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Page 1 EVOLUTION Page 2 EVOLUTION ORIGIN OF LIFE: ? Stellar distances are measured in light years. ? The universe is very old – almost 20 billion years old. ? The Big Bang theory attempts to explain to us the origin of universe. ? The Big Bang theory: ? A singular huge explosion unimaginable in physical term. ? The universe expanded and hence the temperature came down. ? Hydrogen and Helium formed sometime later . ? The gases condensed under gravitation and formed the galaxies of the present day universe. ? In the solar system of the Milky W ay galaxy , earth was supposedto have been formed about 4.5 billion years back. Page 3 EVOLUTION ORIGIN OF LIFE: ? Stellar distances are measured in light years. ? The universe is very old – almost 20 billion years old. ? The Big Bang theory attempts to explain to us the origin of universe. ? The Big Bang theory: ? A singular huge explosion unimaginable in physical term. ? The universe expanded and hence the temperature came down. ? Hydrogen and Helium formed sometime later . ? The gases condensed under gravitation and formed the galaxies of the present day universe. ? In the solar system of the Milky W ay galaxy , earth was supposedto have been formed about 4.5 billion years back. Condition of early earth: ? Earth formed 4.5 billion years back. ? There was no atmosphere on early earth. ? W ater vapor , methane, carbon dioxide and ammonia released from molten mass covered the surface. ? The UV rays from the sun broke up water into Hydrogen and oxygen and lighter H 2 escaped. ? Oxygen combined with ammonia and methane to form water , CO 2 and others. ? The ozone layer was formed. ? As it cooled, the water vapor fell as rain, to fill all the depressions and form oceans. ? Life appeared 500 Million years after the formation of earth. Page 4 EVOLUTION ORIGIN OF LIFE: ? Stellar distances are measured in light years. ? The universe is very old – almost 20 billion years old. ? The Big Bang theory attempts to explain to us the origin of universe. ? The Big Bang theory: ? A singular huge explosion unimaginable in physical term. ? The universe expanded and hence the temperature came down. ? Hydrogen and Helium formed sometime later . ? The gases condensed under gravitation and formed the galaxies of the present day universe. ? In the solar system of the Milky W ay galaxy , earth was supposedto have been formed about 4.5 billion years back. Condition of early earth: ? Earth formed 4.5 billion years back. ? There was no atmosphere on early earth. ? W ater vapor , methane, carbon dioxide and ammonia released from molten mass covered the surface. ? The UV rays from the sun broke up water into Hydrogen and oxygen and lighter H 2 escaped. ? Oxygen combined with ammonia and methane to form water , CO 2 and others. ? The ozone layer was formed. ? As it cooled, the water vapor fell as rain, to fill all the depressions and form oceans. ? Life appeared 500 Million years after the formation of earth. Origin of life: ? Early Greek thinkers thought units of life called spores were transferred to different planets including earth. ? ‘Panspermia’ is still a favorite idea for some astronomers. ? For a long time it was also believed that life came out of decaying and rotting matter like straw, mud etc.This was the theory of spontaneous generation. ? Louis Pasteur experiment: ? Careful experimentation demonstrated that life comes only from pre-existing life. ? He showed that in pre-sterilized flasks, life did not come from killed yeast while in another flask open to air, new living organism arose from ‘killedyeast’. ? This disproved the theory of spontaneous generation. Page 5 EVOLUTION ORIGIN OF LIFE: ? Stellar distances are measured in light years. ? The universe is very old – almost 20 billion years old. ? The Big Bang theory attempts to explain to us the origin of universe. ? The Big Bang theory: ? A singular huge explosion unimaginable in physical term. ? The universe expanded and hence the temperature came down. ? Hydrogen and Helium formed sometime later . ? The gases condensed under gravitation and formed the galaxies of the present day universe. ? In the solar system of the Milky W ay galaxy , earth was supposedto have been formed about 4.5 billion years back. Condition of early earth: ? Earth formed 4.5 billion years back. ? There was no atmosphere on early earth. ? W ater vapor , methane, carbon dioxide and ammonia released from molten mass covered the surface. ? The UV rays from the sun broke up water into Hydrogen and oxygen and lighter H 2 escaped. ? Oxygen combined with ammonia and methane to form water , CO 2 and others. ? The ozone layer was formed. ? As it cooled, the water vapor fell as rain, to fill all the depressions and form oceans. ? Life appeared 500 Million years after the formation of earth. Origin of life: ? Early Greek thinkers thought units of life called spores were transferred to different planets including earth. ? ‘Panspermia’ is still a favorite idea for some astronomers. ? For a long time it was also believed that life came out of decaying and rotting matter like straw, mud etc.This was the theory of spontaneous generation. ? Louis Pasteur experiment: ? Careful experimentation demonstrated that life comes only from pre-existing life. ? He showed that in pre-sterilized flasks, life did not come from killed yeast while in another flask open to air, new living organism arose from ‘killedyeast’. ? This disproved the theory of spontaneous generation. Oparin – Haldane theory of origin of life: ? Oparin of Russia and Haldane of England proposed that the first form of life could have come from pre- existing non-living organic molecule (e.g. RNA, protein etc.). ? Formation of life was preceded by chemical evolution i.e. formation of diverse organic molecule from inorganic constituents. ? Urey and Miller experiment: ? The conditions on earth were – ? High temperature. ? V olcanic storms. ? Reducing atmosphere containing CH 4 , NH 3 etc. ? ? In 1953, S.L. Miller an American Scientist created similar conditions in a laboratory scale. ? He created electric discharge in a closed flask to raise temperature upto 800oC as it was in primitive earth. ? Used CH 4 H 2 , NH 3 and water vapor inside theflask. ? He observed the formation of amino acids.Read More
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1. What is NEET and how does it relate to evolution? |
2. Can you provide some examples of evolution-related questions that may appear in the NEET exam? |
3. How can a good understanding of evolution improve performance in the NEET exam? |
4. Are there any specific topics within evolution that are frequently asked in the NEET exam? |
5. How can I effectively prepare for the evolution-related questions in the NEET exam? |
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