias Jansen

1590

Invented the compound optical microscope.
Jansen invented the compound optical microscope in 1590.
It helped the rejection of spontaneous generation by observing that things you can not see still exist.

Jan Baptist van Helmont

1620

Helmont partially discovered the process of photosynthesis. He made this discovery in 1620. Even though he agreed with spontaneous generation he helped disprove it by saying that plants get their energy from water and different gases.

Robert Hooke

1665

Observed a cork and discovered cells on the cork. In 1665, Hooke discovered the cells on the cork. It helped the rejection of spontaneous generation by understanding that cells are the smallest unit of life.

Anton van Leeuwenhoek

1674

Discovered single celled organisms. Leeuwenhoek found these single celled organisms in 1674. It helped the rejection of spontaneous generation by proving there are organisms that exist even if you can't see them.

Lorenz Oken

1805

Oken stated that, "All living organisms originate from and consists of cells." He made this statement in 1805. This helps disprove spontaneous generation by saying that living organisms are made out of cells, and not just nothing.

Robert Brown

1831

Brown discovered the nucleus and its role inside a cell. He made this discovery in 1831. He helped disprove spontaneous generation by proving that cells are made from pre-existing cells.

Matthias Schleiden

1838

Schleiden found that cells are the basic unit of plants and animals. He made this discovery in 1838. Schleiden helped disprove spontaneous generation by saying that cells are the basic unit of life.

Theodor Schwann

1839

Discovered that all tissues were made out of cells. Schwann discovered cells in tissue in 1839. It helped rejection of spontaneous generation by proving cells made up parts of living things.

Albrecht von Roelliker

1840

Roelliker discovered that the sperm and egg are composed of cells. He made this discovery in 1840. This helped disprove spontaneous generation by explaining that life is made from cells from beginning to end.

Rudolf Virchow

1855

Found that cells are made out of pre-existing cells and diseases occur at the cellular level. Virchow made this discovery in 1855. It helped rejection of spontaneous generation by stating that cells are made of cells and diseases happen do to cells not randomness.

Louis Pasteur

1859

Pasteur proved that cells can only form from pre-existing cells with a broth experiment. Pasteur made this discovery in 1859. It helped reject spontaneous generation by showing how bacteria grew on broth once it came in contact with air.