Cell Theory The Scientists Cell Theory All life forms are made from one or more cells. Cells only arise from pre-existing cells. The cell is the smallest form of life. 1. Robert Hooke - 1665 Used a primitive microscope; only 30X magnification First described cells as ‘little boxes’ while looking at a piece of cork. Called a cell, a cell 2. Anton VanLeeuwenhoek 1675 Dutch microscope maker He studied his own cheek cells First scientist to study LIVING cells Leeuwenhoek=Living Cells are the smallest living thing. 1830’s 3. Theodor Schwann studied animals. He concluded that all animals are made of cells. 1830’s 4. Matthias Schleiden studied plants. He concluded that all plants are made of cells. 5. Rudolph Virchow - 1855 German pathologist (Studied Diseases) Demonstrated that cell theory applies to diseased tissue as well as healthy tissue He concluded that cells must come from pre-existing cells. Cell Theory Why do we need to update the cell theory? MODERN CELL THEORY INCLUDES Genetic information (DNA) is passed on from cell to cell. Endosymbiosis Endo = ???? Symbiosis = Relationship between two different organisms. Theory of Endosymbiosis 1. Eukaryotic cells came from Prokaryotic cells 2. Through symbiosis one original cell “ate” an energy making cell and a cell that makes its own food. 3. Evolving over time, the two cells combined to make ONE single organism.