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Janssen Invents the Microscope
Zacharias Janssen and his partner begin expiriments by putting several lenses in a tube and finding that the object at the end of the tube was greatly enlarged. This invention allowed following scientists to site and observe cells. -
Robert Hooke Discovers Cells
While observing a piece of cork Hooke saw many boxes reesmbling rooms. Therefore he was the first to observe cells which led to a greater understanding of cells and life and to the first part of the cell theory. -
Leeuwenhoek Observes Animalcules
Dutch scientist Anton van Leeuwenhoek viewed water from a pond and discovered creatures inside in which he gave the name animacules (now known as single celled organisms). Also contributed to the progression of a more powerful microscope and was the first to observe muscle fibers and bacteria. -
Lorenz Oken
Oken stated that "All living organisms origniate and consist of cells". Also developed a new system of animal classification based on evolution. He elieved in both ideas that all living organisms have cells and that cells are formed by preexisting cells. -
Robert Brown Observes Plant Cells
Brown first observed plant cells and then discovered and named the cell nucleus. He believed that all living things are composed of cells. -
Matthias Schleiden
Schleoden observed plants on a microscopic level and concluded all plant tissues are composed of cells. He declared that the cell is the basic building block of plant matter. -
Animals are Made Of Cells
Theodor Shwann concludes that animals as well as any other living things are composed of cells. Also discovered the digestive enzyme pepsin and observed the formation of yeast spores and concluded the fermentation of sugar and starch was a biological process. Shwann was a founder of the cell theory by not only leading our knowledge in cells further, but also questioning spontanious generation. -
Albrecht von Roelliker
Albrecht von Roelliker fianlly realized that sperm and egg cells were cells as well. -
Virchow Strengthens the Theory
Rudolph Virchow was the first to demonstrate that the cell theory applies to both normal and diseased cells. This strengthened the theory that cells exist from preexisting cells. -
Pasteur Ends Spontanious Generation
Conducted an expiriment, which allowed air to contact a broth. Microbes present could not make it around the bends of the flask preventing them from entering the broth. This ended any remaining ideas of spontanious generation and is now know as Pasteurization. -
Aristotle
Aristotle was the first to theorize that each germ must have come from another and introduced the ideaa that each gene has a definite parent and a similar offspring.
