Summer 2006 Workshop
in Biology and Multimedia
for High School Teachers
How Did Life Originate?
By Kerri Coleman
North Attleboro High School
The Origin Of The Earth
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~4.6 Billion years the earth
was formed
~3.2 Billion years ago the
introduction of Blue-green
cyanobacteria
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Oxygen is produced
Free oxygen begins to
accumulate
Ozone is synthesized
Aerobic metabolism can begin
http://www-cyanosite.bio.purdue.edu/images/lgimages/bloom4.jpg
Image courtesy of Federico Emiliani (Universidad Nacional del Litoral), Mark Schneegurt
(Wichita State University), and Cyanosite (www-cyanosite.bio.purdue.edu)
How Did Life Originate?
 Spontaneous
 Chemical
Generation
Synthesis “Primordial Soup”
 Panspermia
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Spontaneous Generation

Organisms arose spontaneously from
non-living matter
• Example: Maggots arose from rotting meat

Disproved in 1668 by Francesco Redi, an Italian
physician
• Used 3 samples of rotting flesh placed in flasks
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open to air
sealed
covered with gauze
• Maggots were generated in the open container, where flies
had access to meat and were able to lay their eggs
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Results of experiment were not conclusive enough for
some people
 Louis

Pasteur -1864
Experiment showed that life did not
spontaneously appeared
• Meat broth was boiled in a flask to kill
microorganisms
• The neck of the flask was heated and bent into the
shape of an S
• Microorganisms could not get into broth because
they would settle in S shaped neck before contact
with broth
• No growth was in discovered in the broth
• Broth was tilted into the S component and
microorganisms contaminated broth and grew
http://en.wikipedia.org/wiki/Image:Charles_Darwin_1881.jpg#file
“Some warm pond with all sorts of Ammonia, phosphoric salts,
Heat, light, electricity etc…..”
-Charles Darwin, on the origins of life in tidal pools
 Chemical

Synthesis- “Primordial Soup”
Dr. Stanley Miller and Dr. Harold Urey-1953

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ammonia (NH3)
methane (CH4)
water (H2O)
hydrogen (H2)
electricity in an elaborate flask apparatus
• Electricity was passed through the apparatus
• Amino Acids and hydrocarbons were synthesized
http://en.wikipedia.org/wiki/Image:Miller-Urey_experiment_en.png#file
The Formation of Glycine
 Glycine
most abundant amino acids
synthesized in Urey / Miller experiment
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Synthesis occurs in 2 steps
CH2O + NH3+ HCN  NH2CH2CN + H2O
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CH2O = formaldehyde
NH3 = ammonia
HCN = hydrogen cyanide
NH2CH2CN= ammonitrile
H2O = water
NH2CH2CN + 2H2O  NH2CH2COOH + NH3

NH2CH2COOH = glycine

Panspermia- “seeds everywhere”

Life came from space on comets
• Hydrocarbons, amino acids, water(s) and bacteria

September 28, 1969 Murchison, Australia
• Meteorite shower fell

Analysis determined it was carbon rich
• Organic compounds
• Many of the protein Amino Acids found in biological systems
http://meteorites.asu.edu/images/education/allende-big.jpg
Image provided by NASA JPL
Which Theory Do You Think Is
Correct?
 Discuss

within each group
The pros and cons to each theory
• Make sure to use reliable sources on the web and
cite all pages

What evidence is there to support or disclaim
a theory
• For example: Fossil records
 Could
there be another theory?
Sites To Check Out
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http://www.panspermia.org/intro.htm
http://www.accessexcellence.org/WN/NM/miller.html
http://www.accessexcellence.org/WN/SUA02/primordial_soup.html
http://www.chem.duke.edu/~jds/cruise_chem/Exobiology/amino.html
http://meteorites.asu.edu/images/education/allende-big.jpg