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Jan 1, 1000
Aristotle
Approximately 335 BCE
Aristotle dissected and classified animals. He was trying to find the connection between the human body and soul. Some of his classyfications still exist today.
http://www.timetoast.com/timelines/cell-theory-timeline--20 -
Zacharias Jansen
Zacharias Jansen invented the first optical microscope.
http://ed.ted.com/lessons/the-wacky-history-of-cell-theory -
Jan Baptist van Helmont
Jan Baptist van Helmont believed n spontaneous generation, though his willow experiment, where he put a five pound willow plant in a pot with soil for five years giving it nothing but water grew to weigh 169 pounds, proved that cells grow from other cells. He believed the weight and plant growth came from water.
http://www.britannica.com/EBchecked/topic/260549/Jan-Baptista-van-Helmont -
Robert Hooke
Robert Hooke, through looking at a piece of cork, discovered and named cells. He later published the book Micrographia which describes his microscopic observations.
http://science.howstuffworks.com/innovation/scientific-experiments/scientific-method4.htm -
Anton van Leeuwenhoek
Anton van Leeuwenhoek learned to grind lenses together and assemble them into a simple microscope .He was the first person to observe bacteria and protozoa, he called them animolcules though. His observations layed the foundation for the sciences of both.
http://science.howstuffworks.com/innovation/scientific-experiments/scientific-method4.htm -
Lorenz Oken
Lorenz Oken created a new system of animal classification that demonstrated the path of evolution. He also believed that all organic beings originate from and consist of cells.
http://www.timetoast.com/timelines/cell-theory-timeline--20 -
Robert Brown
Robert Brown was the first person to recognize that the nucleus is essential for all living cells.
http://www.smithlifescience.com/celltheory.htm -
Theodore Schwann
Theodore Schwann observed that all parts animals are made of cells discovered the first statement of the cell theory along with Mattias Schleiden saying all living things are made of cells.
http://science.howstuffworks.com/innovation/scientific-experiments/scientific-method4.htm -
Mattias Schleiden
Mattias Schleiden observed that different parts of plants are made of cells. Also, he, along with Theodore Schwan made the first cell theory statement.
http://science.howstuffworks.com/innovation/scientific-experiments/scientific-method4.htm -
Albrecht von Roelliker
Albrecht von Roelliker realized that sperm and eggs are also cells.
http://www.smithlifescience.com/celltheory.htm -
Rudolph Virchow
Rudolph Virchow was the first person to recognize leukemia cells, and was one of the first people to accept the idea of cell division. His theory that all living cells come from preexisting cells became the third statement in the cell theory.
http://science.howstuffworks.com/innovation/scientific-experiments/scientific-method4.htm -
Louis Pasteur
Louis Pasreur disproved the popular belief of spontaneous generation using the swan-neck flask experiment. His experiments supported Rudolph Virchow's theory that all cells come from preexisting life which later became the third statement in the cell theory. -
Cell Theory Summarization
All living things are made up of cells.
Cells make up every part of an organism.
Cells can only come from the reproduction of other existing cells.
