194008
LIFE ON EARTH
- Analysis of the oldest sedimentary
rocks provides evidence for the
origin of life
- The relationship between the
conditions of Early Earth and
the origin of organic
molecules
- Early earth contained no ozone layer so large
amounts of UV radiation reached the earth, the
reason for the absence of no ozone layer was
their was little free oxygen. --> The volcanic
emissions filled the atmosphere with methane,
ammonia, hydrogen, carbon dioxide, carbon
monoxide and small amounts of water vapour.The
violent electrical storms and acidic rain formed the
present warm and mineral - rich oceans.
- There are only two possible ways
organic molecules could have formed
either on earth from simpler molecules,
or by arriving from the cosmos
- Early earth contained no ozone layer so large
amounts of UV radiation reached the earth, the
reason for the absence of no ozone layer was
their was little free oxygen. --> The volcanic
emissions filled the atmosphere with methane,
ammonia, hydrogen, carbon dioxide, carbon
monoxide and small amounts of water vapour.The
violent electrical storms and acidic rain formed the
present warm and mineral - rich oceans.
- Discuss the implications of the existence of
organic molecules in the cosmos for the
origin of life on Earth
- Organic molecules have been found in interstellar
dust. When NASA scientists were investigating
compounds that could be found in comets, moons
and icy planets they exposed the chemicals to UV
radiation which produced many complex organic
compounds. This suggests that the conditions in
interstellar ices could be the site of the production of
the organic chemicals necessary for the origin of life.
- Organic molecules have been found in interstellar
dust. When NASA scientists were investigating
compounds that could be found in comets, moons
and icy planets they exposed the chemicals to UV
radiation which produced many complex organic
compounds. This suggests that the conditions in
interstellar ices could be the site of the production of
the organic chemicals necessary for the origin of life.
- The relationship between the
conditions of Early Earth and
the origin of organic
molecules
- THEORIES ABOUT HOW LIFE STARTED ON EARTH
- SPONTANEOUS GENERATION
- For many generations it was
believed that life spontaneously
arose out of different materials. E.g.
garbage turned into rats, rotting
meat turned into maggots.
- SIGNIFICANCE
- This theory is significant in understanding
the origin of life, because it is untrue. We can
further our understanding by learning from
these errors. In 1862, Louis Pasteur carried
out an experiment by using a flask containing
boiled broth and showed that there was no
spontaneous generation if contamination of
the flask was prevented.
- This theory is significant in understanding
the origin of life, because it is untrue. We can
further our understanding by learning from
these errors. In 1862, Louis Pasteur carried
out an experiment by using a flask containing
boiled broth and showed that there was no
spontaneous generation if contamination of
the flask was prevented.
- For many generations it was
believed that life spontaneously
arose out of different materials. E.g.
garbage turned into rats, rotting
meat turned into maggots.
- Chemicals for life formed on
Earth (Abiotic synthesis in the
Atmosphere and Oceans)
- Haldane and Oparin suggested that Earth had all
the necessary basic chemical components for life
on Earth. They proposed that the early atmosphere
on Earth contained little oxygen, and that the
complex organic molecules could have been
created from UV radiation, electrical discharges,
and heat.
- Haldane and Oparin suggested that Earth had all
the necessary basic chemical components for life
on Earth. They proposed that the early atmosphere
on Earth contained little oxygen, and that the
complex organic molecules could have been
created from UV radiation, electrical discharges,
and heat.
- SPONTANEOUS GENERATION
- UREY MILLER EXPERIMENT
- Urey and Miller set up a simulation of
primitive earth. A mixture of hydrogen,
ammonia, and methane in the form of steam
was continuously electrically discharged for
a week. The experiment resulted in a
solution containing a number of amino acids
and hydroxy acids which are vital
components for living things. Urey and
Miller’s experiment supported Oparin and
Haldane’s theories on the origin of life, which
showed that organic material, could be
formed by raw materials.
- REASONS FOR THIS
- To test the hypothesis of Oparin and
Haldane which stated that conditions on the
primitive Earth favoured chemical reactions
that synthesized organic compounds from
inorganic compounds.
- To test the hypothesis of Oparin and
Haldane which stated that conditions on the
primitive Earth favoured chemical reactions
that synthesized organic compounds from
inorganic compounds.
- Urey and Miller set up a simulation of
primitive earth. A mixture of hydrogen,
ammonia, and methane in the form of steam
was continuously electrically discharged for
a week. The experiment resulted in a
solution containing a number of amino acids
and hydroxy acids which are vital
components for living things. Urey and
Miller’s experiment supported Oparin and
Haldane’s theories on the origin of life, which
showed that organic material, could be
formed by raw materials.
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