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1
Origin of LifeOrigin of Life
copyright cmassengale
Fundamental Properties of LifeFundamental Properties of Life
Cellular organization. All organisms
consist of one or more c...
Fundamental Properties of LifeFundamental Properties of Life
Growth. All living things assimilate
energy and use it to gro...
Fundamental Properties of LifeFundamental Properties of Life
Regulation. All organisms have
regulatory mechanisms that coo...
5
Aristotle (384 –322 BC)Aristotle (384 –322 BC)
Proposed the theory ofProposed the theory of
spontaneous generationsponta...
6copyright cmassengale
7
Spontaneous GenerationSpontaneous Generation
For centuriesFor centuries,, people basedpeople based theirtheir
beliefsbel...
8
Examples ofExamples of
SpontaneousSpontaneous
GenerationGeneration
copyright cmassengale
9
Example #1Example #1
Observation:Observation: Every year in theEvery year in the
spring, thespring, the Nile River flood...
10
Example #1Example #1
Conclusion:Conclusion: It was perfectlyIt was perfectly
obvious to people back thenobvious to peop...
11
Example #2Example #2
Observation:Observation: In many parts ofIn many parts of
Europe, medieval farmers storedEurope, m...
12
Example #2Example #2
Conclusion: It was obvious toIt was obvious to
them that thethem that the mice camemice came
from ...
13
Example #3Example #3
Observation:Observation: Since there were noSince there were no
refrigerators, the mandatory,refri...
14
Example #3Example #3
Conclusion: Obviously, theObviously, the
rotting meatrotting meat that had beenthat had been
hangi...
15
Abiogenesis RecipesAbiogenesis Recipes
Recipe for bees:Recipe for bees:
Kill a young bullKill a young bull, and, and bu...
16
Abiogenesis RecipesAbiogenesis Recipes
Recipe for mice:Recipe for mice:
Place aPlace a dirty shirtdirty shirt or some r...
17
DisprovingDisproving
SpontaneousSpontaneous
GenerationGeneration
copyright cmassengale
18
Francesco Redi (1668)Francesco Redi (1668)
In 1668, FrancescoIn 1668, Francesco RediRedi, an, an
Italian physician, did...
19
Redi’s ExperimentRedi’s Experiment
Redi usedRedi used open & closedopen & closed
flasksflasks whichwhich contained meat...
20
Redi’s FindingsRedi’s Findings
He found that if a flask wasHe found that if a flask was
closedclosed with a lid sowith ...
21
Redi’s (1626-1697) Experiments
Evidence against spontaneous generation:Evidence against spontaneous generation:
1.1. Un...
22
Results of Redi’s ExperimentsResults of Redi’s Experiments
The results of thisThe results of this
experimentexperiment ...
23
Francesco RediFrancesco Redi
copyright cmassengale
24
Did Redi Use theDid Redi Use the
Scientific Method?Scientific Method?
copyright cmassengale
25
The Scientific MethodThe Scientific Method
ObservationObservation
HypothesisHypothesis
ExperimentExperiment
Accept, Rej...
26
Step 1 - ObservationStep 1 - Observation
There were flies around meatThere were flies around meat
carcasses at the Butc...
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Step 2 - HypothesisStep 2 - Hypothesis
Rotten meat does not turnRotten meat does not turn
into flies.into flies. Only f...
28
Step 3 - TestingStep 3 - Testing
Wide-mouth jarsWide-mouth jars each containing a piece ofeach containing a piece of
me...
29
Step 4 - DataStep 4 - Data
Presence or absence of fliesPresence or absence of flies
and maggots observed in eachand mag...
30
Step 5 - ConclusionStep 5 - Conclusion
Only flies can make more fliesOnly flies can make more flies. In the. In the
unc...
31
DisprovingDisproving
SpontaneousSpontaneous
Generation ofGeneration of
MicrobesMicrobes
copyright cmassengale
32
Anton van Leeuwenhoek (1674)Anton van Leeuwenhoek (1674)
Leeuwenhoek beganLeeuwenhoek began makingmaking andand
looking...
33
Anton van Leeuwenhoek 1632-1723Anton van Leeuwenhoek 1632-1723
copyright cmassengale
34
Leeuwenhoek’s MicroscopeLeeuwenhoek’s Microscope
copyright cmassengale
35
Lazzaro Spallanzani (1765)Lazzaro Spallanzani (1765)
Boiled soups for almost an hourBoiled soups for almost an hour
and...
36
Spallanzani’s ResultsSpallanzani’s Results
copyright cmassengale
37
ConclusionConclusion
CriticsCritics said sealed vials didsaid sealed vials did
not allow enough air fornot allow enough...
38
The TheoryThe Theory
Finally ChangesFinally Changes
copyright cmassengale
39
How Do Microbes Arise?How Do Microbes Arise?
ByBy 18601860, the debate had become so, the debate had become so
heated t...
40
Louis Pasteur (1822-1895)Louis Pasteur (1822-1895)
copyright cmassengale
41
Pasteur's ProblemPasteur's Problem
Hypothesis:Hypothesis: Microbes comeMicrobes come
from cells of organisms on dustfro...
42
Pasteur's Experiment -Pasteur's Experiment - Step 1Step 1
S-shaped FlaskS-shaped Flask
Filled withFilled with brothbrot...
43
Pasteur's Experiment -Pasteur's Experiment - Step 2Step 2
FlasksFlasks boiledboiled
Microbes KilledMicrobes Killed
copy...
44
Pasteur's Experiment -Pasteur's Experiment - Step 3Step 3
Flask left at variousFlask left at various
locationslocations...
45
Pasteur's Experimental ResultsPasteur's Experimental Results
copyright cmassengale
46
Pasteur’sPasteur’s S-shaped flask kept microbesS-shaped flask kept microbes
out but let air inout but let air in..
Prov...
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Biology:Origins of Life

Introduction to Biology.

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Biology:Origins of Life

  1. 1. 1 Origin of LifeOrigin of Life copyright cmassengale
  2. 2. Fundamental Properties of LifeFundamental Properties of Life Cellular organization. All organisms consist of one or more cells—complex, organized assemblages of molecules enclosed within membranes. Sensitivity. All organisms respond to stimuli— though not always to the same stimuli in the same ways. copyright cmassengale 2
  3. 3. Fundamental Properties of LifeFundamental Properties of Life Growth. All living things assimilate energy and use it to grow, a process called metabolism. Plants, algae, and some bacteria use sunlight to create covalent carbon carbon bonds from CO2 and H2O through photosynthesis. Reproduction. All living thing reproduce, passing on traits from one generation to the next. copyright cmassengale 3
  4. 4. Fundamental Properties of LifeFundamental Properties of Life Regulation. All organisms have regulatory mechanisms that coordinate internal processes. Homeostasis. All living things maintain relatively constant internal conditions, different from their environment. Heredity. All organisms on earth possess a genetic system that is based on the replication of a long, complex molecule called DNA. This mechanism allows for adaptation and evolution over time. copyright cmassengale 4
  5. 5. 5 Aristotle (384 –322 BC)Aristotle (384 –322 BC) Proposed the theory ofProposed the theory of spontaneous generationspontaneous generation Also calledAlso called abiogenesisabiogenesis Idea thatIdea that living things canliving things can arise from nonlivingarise from nonliving mattermatter Idea lasted almostIdea lasted almost 20002000 yearsyears copyright cmassengale
  6. 6. 6copyright cmassengale
  7. 7. 7 Spontaneous GenerationSpontaneous Generation For centuriesFor centuries,, people basedpeople based theirtheir beliefsbeliefs onon their interpretations oftheir interpretations of what they sawwhat they saw going on in the worldgoing on in the world around them without testing theiraround them without testing their ideasideas TheyThey didn’t use the scientificdidn’t use the scientific methodmethod to arrive at answers to theirto arrive at answers to their questionsquestions Their conclusions were based onTheir conclusions were based on untested observationsuntested observations copyright cmassengale
  8. 8. 8 Examples ofExamples of SpontaneousSpontaneous GenerationGeneration copyright cmassengale
  9. 9. 9 Example #1Example #1 Observation:Observation: Every year in theEvery year in the spring, thespring, the Nile River floodedNile River flooded areas of Egypt along the river,areas of Egypt along the river, leaving behind nutrient-rich mudleaving behind nutrient-rich mud that enabled the people to growthat enabled the people to grow that year’s crop of food.that year’s crop of food. However, along with the muddyHowever, along with the muddy soil,soil, large numbers of frogslarge numbers of frogs appeared that weren’t around inappeared that weren’t around in drier timesdrier times copyright cmassengale
  10. 10. 10 Example #1Example #1 Conclusion:Conclusion: It was perfectlyIt was perfectly obvious to people back thenobvious to people back then thatthat muddy soil gave rise tomuddy soil gave rise to the frogsthe frogs copyright cmassengale
  11. 11. 11 Example #2Example #2 Observation:Observation: In many parts ofIn many parts of Europe, medieval farmers storedEurope, medieval farmers stored grain in barnsgrain in barns with thatchedwith thatched roofs (like Shakespeare’s house).roofs (like Shakespeare’s house). As a roof aged, it was notAs a roof aged, it was not uncommon for it to start leaking.uncommon for it to start leaking. This could lead toThis could lead to spoiled orspoiled or moldy grainmoldy grain, and of course there, and of course there werewere lots of mice aroundlots of mice around.. copyright cmassengale
  12. 12. 12 Example #2Example #2 Conclusion: It was obvious toIt was obvious to them that thethem that the mice camemice came from the moldy grain.from the moldy grain. copyright cmassengale
  13. 13. 13 Example #3Example #3 Observation:Observation: Since there were noSince there were no refrigerators, the mandatory,refrigerators, the mandatory, daily trip to the butcher shop,daily trip to the butcher shop, especially in summer,especially in summer, meantmeant battling the flies around thebattling the flies around the carcassescarcasses. Typically, carcasses. Typically, carcasses were “hung by their heels,” andwere “hung by their heels,” and customers selected which chunkcustomers selected which chunk the butcher would carve off forthe butcher would carve off for them.them. copyright cmassengale
  14. 14. 14 Example #3Example #3 Conclusion: Obviously, theObviously, the rotting meatrotting meat that had beenthat had been hanging in the sun all day washanging in the sun all day was thethe source of the fliessource of the flies.. copyright cmassengale
  15. 15. 15 Abiogenesis RecipesAbiogenesis Recipes Recipe for bees:Recipe for bees: Kill a young bullKill a young bull, and, and bury itbury it in an upright position soin an upright position so that itsthat its horns protrude fromhorns protrude from the groundthe ground. After a month,. After a month, a swarm of bees will fly outa swarm of bees will fly out of the corpse.of the corpse. copyright cmassengale
  16. 16. 16 Abiogenesis RecipesAbiogenesis Recipes Recipe for mice:Recipe for mice: Place aPlace a dirty shirtdirty shirt or some rags inor some rags in anan open pot or barrelopen pot or barrel containing acontaining a few grains of wheatfew grains of wheat or some wheator some wheat bran, and inbran, and in 21 days21 days, mice will, mice will appear. There will be adult malesappear. There will be adult males and females present, and they willand females present, and they will be capable of mating andbe capable of mating and reproducing more mice.reproducing more mice. copyright cmassengale
  17. 17. 17 DisprovingDisproving SpontaneousSpontaneous GenerationGeneration copyright cmassengale
  18. 18. 18 Francesco Redi (1668)Francesco Redi (1668) In 1668, FrancescoIn 1668, Francesco RediRedi, an, an Italian physician, did anItalian physician, did an experiment withexperiment with fliesflies andand wide-wide- mouth jars containing meatmouth jars containing meat copyright cmassengale
  19. 19. 19 Redi’s ExperimentRedi’s Experiment Redi usedRedi used open & closedopen & closed flasksflasks whichwhich contained meatcontained meat.. HisHis hypothesishypothesis was thatwas that rotten meat does not turnrotten meat does not turn into flies.into flies. HeHe observedobserved these flasksthese flasks toto see in which one(s) maggotssee in which one(s) maggots would develop.would develop. copyright cmassengale
  20. 20. 20 Redi’s FindingsRedi’s Findings He found that if a flask wasHe found that if a flask was closedclosed with a lid sowith a lid so adult fliesadult flies could not get in, no maggotscould not get in, no maggots developed on the rotting meatdeveloped on the rotting meat within.within. In a flaskIn a flask without a lidwithout a lid,, maggots soon were seenmaggots soon were seen in thein the meat because adult flies had laidmeat because adult flies had laid eggs and moreeggs and more adult flies soonadult flies soon appeared.appeared. copyright cmassengale
  21. 21. 21 Redi’s (1626-1697) Experiments Evidence against spontaneous generation:Evidence against spontaneous generation: 1.1. UnsealedUnsealed – maggots on meat– maggots on meat 2.2. SealedSealed – no maggots on meat– no maggots on meat 3.3. GauzeGauze – few maggots on gauze, none on meat– few maggots on gauze, none on meat copyright cmassengale
  22. 22. 22 Results of Redi’s ExperimentsResults of Redi’s Experiments The results of thisThe results of this experimentexperiment disproved the ideadisproved the idea of spontaneous generation forof spontaneous generation for larger organisms,larger organisms, but peoplebut people still thought microscopicstill thought microscopic organisms like algae ororganisms like algae or bacteria could arise that way.bacteria could arise that way. copyright cmassengale
  23. 23. 23 Francesco RediFrancesco Redi copyright cmassengale
  24. 24. 24 Did Redi Use theDid Redi Use the Scientific Method?Scientific Method? copyright cmassengale
  25. 25. 25 The Scientific MethodThe Scientific Method ObservationObservation HypothesisHypothesis ExperimentExperiment Accept, Reject, or Modify hypothesisAccept, Reject, or Modify hypothesis copyright cmassengale
  26. 26. 26 Step 1 - ObservationStep 1 - Observation There were flies around meatThere were flies around meat carcasses at the Butchercarcasses at the Butcher shop.shop. Where do the flies comeWhere do the flies come from?from? Does rotting meat turn intoDoes rotting meat turn into or produce rotting flies?or produce rotting flies? copyright cmassengale
  27. 27. 27 Step 2 - HypothesisStep 2 - Hypothesis Rotten meat does not turnRotten meat does not turn into flies.into flies. Only flies canOnly flies can make more flies.make more flies. copyright cmassengale
  28. 28. 28 Step 3 - TestingStep 3 - Testing Wide-mouth jarsWide-mouth jars each containing a piece ofeach containing a piece of meat were subjected to several variations ofmeat were subjected to several variations of “openness”“openness” while allwhile all other variables wereother variables were kept the same.kept the same. Control groupControl group — These jars of meat were— These jars of meat were set outset out without lidswithout lids so the meat would beso the meat would be exposed to whatever it might be in theexposed to whatever it might be in the butcher shop.butcher shop. Experimental group(s)Experimental group(s) — One group of jars— One group of jars werewere sealedsealed with lids, and another group ofwith lids, and another group of jars had gauze placed over them.jars had gauze placed over them. copyright cmassengale
  29. 29. 29 Step 4 - DataStep 4 - Data Presence or absence of fliesPresence or absence of flies and maggots observed in eachand maggots observed in each jar wasjar was recordedrecorded.. Control groupControl group – flies entered,– flies entered, laid eggs, & maggots emergedlaid eggs, & maggots emerged Gauze coveredGauze covered – flies on gauze,– flies on gauze, but not in jarbut not in jar Sealed jarsSealed jars – No maggots or– No maggots or flies on the meatflies on the meat copyright cmassengale
  30. 30. 30 Step 5 - ConclusionStep 5 - Conclusion Only flies can make more fliesOnly flies can make more flies. In the. In the uncovered jarsuncovered jars, flies entered and laid eggs, flies entered and laid eggs on the meat. Maggots hatched from theseon the meat. Maggots hatched from these eggs and grew into more adult flies. Adulteggs and grew into more adult flies. Adult flies laid eggs on the gauze on the gauze-flies laid eggs on the gauze on the gauze- covered jars. These eggs or the maggotscovered jars. These eggs or the maggots from them dropped through the gauze ontofrom them dropped through the gauze onto the meat. In thethe meat. In the sealed jarssealed jars, no flies,, no flies, maggots, nor eggs could enter, thus nonemaggots, nor eggs could enter, thus none were seen in those jars. Maggots arose onlywere seen in those jars. Maggots arose only where flies were able to lay eggs.where flies were able to lay eggs. ThisThis experiment disproved the idea ofexperiment disproved the idea of spontaneous generation for larger organisms.spontaneous generation for larger organisms. copyright cmassengale
  31. 31. 31 DisprovingDisproving SpontaneousSpontaneous Generation ofGeneration of MicrobesMicrobes copyright cmassengale
  32. 32. 32 Anton van Leeuwenhoek (1674)Anton van Leeuwenhoek (1674) Leeuwenhoek beganLeeuwenhoek began makingmaking andand looking throughlooking through simple microscopessimple microscopes He often made a new microscopeHe often made a new microscope for each specimenfor each specimen HeHe examined waterexamined water and visualizedand visualized tiny animals, fungi, algae, andtiny animals, fungi, algae, and single celled protozoa;single celled protozoa; “animalcules”“animalcules” By end of 19By end of 19thth century, thesecentury, these organisms were calledorganisms were called microbesmicrobes copyright cmassengale
  33. 33. 33 Anton van Leeuwenhoek 1632-1723Anton van Leeuwenhoek 1632-1723 copyright cmassengale
  34. 34. 34 Leeuwenhoek’s MicroscopeLeeuwenhoek’s Microscope copyright cmassengale
  35. 35. 35 Lazzaro Spallanzani (1765)Lazzaro Spallanzani (1765) Boiled soups for almost an hourBoiled soups for almost an hour and sealed containers byand sealed containers by meltingmelting the slender necks closedthe slender necks closed. TheThe soups remained clearsoups remained clear.. Later, heLater, he broke the sealsbroke the seals & the& the soups became cloudysoups became cloudy withwith microbes.microbes. copyright cmassengale
  36. 36. 36 Spallanzani’s ResultsSpallanzani’s Results copyright cmassengale
  37. 37. 37 ConclusionConclusion CriticsCritics said sealed vials didsaid sealed vials did not allow enough air fornot allow enough air for organisms to survive and thatorganisms to survive and that prolonged heating destroyedprolonged heating destroyed “life force”“life force” Therefore,Therefore, spontaneousspontaneous generation remainedgeneration remained thethe theory of the timetheory of the time copyright cmassengale
  38. 38. 38 The TheoryThe Theory Finally ChangesFinally Changes copyright cmassengale
  39. 39. 39 How Do Microbes Arise?How Do Microbes Arise? ByBy 18601860, the debate had become so, the debate had become so heated that theheated that the Paris Academy ofParis Academy of SciencesSciences offered a prizeoffered a prize for anyfor any experiments that would help resolveexperiments that would help resolve this conflictthis conflict TheThe prize was claimed in 1864 byprize was claimed in 1864 by Louis PasteurLouis Pasteur, as he published the, as he published the results of an experiment he did toresults of an experiment he did to disprove spontaneous generation indisprove spontaneous generation in microscopic organismsmicroscopic organisms copyright cmassengale
  40. 40. 40 Louis Pasteur (1822-1895)Louis Pasteur (1822-1895) copyright cmassengale
  41. 41. 41 Pasteur's ProblemPasteur's Problem Hypothesis:Hypothesis: Microbes comeMicrobes come from cells of organisms on dustfrom cells of organisms on dust particles in the air; not the airparticles in the air; not the air itself.itself. Pasteur put broth into severalPasteur put broth into several specialspecial S-shaped flasksS-shaped flasks Each flask wasEach flask was boiled and placedboiled and placed at various locationsat various locations copyright cmassengale
  42. 42. 42 Pasteur's Experiment -Pasteur's Experiment - Step 1Step 1 S-shaped FlaskS-shaped Flask Filled withFilled with brothbroth The special shape wasThe special shape was intended tointended to trap anytrap any dust particlesdust particles containing bacteriacontaining bacteria copyright cmassengale
  43. 43. 43 Pasteur's Experiment -Pasteur's Experiment - Step 2Step 2 FlasksFlasks boiledboiled Microbes KilledMicrobes Killed copyright cmassengale
  44. 44. 44 Pasteur's Experiment -Pasteur's Experiment - Step 3Step 3 Flask left at variousFlask left at various locationslocations DidDid not turn cloudynot turn cloudy Microbes not foundMicrobes not found Notice theNotice the dustdust thatthat collected in the neckcollected in the neck ofof the flaskthe flask copyright cmassengale
  45. 45. 45 Pasteur's Experimental ResultsPasteur's Experimental Results copyright cmassengale
  46. 46. 46 Pasteur’sPasteur’s S-shaped flask kept microbesS-shaped flask kept microbes out but let air inout but let air in.. Proved microbes only come from otherProved microbes only come from other microbes (life from life) -microbes (life from life) - biogenesisbiogenesis The Theory of BiogenesisThe Theory of Biogenesis Figure 1.3copyright cmassengale

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