-
330 BCE
Aristotle
384 BC
- Did many experiments
- First to theorize that each germ came from another
- Each gene has a "definate parent and a similar offspring" -
Period: 200 BCE to
Timespan
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Zacharias Jansen
1590
- Invented the first compound microscope
- Allowed scientists to cite and observe cells
- Proved all living things are made of cells -
Jan Baptist van Helmont
1643
-Made the theory of spontaneous generation
-living things just randomly appeared like magic. -
Robert Hooke
1665
- First person to observe cells
- Created the term cell while observing a piece of cork
- Cells came from the term cell which is a monk's living quarters
- Led to greater understanding of cells and life
- Proved all living things are made of cells
- Cork is a living thing -
Anton van Leeuwenhoek
1674
- Invented a lens for the microscope to magnify 270%
- First to see spermotoza and protozoa
- His findings supported cell theory as a whole -
Lorenz Oken
1802
- Proved all living things originate and consist of cells
- Developed a new system of animal classification based on evolution
- Believed in both the ideas that all living organisms have cells and cells are formed by pre-existing cells -
Robert Brown
1833
- Observed plant cells
- Discovered/named the cell nucleus
- Stressed its importence in reproduction and recognized its signifigance as an essential organelle
- Proved all living things are composed of cells -
Matthias Schleiden
1838
- Obseverd plants on a microscopic level
- All plant tissues are composed of cells
- Embryonic plants arise from single cells
- Cells are the building blocks of plant matter
- All plants grew throught the production of new cells
- Believed that new cells in plants were formed form the nucleus of old cell -
Theodor Schwann
1839
- Reached same conclusion as Schleiden but in animals
- Ended controversy that plants and animals were fundamentally different
- Examined the cellular structure in animal cartilage and determined that cells are the basic unit of life -
Albrecht von Roelliker
1840
-Discovered through the help of powerful microscopes that the sperm and egg were composed of cells
-humans are formed of cells from beginning to end. -
Rudolf Virchow
1855
- Every cell comes from a pre-existing cell
- First to demonstrate that the cell theory applies to both normal and diseased cells
- Added to the cell theory and strengthened the theory that cells exist from pre-existing cells -
Louis Pasteur
1860
- Conducted experiments to disprove spontaneous generation.
- Used S shaped beaker to trap microorganisms and prevent them from entering broth
- Suggested the germ theory which states that microorganisms cause infectious diseases
- Proved the cell theory by showing that spontaneous generation does not exist and all cells are formed by pre-existing cells
