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Cell Theory
Scientists
Robert Hooke
Who: Robert C. Hooke
When: 1653
Consignment from the
King, Personal curiosity
Methods: Looked at a thin
slice of cork through a
microscope at 50x
Institution: The Royal
Society
Where: London, England
Funding: King Charles III
Technology: Microscope
Robert Hooke
Robert C. Hooke (1635-1703) was 26 years old when he
joined the Royal Society For Scientists. A self-educated
child prodigy, he showed technical aptitude by recreating
the entire inner workings of a clock out of wood, then
assembling it to run. Hooke also taught himself technical
drawing, a skill he used to capture observations through
his microscope.
Hooke went beyond his commission and looked at
everything from fabric, leaves, mica, glass, flint, and even
frozen urine. When Hooke viewed a thin cutting of cork he
discovered empty spaces contained by walls, and termed
them pores, or cells. The term cells stuck and Hooke
gained credit for discovering the building blocks of all life.
Hooke viewed
a thin cutting
of cork and
discovered
empty spaces
contained by
walls which he
termed cells.
Matthias Schleiden
Who: Matthias Schleiden
When: 1838
Methods: Drawing upon
published information
Institution: University of
Berlin
Where: Berlin, Germany
Matthias Schleiden
Matthias Jakob Schleiden, a German botanist, concluded that all
plant tissues are composed of cells and that a plant arose from a single
cell. He declared that the cell is the basic building block of all plant matter.
This statement of Schleiden was the first generalizations concerning cells.
Born in Hamburg and educated in law at Heidelberg, Schleiden
left law practice to study botany, which he then taught at the University of
Jena from 1839 to 1862. Schlieden investigated plants microscopically and
conceived that plants were made up of recognizable units, or cells.
Plant growth, he stated in 1837, came about through the
production of new cells, which, he speculated, where created from the
nuclei of old cells. Although later discoveries proved him wrong about the
role of the nucleus in mitosis, or cell division, his conception of the cell as
the common structural unit of plants had the profound effect of shifting
scientific attention to living processes as they happened on the cellular
level-a change that initiated the field of embryology. A year after Schleiden
published his cell theory on plants, his friend Schwann extended it to
animals, thereby bringing botany and zoology together under one unifying
theory.
Theodor Schwann
Who: Theodor Schwann
When: 1839
Methods: Drawing upon
published information
Institution: University of Berlin
Where: Berlin, Germany
Theodor Schwann
Theodor Schwann, a German biologist, reached the same
conclusion as Schleiden about animal tissue being composed
of cells, ending speculations that plants and animals were
fundamentally different in structure. Schwann described
cellular structures in animal cartilage. He pulled existing
observations together into theory that stated:
1.
2.
Cells are organisms and all organisms consist of one or more cells.
The cell is the basic unit of structure for all organisms and that
plants and animals consist of combinations of these organisms
which are arranged in accordance with definite rules. In other
words, the cell is the basic unit of life. This statement was the
second generalization concerning cells and is the most important
in the development of biology. It became known as the cell
theory.
Schwann applied the cell theory of the German
botanist Matthias Jakob Schleiden to the evolution of animal
life. He also demonstrated that the mature tissues of all animals
are traceable to single cells.
Rudolf Virchow
Who: Rudolf Virchow
When: 1858
Why: To advocate and
popularize the theory
that all cells form from
other cells
Methods: Drawing
upon published
information
Institution: University of
Berlin
Where: Berlin, Germany
Rudolf Virchow
Virchow was a man who worn many hats. He was a doctor,
anthropologist, pathologist, biologist and politician. Virchow was
from a farming family, he studied medicine and chemistry in Berlin
at the Prussian Military Academy. In 1845, while working as an intern
alongside Robert Froriep, Virchow published his first scientific
paper. Unlike his German peers, Virchow felt that clinical
observation, animal experimentation to determine causes of
diseases, especially at the microscopic level, were the basic
principles of investigation in medical sciences. He thought the cell
was the basic unit of the body that had to be studied to understand
disease.
Virchow's most widely known contribution was his development on
cell theory. He was cited for being the first to recognize leukemia
cells and that all cells came from pre-existing cells. At first
Virchow did not believe the evidence for cell division, that it only
occurs in certain types of cells.
Rudolph Virchow proposed the third and final part of cell theory,
and in completion of the puzzle, he received the Copley Medal in
1892.
Cell Theory Timeline