describe about evolutionary process of life through chemical and biological

1. Chemical & Biological Origin of Life
BY- UTTARAN MODHUKALYA
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2. CONTENT
Introduction
Chemical evolution
Biological evolution
SUMMARY OF THE ORIGIN OF LIFE
REFERANCE
CONCLUSION
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3. INTRODUCTION
 No one knows exactly when and how life
first appear on the earth. Different
hypothesis and theories have been put
forwarded concerning the origin of life by
the modern as well as the earlier
scientist. In the past it was believed that
the presence forms of plants and animals
have been their from the beginning of
earth and would continued to exist.
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4. Chemical evolution
1. The Atomic Phase :Early
earth had innumerable
atoms of all those elements.
e.g, hydrogen, carbon,
nitrogen sulpher,
phosphorus etc. Which are
essential for formation of
protoplasm.
2. Formation of inorganic
molecule : Free atom
combine and form
H2,N2,H2O,CH4,NH3,CO2.
Hydrogen is most numerous
and reactive in primitive
atmosphere and it combine
with oxygen, nitrogen etc.
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5. Chemical evolution
 Formation of simple organic molecule(monomer): The
inorganic molecule interacted and produced simple organic
molecule such as Simple sugar(ribose, deoxyribose,
glucose etc),Nitrogenous base(purine, pyrimidines),
amino acid, glycerol, fatty acid etc.
Stanley Miller in 1953 demonstrated it clearly that
ultraviolet radiation or electrical discharge or heat or a
combination of these can produce complex organic
compounds from a mixture of methane, ammonia,
hydrogen and water vapour . The ration of methane,
ammonia, hydrogen is 2:2:1 respectively.
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6. Water vapor
Condensed
liquid with
complex,
organic
molecules
Condenser
Mixture of gases
("primitive
atmosphere")
Heated water
("ocean")
Electrodes discharge
sparks
(lightning simulation)
Water
Origin of Organic Molecules
*Abiotic synthesis
 1920
Oparin & Haldane
propose reducing
atmosphere
hypothesis
 1953
Miller & Urey
test hypothesis
 formed organic
compounds
 amino acids
 adenine
CH4
NH3
H2
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7. Stanley Miller
University of Chicago
Produced-
1. amino acids
2.hydrocarbons
3.nitrogen bases
4.other organics
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8. Chemical evolution
 Formation of complex organic molecule(macromolecule):A
variety of amino acid, fatty acid, hydrocarbon, purine and
pyrimidines bases, simple sugar and other organic
compounds accumulated in the ancient seas. In the primeval
atmosphere electrical discharge, lightning, solar energy, ATP
and polyphosphates might have provided the source of
energy for polymerization reactions of organic synthesis.
S.W. Fox demonstrated that if a nearly dry mixture of
amino acid is heated then polypeptide molecules are forms.
Similarly simple sugars could form polysaccharide,
nucleotide can form DNA, RNA, fatty acid can form fats etc.
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9. Chemical evolution
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10. BIOLOGICAL EVOLUTION
 As a result of chemical evolution various macromolecules and
nucleoproteins were found which remained dissolved in ocean .
The various molecules form some colloidal masses as insoluble
droplets. These droplets aggregate to form a large colloidal system
called coacervates and Fox’s microspheres which posses some of
the basic prerequisites of protocells.
 A] Coacervates: It can selectively absorb chemicals from the
surrounding water and incorporate them into their structure.
These nonliving structure that led to the formation of the first
living cells from which the more complex cells have today evolved.
Oparin speculated that a protocell consisted a carbohydrates,
proteins, lipids and nucleic acids that accumulated to form a
coacervate.
 B] Microspheres: It is a nonliving collection of organic
macromolecules with double layered outer boundary. It is formed
by proteinoides(protein like structure consist of branched chains
of amino acids). Microspheres swells or shrink depending on the
osmotic potential in the surrounding solution. Using ATP,
microsphere can from polypeptide and nucleic acid and can
absorb material from the surrounding medium. 10

11. BIOLOGICAL EVOLUTION
 Origin of prokaryotes : It was originated from protocell
about 3.5 billion years ago in the sea. The atmosphere was
anaerobic due to absence of oxygen. It is absence of nuclear
membrane, cytoskeleton.
 Mode of nutrition :
A] heterotrophs: The earliest prokaryotes presumbly obtained
energy by the fermentation of organic molecules from the sea.
B] Autotrophs: They can produce their own food by
chemosynthesis
C] Chemoautotrophs: It prepared organic food by using energy
released during certain inorganic chemical reaction.
D] Photoautotrophs: Evolution of chlorophyll molecule enabled
certain protocells to utilize light energy and synthesize
carbohydrate and they were anaerobic photoautotrophs.
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12. BIOLOGICAL EVOLUTION
 Oxygen revolution and ozone layer formation : As the
no. of Photoautotrophs increase oxygen release in the
sea and atmosphere the reaction occur given below-
CH4+2O2 CO2+2H2O
4NH3+3O2 2N2+6H2O
As oxygen accumulated in the atmosphere, the
ultraviolet light changed some of oxygen into ozone.
The ozone formed a layer in the atmosphere, blocking
the ultraviolet light and leaving the visible light as the
main source of energy.
2O2+O2 2O3
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13. BIOLOGICAL EVOLUTION
 Origin of eukaryotes: Eukaryotes developed from
primitive prokaryotic cells about 1.5 billion years ago. Two
types of view regarding in the origin of eukaryotes-
A] Symbiotic origin : Some anaerobic predator host cells
engulfed primitive aerobic bacteria but did not digest them.
These aerobic bacteria established themselves inside the
host cells as symbionts. Such predator host cells became the
first eukaryotic cells. Animal cells are only engulfed the
aerobic bacteria by predator host cell. But in case of plant
eukaryotic cell the predator engulf both the aerobic bacteria
and blue green algae.
B] Origin by invagination : The cell organelles of eukaryotic
cells might have originated by invagination of surface
membrane of primitive prokaryotic cells.
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14. BIOLOGICAL EVOLUTION
infolding of the
plasma membrane
DNA
cell wall
plasma
membrane
Prokaryotic
cell
Prokaryotic
ancestor of
eukaryotic
cells
Eukaryotic
cell
Endoplasmic reticulum
nuclear envelope
Nucleus
plasma
membrane
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15. Origin of plant and animal cell
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Eukaryotic
cell with
mitochondrion
photosynthetic
bacterium
Endosymbiosis
Eukaryotic cell with
chloroplast & mitochondrion
chloroplast
mitochondrion
internal membrane
system aerobic bacterium
mitochondrion
Fig: Symbiosis origin of eukaryotic cells

16. Origin of multicellular organism
 Once the unicellular organisms were developed the
cells could gather to form colonies. Later cell
differentiation occurred to form the multicellular
organisms. The latter gave rise to all the different
forms of life by gradual modification over the ages.
The advantage of multicellularity is based on division
of labour between the component cells. First
multicellular organism was algae formed in 1.5 b.y.a.
.After “snowball earth”(long ice age), the Cambrian
explotion occurred creating all the phyla that currently
exist and 1st predator-prey interaction.
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17. SUMMARY OF THE ORIGIN OF LIFE
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18. REFERENCE
 TRUEMAN ELEMENTARY BIOLOGY
 EXPLORING BIOLOGY
 INTERNET
 OUR RESPECTED TEACHER’S NOTE
 A BOOK OF LIFE SCIENCE
 WIKIPEDIA
 A BOOK OF EVOLUTION
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19. CONCLUSION
 From the above discussion we can concluded
that in case of origin of life, first inorganic
atoms are combines and form inorganic
molecule. After that forms the organic
molecule and later forms the proto cell. The
proto cell then develops into the prokaryotic
cell and by engulfing of bacteria forms the
eukaryotic cells are form. i.e, firstly chemical
evolution and then biological evolution is
occur. 19

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