|Robert Hooke, Antonie van Leeuwenhock, Robert Brown cell biology|
Robert Hooke discovered cork cells in 1665 and named them after the small rooms in a monastery. Antonie van Leeuwenhoek described the blood cells of salmon in 1719 and called their nuclei lumen. Robert Brown described orchid cells in 1831 and observed an opaque area that he called the areola or nucleus.
Units of life
The cell is the common smallest unit of life of all known living things. Some plants and creatures have only one cell; humans have trillions. Cells are complex. Cells in a body are specialized to perform complementary roles. Each cell in a colony of a single-celled organism behaves exactly the same but different single-celled organisms are specialized to perform complementary roles in their ecosystem. Therefore, the purpose of a cell, other than its own perpetuation, is to support the system of which it is a part.
Meditation on purpose
What came first—the organism or its purpose? If these were synchronic, then it would be possible anything that appears spontaneously has its own purpose, which is not to say that anything we create justifies itself. What would it mean if we were to say that a new organism could appear without a purpose? That it could appear but not survive? That it must soon develop a purpose? Possibly purpose is only our rationalization for its function, good or bad, in the system of which it is a part.
The microscope was the key invention for discovering and describing cells. The cell is still being discovered. It didn’t stop with discovery of nuclei, or the Golgi apparatus, or the flagella, cilia, or pili, or the ribosomes, mitochondria, centrioles, chloroplasts, peroxisomes, or lysosomes, or the endoplasmic reticula. We are still working out how these things work.
See also in The book of science:
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