History of Cell Theory

The First Description of The Cell

1665

Robert Hooke lived from 1635-1702.
This event is important because in 1665, Robert Hooke looked at a thin slice of cork under a microscope and saw a honeycomb structure made up of small compartments he called cells.
I chose this event for my timeline because the first description of the cell is generally attributed to Robert Hooke, an English physicist who was also a distinguished microscopist.

Microorganisms

1676

Leeuwenhoek lived from 1632-1723.
This event is important because Leeuwenhoek was the first person to see living cells under a microscope.
I chose this event because Leeuwenhoek significantly improved the quality of microscope lenses. He could see the single celled organisms that lived in a drop of pond water (“animalcules"). The particles that he saw under his microscope motility equates to life. He concluded in a letter to the Royal Society, that particles were living organisms.

Nucleus

1831

Robert Brown lived from 1773-1858.
This event is important because in 1831, Robert Brown was the first person to discover the nucleus in plant cells.
I chose this event for my timeline because Brown introduced the term "nucleus." His discovery of the nucleus and its role helped to put together the cell theory, which states that all living organisms are composed of cells, and cells come from pre-existing cells. Brown's discovery helped to confirm the second half of the cell theory.

The First Foundational Belief About Cells

1838

Matthias Schleiden lived from 1804-1881.
This event is important because it suggested that every structural element of plants is composed of cells or their products.
I chose this event for my timeline because Matthias Schleiden proposed the first foundational belief about cells, that all plant tissues are composed of cells. He declared that the cell is the basic building block of all plant matter. This statement of Schleiden was the first generalizations concerning cells.

Formation of Cells

1839

Theodor Schwann lived from 1810-1882.
This event is important because Theodore Schwann stated that “the elementary parts of all tissues are formed of cells” and that there is one universal principle of development for the elementary parts of organisms... and this principle is in the formation of cells .
I chose this event for this timeline because Theodor Schwann concluded that all animal tissues were made of cells.

Cells Are Products of Other Cells

1850

Louis Pasteur lived from 1822-1895.
This event is important because Louis Pasteur contributed to the cell theory by supporting the idea that cells are products of other cells in 1850.
I chose this event for my timeline because Louis Pasteur created an experiment that showed cells could only be formed from pre-existing cells. His discovery helped lead to the rejection of the theory of spontaneous generation by proving that living things are products of cells, which are living things.

Cell Division

1852

Robert Remak lived from 1815-1865.
This event is important because the theory of cell division plays an important role in all living organisms, as it is essential for growth, repair and reproduction.
I chose this event for my timeline because Robert Remak discovered that cells come from previous cells through cell division of preexisting cells. He published convincing evidence that cells are derived from other cells as a result of cell division.

Omnis cellula e cellula

1855

Rudolf Virchow lived from 1821-1902.
This even is important because Virchow’s aphorism Omnis cellula e cellula (every cell from a pre-existing cell) became the basis of the theory of tissue formation, even if the mechanisms of nuclear division that were not understood at the time.
I chose this event for my timeline because the third part of the original cell theory was put forth in 1855 by Rudolf Virchow.

Direct Fusion

1867

Albert Kölliker lived from 1817-1905.
This event is important because Albert Kölliker advocated that tissue should be studied and understood as a mass of individual cells.
I chose this event for my timeline because in the fifth edition of Kölliker's important book on histology, published in 1867, he proposed that sensory and motor cells of the right and left halves of the spinal cord were linked “by anastomoses” (direct fusion).

Mitosis

1882

Walther Flemming lived from 1843-1905.
This event is important because Walther Flemming described chromosome behavior during mitosis.
I chose this event for my timeline because Walther Flemming analyzed structures and processes in the cell nucleus under a microscope. He was the first person to conduct a systematic study of chromosomes during division and called this process mitosis. Flemming introduced the term ‘‘mitosis’’ in 1882 and gave a superb description of its various processes.