Transcript Reducing Atmosphere? Slide 1

Logical
Progression
Abiotic
Synthesis of
Monomers
C+H+N+O 
Amino acids
simple sugars
lipids
Early Earth and the Origin of Life
Possible Scenarios
Reducing
Atmosphere
H20,H, CH4,
NH3 +
Energy 
amino acids.
Nucleotides
sugars
Deep Sea
Vents used
iron and
sulfur and hot
water to build
from CO2 and
ammonia
Outer Space
MillerUrey
Comets,
Experi
meteors, space ment
dust showered
earth with
organic
molecules
Abiotic
Synthesis of
Polymers
Concentrated hot monomers form polymers
as evaporation and cooling takes place
Sugar Starch
Minerals, clay, “pyrite” , iron & nickel
sulfides could be used as catalysts
A.A.  Protein
NucleotidesDNA
Origin of
Genetic
Information
“It’s an RNA
world”
Formation of
Protobionts
membrane bound
“cells” with some
properties of life
Supporting Data
Imbedded
organic
compounds
found in
vents
Organics
found in
meteors
and
comets
Monomers form polymers when
dripped on hot sand, rock, or clay
Process fits all scenarios above but differs
in location
Polymers have been found
embedded in deep sea vents
RNA was the first genetic molecule(genotype) Short sequences of RNA can replicate
that functioned also as an enzyme (phenotype) with zinc as catalyst
Natural selection picked the best RNA
molecules as it replicated and “metabolized”
available monomers
RNA can act enzyme like (ribozyme)
RNA types allow natural selection
RNA-amino acid interaction by molecular
cooperation
Abioticly produced molecules
interact to maintain a constant
internal environment showing
irritability and metabolism
3.5 bya fossilized stromatolites (layered
clay rock) formed by 1st prokaryotes
Protobionts called Liposomes form
from lipid, COH, and protein that have:
1. Lipid bilayer that shows osmosis
2. Voltage across membrane
(membrane potential)
3. Engulf and split
4. Simple metabolism
Problems
Timeline of Key Life Events on Earth
Eukaryotes appear!!!
Endosymbiont theory – mitochondria and plastids are
former small prokaryotes that lived in larger cells
Evidence:
Cambrian
Explosion!
Most phyla
form
1. Inner membrane is like those of prokaryotes
2. They replicate like prokaryotes
3. Have cell machinery (i.e. ribosomes) like prokaryotes
4. Similar size, have circular DNA, & RNA sequences like pros
4.6 bya
Earth
forms
4
3.5
Prokaryotes
appear
3
2.5
Prokaryotes
photosynthesize;
O2 revolution by
cyanobacteria,
kills most
prokaryotes,
leads to cell
respiration
2
1.5
1
Multicellular
organisms
appear
(algae & softbodied animals
in water)
0.5
Present
Colonization
of land
~adaptations
to combat
desiccation &
gravity
Reducing Atmosphere
Miller and Urey Experiment 1953 (testing Oparin and Haldane’s idea)
Energy source (Lightning)
Amino Acids and other organic
compounds found in sample
Slide 1
A Model for Gene Replication
RNA WAS THE ORIGINAL GENETIC MATERIAL
Slide 1
“Life-Like” Activities of a Liposome
Simple Reproduction
Simple Metabolism
Slide 1
Cooperation
of RNA and
Proteins
Slide 1
Primitive Earth: Reducing Atmosphere?
Slide 1
Slide 1
Clock Analogy for Key Events in
Earth’s History
Slide 2
Rise of Earth’s Atmospheric Oxygen
Slide 2
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