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Cell Theory Timeline by David Robins

  • Hooke's Contribution

    Hooke's Contribution
    The first contribution made to the cell theory was by a scientist named Robert Hooke. In 1665, Hooke was the first to discover cells. Hooke made this discovery by cutting thin slices of a cork and examining them under a microscope. Hooke found that inside this cork contained a multitude of tiny pores that reminded him of the walls of a honeycomb. Hooke called these pores cells and published his findings in Micrographia, the first book to illustrate plants, insects, and more through a microscope.
  • Hooke's Model

    Hooke's Model
    Hooke's model improved upon the ones before it as it was the first to state from observations that living things were made of cells.
  • Leeuwenhoek's Contribution

    Leeuwenhoek's Contribution
    The second contribution to the cell theory was made by a dutch biologist named Anton van Leeuwenhoek. Leeuwenhoek is best known for his developments to the microscope. Leeuwenhoek handcrafted a single-lens microscope that would give him magnifications up to 270x. In 1674, Leeuwenhoek observed pond water and found microscopic beings which he described as "amimalcules". In his writings he described the algae, Spyrogyra, along with other protists. He also scraped his tooth to examine bacteria.
  • Leeuwenhoek's Model

    Leeuwenhoek's Model
    Leeuwenhoek's model improved upon the previous model as he made a more powerful microscope and discovered that there were also living cells that we could not see without a microscope.
  • Brown's Contribution

    Brown's Contribution
    The third contribution to the cell theory was made by a botanist named Robert Brown. Brown is known for discovering and naming the cell nucleus. In 1831, Brown was studying fertilization by examining orchids under a microscope. Brown realized that pollen was traveling into and out of ovals in the cell. Brown wrote about these observations, and then two years later in 1833 published them. Brown called these small ovals a cell nucleus.
  • Brown's Model

    Brown's Model
    Robert Brown's model improved upon the ones before it because it examined the inside of the cell and revealed that inside contains a nucleus, a key part of fertilization and development.
  • Schleiden's Contribution

    Schleiden's Contribution
    The fourth contribution to the cell theory was by a German botanist named Matthias Schleiden. Schleiden worked as a professor at the University of Jena and studied plant structures under a microscope. In 1838, Schleiden wrote Contributions to Phytogenesis where he discovered that all plants were composed of cells. He stated that all developments of plants come from cell activity and that the nucleus is the first part of the plant embryo.
  • Schleiden's Model

    Schleiden's Model
    Schleiden's model improved upon the ones before as it showed that all plants are made up of cells and that the nucleus makes up a key part of plant function and development.
  • Schwann's Contribution

    Schwann's Contribution
    The fifth contribution to the cell theory was made by a German physiologist named Theodor Schwann. Schwann was a microscopist who studied animal tissue. Schleiden communicated his finding on plant cells and Schwann also reached the same conclusions in animal cells. In 1839, Schwann stated that all livings were made of cells and that the cell is the most basic unit of structure.
  • Schwann's Model

    Schwann's Model
    Schwann's model improved upon the ones before it as it tied together Schleiden and all the previous models into one statement. Schwann discovered that all living things are composed of cells and began to fully form the cell model.
  • Virchow's Contribution

    Virchow's Contribution
    The sixth contribution made to the cell theory was by Rudolf Virchow, a german scientist. Virchow studied as a professor of pathological anatomy and made a discovery that would become the third part of the cell theory. Virchow found that all cells develop from another cell, even diseased cells come from healthy cells.
  • Virchow's Model

    Virchow's Model
    Virchow's model improved upon the ones before it because it explained the development of these cells and how they asexually reproduce in each organism. This model came to complete the cell theory.