Cell Theory Timeline Famous Scientists Scientist Han & Zacharias Janssen Robert Hooke Anton van Leeuwenhoek Matthias Schleiden Theodor Schwann Year 1595 Discovery They made the first microscope by placing 2 lenses in a tube. 1665 He studied many objects in his primitive compound microscope and published a book of it. 1680 He described cells in a drop of pond water using a simple microscope with only one extremely good lens to look on the blood, insects, and many more. He was describing about the cells and bacteria. He made his own fine quality lens for use in monocular microscope. 1838 He was stating that the cell is the basic building block of all plants matter because the tissues are composed of cells. An embryonic plant arose from a single cell. 1839 He was stating that the animal and plant cells have different structures. The tissues are made of cells. Rudolph Virchow 1855 He was demonstrating the diseases of tissues. All these events led to the realization of the cell theory. The Cell Theory 1. All living organisms are composed of cells. They may be unicellular or multicellular. 2. The cell is the basic unit of life. 3. Cells arise from pre – existing cells. Questions: 1. What theory did these scientists provide evidence for? It is the cell theory. 2. What instrument was necessary before the cell theory could be developed? The microscope. 3. Which three scientists directly contributed, evidence for the cell story? The 3 scientists that contributed for the cell theory are Mathias Schleiden, Theodor Schwann, and Rudolph Virchow. 4. How did the earlier scientists and their contributions directly affect the discoveries of later scientists? For example, what had to come first? Hans and Zacharias Janssen had to first develop the microscope before cells could be discovered. Robert Hooke then discovered empty, dead cork cells in tree bark. Anton van Leeuwenhoek discovered the existence of living cells and is sometimes given credit for the microscope. Resources: Media, Nobel. "Microscope: Time Line." Www.nobelprice.org. 26 Feb. 2012 http://www.nobelprize.org/educational/physics/microscopes/timeline/ "Discovery of Cells and the Development of Cell Theory." Www.smithlifescience.com. 26 Feb. 2012 http://www.smithlifescience.com/celltheory.htm About.com. "Cell Theory." Www.biology.about.com. 26 Feb. 2012 http://biology.about.com/od/biologydictionary/g/celltheory.htm Department of Science. "Staying Alive: Teachers Support Material." Www.xtec.es. 26 Feb. 2012 http://www.xtec.es/sgfp/llicencies/200506/memories/1098/1098a2.pdf http://www.xtec.es/sgfp/llicencies/200506/memories/1098/1098a2.pdf http://www.xtec.es/sgfp/llicencies/200506/memories/1098/1098a2.pdf Hans and Zacharias Janssen. Www.unitten.org. 26 Feb. 2012 http://www.unitten.org/CMS/web_site/07-­‐
08_Photo_Album/Baer/2nd%20Hour%20Webpages/Stehman%20and%20Bickel-­‐
Microscopes/Microscope%20Webpage.html Robert Hooke. Www.realmagick.com. 26 Feb. 2012 http://www.realmagick.com/robert-­‐
hooke/ Rudolph Virchow. Www.askthebrain.com. 26 Feb. 2012
http://www.askthebrain.com/rudolph_virchow-.html