The Evolution of The Cell Theory

In 1595 Zacharias Jansenn invented the compound microscope.

I. This scientist indirectly contributed to the cell theory. By creating the microscope that allowed Robert Hooke to discover the first cells, Jansenn gave him the tool he needed to make an innovative discovery,
II. Zacharias Janssen made this contribution in 1595
III. Janssen's invention didn't necessarily debunk spontaneous generation, but it did allow for other people to use it as a way to collect more information regarding cells. With the newfound information, future scientists could finally debunk the theory of spontaneous generation.

In 1665, Robert Hooke made the revolutionary discovery of the cell. Through the use of a microscope, Hooke was able to see what he believed was a plant cell, though, in actuality, Hooke was looking at dead cell walls that belonged to a piece of cork. At the time, Hooke was unaware of the fact but it did not stop him from naming his observation "cell". He called it this because he noticed the cork had tiny, room-like indentations which reminded him of cellulas or small rooms monks lived in.

I. Hooke contributed to the cell theory by literally discovering cells.
II. Hooke made this contribution to the cell theory in 1665.
III. Hooke's discovery help paved the way to the rejection of spontaneous rejection by demolishing the idea that living things came out of nothing or nonliving things. In truth, while Hooke only saw dead cell remains, it still proved that there was something that made up a once-living thing

The year 1673 rolled around and another scientist made an enormous contribution to the cell theory. Anton Van Leeuwoken crafted specific lenses for a microscope he used to observed microorganism from a lake as well as the stinger of bees. Additionally, around 1720 Leeuwoken also was credited with discovering a type of bacteria, that of which is called protists.

I. This scientist contributed to the cell theory by being the first to prove that a living thing has cells. Hooke could not take credit for this as he only witnessed the dead cells in a piece of cork.
II. This scientist made his contribution to the cell theory in 1673.
III. This scientist's discovery helped lead to the rejection of spontaneous generation through supporting the notion that living things must come from somewhere and must be made out of some "entity" instead of randomly appearing out of thin air or abiotic factors.

By 1838 scientist Matthias Jacob Schleiden continued to analyze plants and their cells through a compound microscope. Through various analysis, he noticed that cells were a consistent attribute all plants had. He proposed that cells were a fundamental unit of life and that all living things have them.

I. This scientist contributed to the cell theory by creating one of the most prominent characteristics of the cell theory, that of which is "cells are the fundamental units of life"
II. This scientist made the discovery in 1838
III, This discovery helped debunk the theory of spontaneous generation by supplying the public with the fact that all in order for something to be alive, it has to be made up of cells.

In 1839, just a year after Matthias Schleiden's revolutionary input on the cell theory, Theodore Schwann became interested in Schleiden's research. Matthias Schleiden's research primarily targeted plants and revealed that plants did indeed have cells. However, Schwann was curious as to whether this would be the case with animals. Schwann went on to analyze animal tissue and thus, the fact that all living things have cells was permanently ingrained into the cell theory.

I. This contributed to the cell theory as it officially confirmed the fact that all living things contain cells of some kind, be it plant or animal.
II. Theodore Schwann made the contribution in 1839.
III. This discovery helped reject the theory of spontaneous generation by encouraging that living things don't appear out of non- living things.

Louis Pasteur created an experiment that showed cells could only be formed from pre-existing cells.

I. This scientist contributed to the cell theory by supporting the idea that cells are products of other cells.
II. Louis Pasteur made this contribution in 1850.
III. This scientist's 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.

Virchow completed the third statement prominent in the Cell Theory. Through extensions research, Virchow supported the claim that all cells arise from other cells. Virchow also stated that diseased cells can be a product of healthy ones.

I. Rudolph Virchow contributed to the cell theory by proving the third statement to be true; cells come from other cells.
II. It was around 1855 when Rudolph Virchow made this contribution.
III. This scientist's contribution dispelled the theory of spontaneous generation by proving that living things do not come from nothing. All living things, which are made of cells, come from other living things.

https://bitesizebio.com/166/history-of-cell-biology/
http://www.the-scientist.com/?articles.view/articleNo/36699/title/Sketching-out-Cell-Theory--circa-1837/
http://www.ucmp.berkeley.edu/history/leeuwenhoek.html
https://www.saylor.org/site/wp-content/uploads/2010/11/Wiki-Cell-Theory.pdf
http://www.bookrags.com/biography/matthias-jacob-schleiden-wsd/#gsc.tab=0
http://www.encyclopedia.com/people/science-and-technology/cell-biology-biographies/theodor-schwann
https://www.famousscientists.org/rudolf-virchow/