Cell Theory
Of course you know that Cell is the basic unit of life, all living organisms are composed of one or more cells and all cells arise from pre-existing cells. But do you know the history of cell theory that who contributed? and how was it all concluded in just over two centuries? Based on what things are you told all this?
There is major contribution of several scientists like Mathias Schleiden, Theodor Schwann and Rudolf Virchow in completion of Classical Cell Theory.
Scientists, who contributed
1) Robert Hooke:
In 1665, Robert Hooke observed a piece of cork under a microscope. He observed small box-like structures which he called Cell because of the their resemblance to the small rooms. Robert was the first scientist to use term "Cell".
2) Anton Van Lewvenhook:
Lewvenhook was the first scientist to observe single-celled organisms, which he called animalculus, under higher microscope, he developed himself. Lewvenhook saw protozoa bacteria and sperm cells.
3) Mathias Schleiden:
In 19th century German botanist and scientist Mathias Schleiden, who studied the plant tissues under microscope and concluded, "all plants are composed of cells means Cell is the basic unit of Plant life".
4) Theodor Schwann:
Back to Schleiden in 19th century, a German botanist Theodor Schwann, who further expanded the Schleiden's concept to the animals by studying animal tissues using microscope and concluded, "all animals are composed of cells". He further stated "all living organisms are composed cells and Cell is the basic unit of all living things".
5) Redolf Virchow:
IN 1855, a German physician and scientist who stated "Omnis Cellula e Cellula" meaning " All cells arise from pre-existing cells" based on observations and experiments. This statement of Virchow shock the world opposing the idea of spontaneous generation, it was old concept of that time's people, life comes from non-living things.
Cell Theory
The term "Cell Theory" consists of two words:
Cell: Basic unit of living things.
Theory: Well-sustaintiated explanation of something based on observations and experiments, accepted widely in scientific field.
What is Cell Theory:
The fundamental concepts and principles in Biology to understand cell at advance level, with having strong grip on Cell.
Classical Cell Theory
Classical Cell Theory have explanation of cell based on observations and experiments tested, confirmed, accepted widely and repeated by several scientists specially with contribution of Schleiden, Schwann and Virchow.
It has three major points:
1) All organisms are made up of one or more than one cells.
It mean all living things are either unicellular (have only single cell) like bacteria or multicellular (have more than one cell) like animal and plants.
2) Cell is the Basic unit of life
This explains, cells are the basic units of organisms which carry out all the activities and processes that are necessary for life.
3) All cells arise from pre-existing cells
Virchow all new cells come from old cell through cell division process. When old cell divides new cell is form.
