NCERT Solution for Class 10 Science Chapter 9
Heredity and Evolution
NCERT Books for Session 2022-2023
CBSE Board and UP Board
Exercises Questions
Page No-159
Questions No-9
What evidence do we have for the origin of life from inanimate matter?
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A British scientist, J.B.S. Haldane, suggested that life originated from simple inorganic
molecules. He believed that when the earth was formed, it was a hot gaseous mass
containing elements such as nitrogen, oxygen, carbon, hydrogen, etc. These elements
combined to form molecules like water (H2O), carbon dioxide (CO2), methane (CH4),
ammonia (NH3), etc.
After the formation of water, slowly the earth surface cooled and the inorganic molecules
interacted with one another in water to form simple organic molecules such as sugars,
fatty acids, amino acids, etc. The energy for these reactions was provided by solar
radiations, lightning, volcanic eruptions, etc.
This was proved by the experiment of Stanley L. Miller and Harold C. Urey in 1953. They
took a mixture of water (H2O), methane (CH4), ammonia (NH3), and hydrogen gas (H2) in
a chamber and sparks were passed through this mixture using two electrodes. After one
week, 15% of the carbon from methane was converted into amino acids, sugars, etc.
These organic molecules are polymerized and assembled to form protein molecules that
gave rise to life on earth.
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The evidence for the origin of life from inanimate matter, was provided through an experiment, conducted in 1953, by Stanley L. Miller and Harold C. Urey. In experiment, they assembled an atmosphere containing molecules like ammonia, methane and hydrogen sulphide, but no oxygen, over water. This was similar to atmosphere that thought to exist on early earth . This was maintained at a temperature just below 100°C and sparks were passed through the mixture of gases to simulate lightning. At the end of a week, 15% of the carbon from methane, had been converted to simple compounds of carbon including amino acids which make up protein molecules and support the life in basic form. Thus, amply suggesting that life arose afresh on earth.
The famous experiment by Miller and Urey could establish that life originated from inanimate matter. These scientists replicated the conditions which may have existed during the early years of origin of the earth. In that experiment, inorganic substances gave rise to amino acids. Amino acid; we know are the bases of various biomolecules.
this was given by fool-proof experiment by Urey and miller 1953. They simulated the conditions present on primitive earth, in a flask. This contained reducing gases like methane, hydrogen sulphide, hydrogen, carbon etc. The temperature, just below 100 degree c was maintained and current was passed. At the end of a week, it was found that simple biomolecules were formed that included amino acids. This proved that in this manner, biomolecules would have come together and life originated.