2. Hi! I’m Jason and I’ll be with you in
this lesson.
We will tackle about the Studies on
the Origin of Life, Evidence on
the First Forms of Life and The
Three Domains of Life.
3. Studies on The Origin of Life
Many Scientists have dedicated themselves to
finding out how life first appeared on Earth.
All in the name of
curiosity, science
and discovery!
5. Alexander Ivanovich Oparin
Russian
March 2, 1894 – April 21, 1980
a Soviet biochemist notable
for his theories about the origin of life,
and for his book The Origin of Life.
He also studied the biochemistry of
material processing by plants and
enzyme reactions in plant cells.
6. John Scott Haldane
Scottish
May 2, 1860 –March 14/15 ,1936
a physiologist famous for
intrepid self-experimentation
which led to many important
discoveries about the human
body and the nature of gases.
7.
8. Oparin- Haldane Hypothesis
This hypothesis suggested that
if the primitive atmosphere was
reducing (as opposed to
oxygen-rich), and if there was
an appropriate supply of
energy, such as lightning or
ultraviolet light, then a wide
range of organic compounds
might be synthesized.
9. Oparin 1924 Haldane 1929
Hypothesized that:
o The Earth’s atmosphere was extremely
reducing in its early stages of development.
o This means that the atmosphere had an
excess of negative charge and could cause
reducing reactions by adding electrons to
compounds.
o These organic compounds could have
undergone a series of reactions leading to
more and more complex molecules.
o Organic molecules could have formed from
simple inorganic molecules.
o These molecules formed colloid aggregates,
or 'coacervates', in an aqueous environment.
o These coacervates were able to absorb and
assimilate organic compounds from the
environment in a way reminiscent of
metabolism.
o They would have taken part in evolutionary
processes, eventually leading to the first
lifeforms.
Hypothesized that:
o The early stages of Earth’s atmosphere was
reducing, which could catalyze reactions that
would form more complicated organic
molecules from simpler molecules.
o The oceans served as a huge cooking pot
where, powered by the sun or lightning,
chemical reactions could occur in an aqueous
environment to form a huge diversity of organic
compounds.
o The primordial sea served as a vast chemical
laboratory powered by solar energy.
o The atmosphere was oxygen free, and the
combination of carbon dioxide, ammonia and
ultraviolet radiation gave rise to a host of
organic compounds.
o The sea became a 'hot dilute soup' containing
large populations of organic monomers and
polymers.
o Groups of monomers and polymers acquired
lipid membranes, and that further developments
eventually led to the first living cells.
Oparin- Haldane Hypothesis
10. Primordial Soup
Soup sounds
delicious!
Haldane coined the
term 'prebiotic soup' or
'prebiotic atmosphere' that
consisted of an abundance of
methane, ammonia, and
water. This term became a
powerful symbol of the
Oparin-Haldane view of the
origin of life.
12. Harold Clayton Urey
American
April 29, 1893 – January 5, 1981
a physical chemist played a
significant role in the development
of the atom bomb, but may be
most prominent for his contribution
to theories on the development of
organic life from non-living matter.
13. Stanley Lloyd Miller
American
March 7, 1930 – May 20, 2007
a chemist who made landmark
experiments in the origin of life by
demonstrating that a wide range of vital
organic compounds can be synthesized
by fairly simple chemical processes
from inorganic substances.
14. Miller-Urey Experiment
i. Harold Urey and his student Stanley Miller tried to calculate the chemical
constituents of the atmosphere of the early Earth. They based their calculations on
the view that the early atmosphere was reducing.
ii. In order to do this, they simulated early earth atmospheric conditions by creating a
closed system which contained water, methane gas, ammonia, and hydrogen gas.
iii. Urey suggested that his student, Miller should attempt to synthesize organic
compounds in this type of atmosphere.
iv. Miller carried out an experiment in which he passed a continuous spark discharge
at 60,000 Volts through a flask containing the gases identified by Urey along with
water. Furthermore, this electrical current was run through the laboratory set up to
simulate the catalytic source of lightning that was present in the early atmosphere.
v. Miller found that after a week, most of the ammonia and much of the methane had
been consumed. The main gaseous products were carbon monoxide and nitrogen.
vi. In addition, there was an accumulation of dark material in the water. Few of the
specific constituents of this could not be identified, but it was clear that the material
included a large range of organic polymers.
vii. From the results of their experiment, they found that up to 15% of the carbon in the
system was inorganic compounds that had formed in the system.
viii. This conclusion proved that organic molecules could be formed from inorganic
molecules in Earth’s early atmosphere.
16. Analysis of the aqueous solution showed
that the following had also been
synthesized:
25 amino acids
(the main ones being
glycine, alanine and
aspartic acid)
Several fatty acids
Hydroxyl acids
Amide products
25. Fossil Formation
Over long periods of time, particles piled up on
the remains of organisms and eventually
became sedimentary rocks, preserving the
original body patterns of organism.
26.
27. Paleontologists
scientists who study fossils
Examine the age of
fossilized organisms
through radioisotope
dating using radioactive
materials such as the
radioactive components of
potassium-argon.
Found remains of
microscopic living cells,
called microfossils, in
rocks that formed 3.5 billion
years ago after the Earth
cooled and solidified.
28. Microfossils
a fossil or fossil fragment
that can be seen only
with a microscope
existed in mats and
formed layered
structures called
stromatolites.
29. Stromatolites
a calcareous mound built
up of layers of lime-
secreting prokaryotes, or
single-celled organisms,
called cyanobacteria (the
blue-green algae) and
trapped sediment, found
in Precambrian rocks as
the earliest known fossils,
and still being formed in
lagoons in Australasia.
30. Cyanobacteria
Believed by scientists to be the first oxygen-
producing organisms that helped evolve the
Earth’s early atmosphere into one that can
support early life forms
31. Cyanobacteria
As these microorganisms continued
generating oxygen, other photosynthetic
organisms evolved and increased the level of
oxygen in the atmosphere.
This increased the chance of more and more
oxygen reaction ammonia, a reaction that
results in the release of nitrogen into
atmosphere.
37. Life forms exist in different
environmental conditions.
There are organisms in soil, air, and even in
freezing waters or deep sea thermal vents.
This diversity of life constitutes many and
varied lineages of organisms.
Some lineages have gone extinct due to
geological events brought by tsunamis,
volcanic eruptions, extreme fluctuations in
temperature and rising water levels.
38. Carl Richard Woese
American
July 15, 1928 – December 30, 2012
a microbiologist and
biophysicist. He is famous
for defining the Archaea (a
new domain or kingdom of life)
in 1977 by phylogenetic
taxonomy of 16S ribosomal RNA,
a technique pioneered by
Woese which revolutionized
the discipline of microbiology.
39. Domain
the highest taxonomic rank
of organisms in the three-
domain system of
taxonomy
higher than the animal
kingdom classification
43. Archaea
Also known as ancient bacteria because they
resemble the ancient prokaryotes
Their morphological and genetic characteristics
differ from other forms of bacteria.
Lives mostly in extreme environments:
Near rift vents in the deep sea at 100c
Hot springs
Alkaline
Acid waters
Guts of cows
Guts of termites
Guts of some marine life forms which produces
methane
45. Bacteria
Also known true bacteria or simply bacteria
Constitutes a great portion of prokaryotic
microorganisms.
Ecologically diverse, some are found in
Water
Soil
Other organisms
Some are aerobic(needs oxygen), some
are anaerobic.
47. Eukarya
Also known Eukaryotes
Have membrane-bound nucleus
Have eukaryotic cells composed of membrane-
bound organelles
Can be unicellular
Protists
Yeast
Can be multicellular
Plants
Fungi
Animals
