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Period: Sep 30, 1580 to
Evolution of The Cell Theory
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Zacharias Jansen
Zacharias Jansen invented the first compound microscope. A compound microscope has two or more lenses and a powerful magnification compared to a single lens microscope. Led to the discovery of cells because now they could be seen. -
Robert Hooke
Robert Hooke coined the term “cell.” Was the first person to see a cell although they were only the dead cells of plants. -
Marcello Malpighi
Italian microscopist Marcello Malpighi observed, for the first time, the blood capillaries present in fish tails. -
Anton Van Leeuwenhoek
Anton Van Leeuwenhoek improved magnification abilities by polishing lenses. He was the first person to observe living cells. Using a microscope, he was able to observe clearly and describe red blood cells and sperm cells in humans and other animals. -
Nehemiah Grew
Nehemiah Grew made detailed studies of plant cells and established the presence of cellular structures throughout the plant body. Grew suggested that the gas bubbles in rising bread may have formed through a similar process. Published “The Anatomy of plants” -
Matthias Schleiden
Matthias Schleiden concluded that all plant tissues are composed of cells and that an embryonic plant arose from a single cell. He declared that the cell is the basic building block of all plant matter. This was the first generalization concerning cells. -
**Theodor Schwann**
Theodor Schwann pulled existing observations together into a singular theory that stated: Cells are organisms and all organisms consist of one or more cells. The cell is the basic unit of structure for all organisms and that plants and animals consist of combinations of these organisms which are arranged in accordance with definite rules. In other words, the cell is the basic unit of life. Became known as the Cell Theory -
Rudolf Virchow
Virchow was the first to demonstrate that the cell theory applies to diseased tissue as well as to healthy tissue. Virchow was able to add a third tenet to the cell theory: all cells develop only from existing cells. -
Louis Pasteur
Pasteur contributed to the cell theory by disproving what was known at the time as spontaneous generation. This was the idea that living organisms can arise out of inanimate matter. He was the first scientist to prove that cells can only form from pre-existing cells. He did this by creating an experiment that showed cells would only grow in broth if air was exposed. -
August Weissmann
Based on Darwin's idea that specific inherited traits are passed from one generation to the next, Weissmann asserted that the genetic code for each organism was contained in its germ cells.The presence of genetic information in the germ cells explained it. In a series of essays about heredity published from 1889 to 1892, Weissmann also observed that the amount of genetic material did not double when cells replicated, suggesting that there was some form of biological control of the chromosomes.
