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1500 BCE
Ancient Egyptians
Egyptians had minor knowledge of human anatomy, as priests who prepared corpses for burial learned and gained experience about the knowledge of human anatomy as they removed the vital organs in the body. This will lead on to aid in the knowledge of how the vital organs work and ponder about the many small systems which make them work, know known as tissue, or a group of cells specialized for a specific function in an organ. -
329 BCE
Aristotle
Aristotle is known as the best student of biology in the ancient world. He is known as the one who initiated the cell theory as he was the first person to try and define what made a living thing. This led on to discover that a cell is the most basic unit of structure and function in a living organism as scientists tried to search for the main thing which made up all living things. -
500
Medieval Eurpoeans
The middle ages were of the first people to come up with the hypothesis of spontaneous generation. They did this by burying a pork leg, waiting one week, then finding insects in it after returning. This new claim was vital for people of the time, as they needed to know whether living things grow spontaneously or come from something, leading to further more advanced studies leading to proving it wrong with the cell theory finally claiming that "All cells come from pre-existing cells". -
Dec 31, 1514
Andreas Vesalius
Andreas gave the first accurate and complete description of the human body. He is one of the first scientists in history to fully dissect and classify each part of the human body. This helped lead to understand how organisms are made of different small systems, making up a living thing, which meant to further research that these small systems also needed to have smaller things making them up, leading to postulate one. -
Hans and Zacharias Janssen
Zacharias and his son, Hans were known for inventing the compound optical microscope. They produced the first compound microscope by combining two convex lenses with a tube. This contributed to cell theory by making it easier to view and examine cells and small structures. -
Robert Hooke
Robert Hooke viewed a thin cutting cork, and discovered empty spaces inside, and called them pores or cells. He calculated the number of cells in a cubic inch to be 1,259,712,000. He was the first person to use the term "cell" when describing biological organisms. He studied plants and came up with the idea of cells, which is the largest contribution to Cell Theory as cells may not have been discovered for 100's of years later. -
Francesco Redi
Redi was the first scientist who attempted to challenge the theory of spontaneous generation. He demonstrated that maggots come from eggs and flies, and later published his experiments on "The generation of insects", which helped to disproving the theory of spontaneous generation and coming up with postulate three, stating that all cells come from pre-existing cells. Without his findings, the cell theory would not be complete. -
Period: to
Anton Van Leeuwenhoek
Known as the "Father of Microbiology", Anton first discovered single-celled organisms, which he called "animalcules" while observing pond water. He was one of the first people to observe prokaryotes by discovering bacteria from a sample of his saliva. This contributed to the cell theory by discovering organisms with one cell, which helped prove that a cell is really the most basic unit of life. -
John Needham
John Needham conducted an experiment which proved abiogenesis, which is the idea that life occurs spontaneously at the microscopic level without the need of reproduction from pre-existing life. However, he did believe that a cell was the basic building block of all living matter. Although he opposed the theory that all cells come from pre-existing cells, his claim encouraged Lazzaro Spalanzi to disprove it later on, meaning he indirectly contributed to the theory. -
Lazzaro Spallanzani
Spallanzani's research on Biogenesis paved the way for the downfall of spontaneous generation. He found out that as long as a material was hermetically sealed, microbes did not re-appear. Needham argued that the experiments which Lazzaro conducted destroyed the "vegetative force" required for spontaneous generation to occur, however this was later fully disproven by Pasteur. This helped contribute to research on how cells do come from already pre-existing cells and do not appear spontaneously. -
Jean-Baptiste Lamarck
Jean stated that "no body can have life if its constituent parts are not cellular tissue or are not formed by cellular tissue. His work and contribution on cell theory would later help prove the three postulates of cell theory, seeing that a cell is the basic unit which builds tissue and in return with more than one cell, help build organ systems in living things. -
Lorenz Oken
Lorenz Oken made four statements that together made up cell theory:
1. All Living things are made up of cells
2. Cells are alike in structure and function
3. Cells need information in order to survive
4. New cells come from old cells Oken's statements are a massive contribution to cell theory as they are very similar in meaning and helped in formulating the three postulates of cell theory as we know it today. -
Robert Brown
Robert Brown was a Scottish Botanist. He discovered the nucleus in cells while looking at plant cells, which was a contribution as it showed that all living things were made of one or more cells -
Theodor Schwann
Schwann stated that all animal tissues are made of cells, and wrote the first two postulates of cell theory. He also discovered Schwann cells in the peripheral nervous system, and suggested that fermentation was indeed a biological process. His contribution to cell theory is very clear and significant as he is the one who wrote that "A cell is the most basic unit of structure and function in living things" and "All organisms are made up of one or more cells". -
Matthias Schleiden
Matthias discovered that plants were also made up of cells along with humans. Which helped prove that a cell is the basic unit of life in all living things. He then created what is called cell theory stating that all living things as made up of one or more cells. -
Rudolph Virchow
Virchow published omnis cellula e cellula (every cell stems from another cell). He also demonstrated and proved that cell theory applies also to diseased tissue as well as healthy, strengthening the theory. He suggested that all cells come from pre-existing cells and stated that not all plants are made up of cells, eventually leading to the formulation of cell theory. -
Louis Pasteur
Pasteur contributed to cell theory by completely and finally disproving the theory of spontaneous generation. He was the first scientist to legitimately prove that cells can only come from pre-existing cells. He did this by creating an experiment showing cells would only grow in a pot of broth only if air was exposed. His experiments showed that microorganisms come only from other microorganisms and that genuinely sterile solution remains lifeless identify unless contaminated by living creatures