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Aristotle and Spontaneous Generation
Aristotle was a firm believer in spontaneous generation, the belief that nonlivng things like mud could generate living tissue. Aristotle said that different animals generated based on what the material's elements and pneuma. For example, oysters grow in slime and flies generate on top of decaying vegetable or meat matter. This would eventually be proved wrong by Louis Pasteur's experiment.
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Invention of the Microscope
Zacharias Jansen invented the first microscope, which allowed people to see cells. Without it, the cell theory could never have been created.
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Van Helmont's Willow Tree Experiment
Biology ReferenceIn 1649, Jan Baptist van Helmont conducted an experiment in which he grew a willow tree sapling in 200 lbs. of soil. about 2 ounces of soil was lost when the tree was grow. He added only rainwater, so he believed that water could make wood. This supported Aristotle's belief in spontaneous generation. -
First Observation of Cells
Robert Hooke used a simple microscope to observe cork cells, drawings and sketches of which appeared in his book "Micrographia". This inspired Anton van Leeuwenhoek to make microscopic obervations of his own, which led to the discovery of single-celled organisms.
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Discovery of "Animacules"
Anton van Leeuwenhoek discovers the first live cells under a microscope. He observed bacteria and protozoa, which he named "animacules". This discovery was confirmed by Robert Hooke. This made many scientists want to take up the microscope and expand their visions in their experiments.
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Cell Theory Building Block
Lorenz Oken stated that all living things are made up of cells and are made from cells. This eventually helped lead to the first part of the cell theory being created, based on this statement.
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Robert Brown and Plant Cells
In 1831, Robert Brown, a botanist, had studied plants for a living. He published in a paper from his studies that plant cells had a cell wall and a nucleus, and that the nucleus had a lot to do with the making of the embryo. By doing this, he named the nucleus and also imlied that it was at the center of the cell.
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Plants are Composed of Cells
Matthias Schleidon discovers that plants are composed of living cells. This helped lead to Theodor Schwann creating the first part of the cell theory.How Stuff Works -
A Cell Theory Part
Theodor Schwann accepts Matthias Schieiden's idea that plants are composed of cells publishes "Microscopic Investigations on the Accordance in the Structure and Growth of Plants and Animals", which included the one of the parts of the Cell Theory: all living things are made of cells.
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A Cell Theory Part
Rudolf Virchow takes Schleiden and Schwann's findings and states that all living cells must rise from other living cells, another part of the cell theory. This was the beginning of the arguement against spontaneous generation, the idea that living tissue could generate from non-living things, that Louis Pasteur would carry on.
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Louis Pasteur's Experiment
How Stuff WorksLouis Pasteur conducts an experiment that rejects the idea of spontaneous generation. He got two flasks, and filled them with broth and boiled them, to kill any existing microbes. He cut the swan neck of one of the flasks, and let them sit there for some time. Germs got in the broth in flask #1, but could not go against gravity to get to the broth in flask #2. His outcome rejected the idea of sponteous generation. -
Part of the Cell Theory
Rudolph Albert von Kolliker publishes Entwicklungsgeschichte des Menschen und der höheren Thiere. In this book, he shows structure of the ear, eye, and brain. This book also shows that cells came from other cells, a part of the cell theory.
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