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384 BCE
Aristotle (Greek)
Aristotle believed in spontaneous generation (“abiogenesis”), but he did not conduct actual experiments to test this idea. He contributed to the cell theory with his basic classifications of living things.He classified different species and showed that there are connections between every organism. Which lead to the first principle of the cell theory. “All living things are made of cells and thus similar” -
Period: 384 to
The Cell Theory
A timeline showing when each scientist published their works and how they contributed to the development of the Cell Theory -
Robert Hooke (1635-1703)
Robert Hooke was an english scientist. He was first saw “empty boxes or empty rooms” in fossilized wood and named them "cells". Published book called Micrographia in 1665 which was a scinetific bestseller as it was the first book to illustrate insects, plants etc. as seen under microscopes. Contribution: He aided the creation of the cell theory by discovering the cell. -
Francesco Redi (1626-1697)
He was an Italian physician and the first person to test the abiogensis theory using experiments. Experiment: He placed meat into two different jars. One jar he covered with a cloth but let air in. The other jar he left open. He than discovered that the covered jar had no maggots. Contributions: He proved abiogenesis was fake. He also had a famous quote ""Omne vivum ex ovo" ("All life comes from an egg") which describes the third principle of the cell theory. -
Antony van Leeuwenhoek (1632-1723)
He became the first person to describe single-celled micro-organisms in 1674. With lenses that magnified up to 500x, he studied blood cells, pond-water organisms, and matter scraped from his teeth. After seeing them, he described them as “animalcules”. Contributions: Leeuwenhoek was considered the “father of microbiology’. He contributed by creating microscopes, which would help other scientists as they could now study the cells themselves in detail. -
Matthias Jakob Schleiden (1804-1881)
Schleiden was one of the founding fathers of cell theory along with Schwann. He concluded that “all plants are composed of cells and materials produced by cells”. Contributions: He contributed to the creation of the cell theory by creating it. Schleiden worked with Schwann to create the first version of the cell theory. -
Theodor Schwann (1810-1882)
Schwann studied animal tissues. Contributions:
- Summarized and organized his findings and the findings of other scientists over the centuries into the cell theory.
-Discovered that cells do not spontaneously appear which became the third principle of the cell theory.
-In 1839 Schwann published "Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants".
-In 1839 he also concluded that all tissues are made up of cells which became the first principle. -
Louis Pasteur (1822-1895)
French scientist who believed in biogenesis.
Experiment: Filled flasks with nutrient-rich broth and boiled them to get rid of air and microbes. As they cooled, air condensed near the neck. Pasteur predicted that air draw into the flask would contain micro-organisms, but wouldn't reach the broth. The broth remained clear, even with air.
Contributions: He disproved spontaneous generation thus proving the third principle of the cell theory. Disproved "active principle" via above experiment. -
Rudolf Virchow (1821-1902)
Rudolf Virchow was a German doctor pathologist and antrhopathologist. Virchow's experiments provided evidence for biogenesis and he made observations on the divison of cells. Contributions: He corrected Schwann and Schleiden's belief that cells formed from crystallization of budding and instead concluded that cells divided in order to produce more cells. “Where a cell exists, there must have been a pre-existing cell.” He used the cell theory to discover Pathology.
