Transcript Origin of Life on Earth

Worms arise from the mud?
Mice from dirty rags and corn?
Bacteria from broth
Redi- Needham- Spallanzani- Pasteur- and
Leeuwenhoek
Life comes from life
5
bya- solar system –
swirling mass of dust
and gas.
 Matter collapsed –
sun
4.6 bya- Earth formed
3rd rock from the sun
1.
2.
3.
Hostile Earth
Bombarded by
meteorites
Very hot- collisions
and compression
Volcanic eruptions
Atmosphere: water
vapor, Helium,
Nitrogen gas and
Hydrogen gas.
In timeTemperatures cooled below
boiling point.
Water vapor condensed
Rain fell and filled the earths
depressions.
3.5 bya
Stromatolites
Microfossils
Found on rocky coasts
& shallow seas
Formed from sediment
build-up in Bluegreen algae
Scientist agree:
1. Formation of simple organic compounds
2. Formation of complex organic
compounds like proteins
3. Enclosure of complex organic
compounds
4. Linking of chemical reactions to growth,
metabolism, reproduction
All the elements on earth have been
present for 4.6 billion yearsSource:
1. Atmosphere
2. volcanoes and deep ocean vents
How could they come together to form
organic molecules?
Cradle of life
Oparin- 1923
 Earths
Hypothesis
early atmosphere contained
methane and ammonia
 Intense heat could cause these gases to
form simple organic molecules- amino
acids
 Earth’s cooling- molecules fell into water
 Over time- compounds entered complex
chemical reactions- form proteins
Based upon Oparin’s
hypothesis
 Created
a chamber to
hold gases
 As gases circulatedsparks of energy
were added to
energize chemical
reactions.
Results:
Gases  to Simple organic
molecules like :
ATP, amino acids and
nucleotides.
Simple  complex organic
molecules
Other experiments:
Amino acids could form
chains when heated in an
atmosphere.
So…. It is possible that
other polymers like
complex carbs. and
nucleic acids could have
formed?
Experiments prove
that:
Fox- University of
Miami
Hot substrates such as
clay, sand, and rock
A group of amino acids
formed a
polypeptide on a hot
surface like clay.
Will cause chemical
bonds to occur
between monomers.
Protobionts:
Droplets of biomolcules
surrounded by a membrane.




Selectively permeable
membrane
Grow by taking in molecules
Divide when they reach a
certain size
Swell and shrink - osmotically
1. Coacervates- contain several
types of biomolecules
2. Microspheres- contain one
type of biomolecule
Over time, could these
droplets have developed the
capabilities necessary for
life?
Tide pools
A mixture of DNA and
lipids exposed to
periods of wet and dry.
1.
2.
3.
hydrated- mixture of
DNA and lipids are
intertwined.
When dry- lipids
sandwiched DNA
When rehydratedDNA was enclosed in
lipids.
Replication is the
difference between
life and non-life.
Hypothesis 1st genes were short
pieces of RNA.
 Replication on clay
surface-
Experiment:
 RNA molecules can
polymerize
spontaneously
without and enzyme
 When RNA is added
to a solution containg
RNA monomers, new
complimentary RNA
molecules assemble.
RNA can act as a
catalyst.
Probably:
Energy from glycolysis
Unicellular, anaerobic,
heterotophic
prokaryotes.
Floated in early seas
running into and
consuming organic
molecules in the
water.
Competition lead to:
Photoautotrophs:
Autotrophic prokaryotes

1st. Chemosynthetic
autotrophs

2nd. Photosynthetic
autotrophs


Produced Oxygen as a
waste product
Oxygen gas slowly fills
the atmosphere
Ozone forms
Life can move on to
land.