Write an essay on origin of life?
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The Origin Of Life
The origin of life on Earth is a scientific problem which is not yet solved. There are plenty of ideas, but few clear facts.
It is generally agreed that all life today evolved by common descent from a single primitive lifeform. It is not known how this early form came about, but scientists think it was a natural process which took place perhaps 3,900 million years ago. This is in accord with the philosophy of naturalism: only natural causes are admitted.
It is not known whether metabolism or genetics came first. The main hypothesis which supports genetics first is the RNA world hypothesis, and the one which supports metabolism first is the protein world hypothesis.
Another big problem is how cells develop. All existing forms of life are built out of cells.
Melvin Calvin, recipient of the Nobel Prize in Chemistry, wrote a book on the subject, and so did Alexander Oparin. What links most of the early work on the origin of life is the idea that before life began there must have been a process of chemical change. Another question which has been discussed by J.D. Bernal and others is the origin of the cell membrane. By concentrating the chemicals in one place, the cell membrane performs a vital function.