Evolution
Origin of Life
Year Scientist Theory/Experiment Conclusion
1927 Lemaitre Big Bang theory The universe
expanded from
explosion of a
primordial, hot
substance.
1924 Oparin and Chemical evolution preceded Simple organic
− Haldane organic evolution molecules originated
1929 from inorganic
precursors.
1952 Stanley Synthesis of biomolecules by Amino acids were
Miller and creation of similar conditions synthesised from
Urey as primitive atmosphere on ammonia, oxygen,
laboratory scale and carbon dioxide
inside specialised
apparatus.
Urey and Miller experiment
, ● Primitive atmosphere had high temperature, volcanic storms, and
reducing atmosphere, containing CH
4, NH
3, H
2, etc.
● Urey and Miller took the same compounds in a closed flask along with
water vapour at 800C and created an electric discharge.
º
● Formation of biomolecules such as amino acids, simple sugars, fats,
etc. was observed in the flask.
Theories of Evolution
● The theory of special creation or divine intervention was challenged by
Charles Darwin.
● He made observations on his seatrip around the world aboard H.M.S.
Beagle and concluded that all existing living forms share similarities among
themselves and also with other life forms, which existed millions of years
ago of which many are extinct.
● The evolution of life forms has been gradual and those life forms
better fit in environments that leave more progeny. This is called
natural selection and is a mechanism of evolution.
● Alfred Wallace working in the Malay Archepelago also came to the
same conclusion.
Evidences of Evolution
Origin of Life
Year Scientist Theory/Experiment Conclusion
1927 Lemaitre Big Bang theory The universe
expanded from
explosion of a
primordial, hot
substance.
1924 Oparin and Chemical evolution preceded Simple organic
− Haldane organic evolution molecules originated
1929 from inorganic
precursors.
1952 Stanley Synthesis of biomolecules by Amino acids were
Miller and creation of similar conditions synthesised from
Urey as primitive atmosphere on ammonia, oxygen,
laboratory scale and carbon dioxide
inside specialised
apparatus.
Urey and Miller experiment
, ● Primitive atmosphere had high temperature, volcanic storms, and
reducing atmosphere, containing CH
4, NH
3, H
2, etc.
● Urey and Miller took the same compounds in a closed flask along with
water vapour at 800C and created an electric discharge.
º
● Formation of biomolecules such as amino acids, simple sugars, fats,
etc. was observed in the flask.
Theories of Evolution
● The theory of special creation or divine intervention was challenged by
Charles Darwin.
● He made observations on his seatrip around the world aboard H.M.S.
Beagle and concluded that all existing living forms share similarities among
themselves and also with other life forms, which existed millions of years
ago of which many are extinct.
● The evolution of life forms has been gradual and those life forms
better fit in environments that leave more progeny. This is called
natural selection and is a mechanism of evolution.
● Alfred Wallace working in the Malay Archepelago also came to the
same conclusion.
Evidences of Evolution
