(DONE)Module I_1_Origin_of_life, Darwinian Evolution, Historical Perspectives1.pdf

really nice

1. The Big Bang theory of the formation of the universe
•All material in the universe was created in a huge
"explosion," creating and defining matter and space.
•The sudden cooling of the superheated ejecta facilitated the
combination of atomic components into atoms and
molecules.
•These clouds of gasses eventually cooled and formed the
principle components of galaxies -including stars and
planets.

2. Formation of the solar system
A.Theearthformedapproximately4.6BYA(billion
yearsago.)Initially,therewasacloudofgasses
anddustparticles,possiblyoriginatingfromthe
ejectedparticlesofanearbysupernova.
B.Thecloudgraduallycontractedandflattened,
concentratingabout99%ofitsmassinthecenter
withtherestrotatingcounterclockwiseina
flatteneddisk.
C.Asthediskrotated,turbulencewascreated,
causingcondensationofthediskintosmall,
turbulareddies.Thesegraduallyaccreted
togethertoformprotoplanets.
D.Theseprotoplanetsfurtheraccreted,creatingthe
matureplanetsofthesolarsystem.

3. Origin of life
Oparin-Haldanehypothesis:
•TheatmosphereoftheearlyEarthmayhavebeen
chemicallyreducinginnature,composedprimarilyof
gasesshown.
•Insuchareducingatmosphere,electricalactivitycan
catalyzethecreationofcertainbasicsmallmolecules
(monomers)oflife,suchasaminoacids.
•ThiswasdemonstratedintheMiller–Ureyexperiment
byStanleyL.MillerandHaroldC.Ureyin1953.
•Theseorganics,accumulatedinthesurfacewatersof
theocean,forminga"primordialsoup",outofwhich,in
time,lifeinitsmostelementaryformemerged.
Atmo-
sphere
methane
(CH4)
ammonia
(NH3)
water
(H2O)
hydrogen
sulfide
(H2S)
carbon
dioxide
(CO2)
carbon
monoxide
(CO)
phosphate
(PO43-)
molecular
oxygen
(O2)
ozone (O3)
either rare
or absent.

4. Oparin-Haldane model
ThestepsoftheOparin-Haldanemodelaredescribedbelow.
1)Organicmoleculesincludingaminoacidsandnucleotidesaresynthesized
abiotically(withoutlivingcells).
2)Organicbuildingblocksintheprebioticsoupareassembledintopolymersof
proteinsandnucleicacids.
3)Biologicalpolymersareassembledintoaself-replicatingorganismthatfedonthe
existingorganicmolecules.

5. Miller-Urey Experiment
•Miller-Urey apparatus
•Conducted in 1953 by Stanley Miller under the
supervision of Harold Urey;
•The first experiment to test the Oparin-Haldane
theory about the evolution of prebiotic
chemicals and the origin of life on Earth.
The conditions were:
1.Electrical energy provided by spark discharge.
2.Ambient temperature between 0 and 100 C.
3.Sterile conditions to begin with (abiotic environment).
4.A gaseous phase containing reduced sources of carbon (methane), nitrogen (ammonia), oxygen
atoms (water), and hydrogen atoms from any or all of these precursors as well as hydrogen gas.

6. Miller-Urey Experiment
1.Amixtureofmethane,ammonia,hydrogen,andwatervapor,tosimulatetheversion
ofEarth'sprimitive,reducingatmosphere,wasintroducedintoa5-literflaskand
energizedbyanelectricaldischargeapparatustorepresentultravioletradiationfrom
theSun.
2.Theproductswereallowedtocondenseandcollectinalowerflaskwhichmodeleda
bodyofwaterontheEarth'ssurface.
3.Heatsuppliedtothisflaskrecycledthewatervaporjustaswaterevaporatesfrom
lakesandseas,beforemovingintotheatmosphereandcondensingagainasrain.
4.Afteradayofcontinuousoperation,MillerandUreyfoundathinlayerof
hydrocarbonsonthesurfaceofthewater.
5.Afteraboutaweekofoperation,adarkbrownscumhadcollectedinthelowerflask
andwasfoundtocontainseveraltypesofaminoacids,includingglycineand
alanine,togetherwithsugars,tars,andvariousotherunidentifiedorganic
chemicals.
Apparatus used in the Miller-Urey
experiment

7. Biogenesis vs. Abiogenesis
Theory of Abiogenesis
•Nonliving things can be transformed into living things.
•Proposed by Aristotle who observed rotting meat and flies.
•Existed for nearly 2000 years
Example:
•Pond dries up –no fish or frogs
•Rain comes –fish and frogs
Therefore: It rained fish and frogs
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8. Van Helmont
•~300 years ago
•Belgian doctor Jean van Helmont–concluded that mice could be created
from a dirty shirt.
•He placed grains of wheat and a dirty shirt in a container and in 21 days
mice appeared.
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Conclusion: Sweat caused wheat to ferment into mice. Abiogenesis!

9. Redi
•In 1668 Francesco Redi (Italian physician) tested Aristotle’s hypothesis (meat →flies)
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•4 sets of jars with meat
•one set was open (experimental
group)
•one set was sealed (control group)
•Maggots appeared on open jars of
meat
Conclusion: Flies come from flies!
Biogenesis –life from life.
•But, No air in jar, therefore life could
not survive.
•Redi repeated his experiment with a
fine mesh wire –supported Biogenesis
again!

10. Louis Pasteur (1822-1895)
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•1864 –Pasteur developed a swan-neck flask
Experiment:
•Boiled broth, air could enter but microbes
were trapped in curved flask
•Broth remained clear →Biogenesis finally
proven!

11. Darwin’s Voyage
•Charles Darwin became a naturalist, a scientist
who studies nature -British ship HMS Beagle.
•Darwin observed and collected many living and
fossil specimens.
•Darwin made -observations in Galápagos Islands of South America.
•Darwin formed the theory of biological evolution using the
observations.
Theory of Evolution by Natural Selection
What did Darwin see?
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https://youtu.be/-NFfSLlCawE

12. 12

13. What did Darwin observe?
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•Darwin observed differences in beak size
among finches from different islands.
•Many years later, scientists confirmed that
these differences related to the birds’ diets.
•Birds with shorter, heavier beaks could eat
harder foods than those with thinner beaks
could eat.

14. What are the four parts of natural selection?
4 parts of
Natural Selection
Over-
production
Selection
Adaptation
Genetic
Variation
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15. What are the four parts of natural selection?
•Overproduction -a species plant
or animal makes more offspring
than the environment can support.
•Only some will survive into
adulthood.
•Smaller number of them will then
successfully reproduce
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Over-
production

16. •Within a species there are natural
differences, or variations, in traits.
•Due to differences in genetic material.
•Can be passed on from parent to
offspring.
•An important source of variation is a
mutation, or change in genetic material.
What are the four parts of natural selection?
16
Genetic
Variation

17. •Individuals try to get the resources that they need to
survive, including food, water, space, and, in most
cases, mates for reproduction.
•Darwin reasoned that individuals with a particular trait
are more likely to survive long enough to reproduce.
•As a result, the trait is “selected,” becoming more
common in the next generation of offspring.
What are the four parts of natural selection?
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Selection

18. Natural Selection
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19. 19

20. •An adaptationis an inherited trait that
helps an organism survive and reproduce in
its environment.
•As natural selection repeats from
generation to generation, these adaptations
become more common, and new
adaptations may arise.
•Over time, the population becomes better
adapted to the environment.
What are the four parts of natural selection?
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Adaptation

21. How do species change over time?Well-adapted
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