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“…sparked by just the right                 combination of physical events                 & chemical processes…”Origin of...
Bacteria Archae- Protista Plantae Fungi   Animalia                          0    Cenozoic                                 ...
What is Life?      First we have to define LIFE…            organized as cells            respond to stimuli          ...
The Origin of Life is Hypothesis      Special Creation             Was life created by a              supernatural or di...
Conditions on early Earth     Reducing atmosphere            water vapor (H2O), CO2, N2, NOx, H2, NH3,             CH4, ...
Electrodes discharge                                                          sparks                                      ...
Stanley Miller                                     University of Chicago       produced    -amino acids  -hydrocarbons-nit...
Origin of Cells (Protobionts)       Bubbles → separate inside from outside                → metabolism & reproduction  Bu...
Dawn of natural selection   Origin of Genetics    RNA is likely first genetic material        multi-functional        c...
Key Events in Origin of Life     Key events in        evolutionary        history of life on        Earth            lif...
Prokaryotes   Prokaryotes dominated life      on Earth from 3.5–2.0 bya       3.5 billion year old        fossil of bacte...
Lynn Margulis   Stromatolites    Fossilized mats of    prokaryotes resemble    modern microbial    coloniesAP Biology
Oxygen atmosphere     Oxygen begins to accumulate 2.7 bya            reducing → oxidizing atmosphere               evid...
~2 bya    First Eukaryotes      Development of internal membranes             create internal micro-environments        ...
Endosymbiosis   Evolution of eukaryotes         origin of mitochondria         engulfed aerobic bacteria, but          ...
Eukaryotic   Endosymbiosis                                   cell with                                                mito...
Theory of Endosymbiosis    Evidence            structural               mitochondria & chloroplasts               resem...
Cambrian explosion    Diversification of Animals            within 10–20 million years most of the major             phy...
AP Biology
AP Biology
Diversity of life & periods of mass extinction             Cambrian             explosionAP Biology
Cretaceous extinction             The Chicxulub impact crater in the             Caribbean Sea near the Yucatan           ...
Early mammal evolution     125 mya mammals        began to radiate        out & fill nichesAP Biology
Classifying Life    Molecular data       challenges 5 Kingdoms              Monera was too diverse                 2 di...
3 Domain system     Domains = “Super” Kingdoms          Bacteria          Archaea              extremophiles = live in...
Kingdom        Kingdom       Kingdom     Bacteria    Archaebacteria   Protista       Kingdom     Kingdom        Kingdom   ...
Any Questions??            Is there life elsewhere?         Does it look like life on Earth?AP Biology                    ...
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09 ch04originoflife2008

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09 ch04originoflife2008

  1. 1. “…sparked by just the right combination of physical events & chemical processes…”Origin of Life AP Biology 2007-2008
  2. 2. Bacteria Archae- Protista Plantae Fungi Animalia 0 Cenozoic bacteria Mesozoic Colonization of land Paleozoic by animals 500 Appearance of animals and land plants 1000 First multicellular PROTEROZOIC organisms 1500 Oldest definite fossilsMillions of years ago of eukaryotes PRECAMBRIAN 2000 Appearance of oxygen in atmosphere 2500 Oldest definite fossils of prokaryotes ARCHEAN 3000 The evolutionary tree of 3500 life can be documented Molten-hot surface of earth becomes cooler with evidence. 4000 The Origin of Life on AP Biology 4500 Formation of earth Earth is another story…
  3. 3. What is Life?  First we have to define LIFE…  organized as cells  respond to stimuli  regulate internal processes  homeostasis  use energy to grow  metabolism  develop  change & mature within lifetime  reproduce  heredity  DNA / RNA  adaptation & evolutionAP Biology
  4. 4. The Origin of Life is Hypothesis  Special Creation  Was life created by a supernatural or divine force?  not testable  Extraterrestrial Origin  Was the original source of organic (carbon) materials comets & meteorites striking early Earth?  testable  Spontaneous Abiotic Origin  Did life evolve spontaneously from inorganic molecules?AP Biology testable
  5. 5. Conditions on early Earth  Reducing atmosphere  water vapor (H2O), CO2, N2, NOx, H2, NH3, CH4, H2S  lots of available H & its electron  no free oxygen low O2 = organic molecules  Energy source do not breakdown as quickly  lightning, UV radiation, volcanic What’s missing from that atmosphere?AP Biology
  6. 6. Electrodes discharge sparks (lightning simulation) Origin of Organic Molecules  Abiotic synthesis  1920 Water vapor CH4 Oparin & Haldane H2 NH3 propose reducing Mixture of gases atmosphere ("primitive Condenser atmosphere") hypothesis  1953 Water Miller & Urey test hypothesis  formed organic Condensed compounds liquid with  amino acids complex, organic  adenine Heated water moleculesAP Biology ("ocean")
  7. 7. Stanley Miller University of Chicago produced -amino acids -hydrocarbons-nitrogen bases -other organics It’s ALIVE! AP Biology
  8. 8. Origin of Cells (Protobionts)  Bubbles → separate inside from outside → metabolism & reproduction Bubbles…Tiny bubbles… AP Biology
  9. 9. Dawn of natural selection Origin of Genetics  RNA is likely first genetic material  multi-functional  codes information  self-replicating molecule  makes inheritance possible  natural selection & evolution  enzyme functions  ribozymes  replication  regulatory molecule  transport molecule  tRNA & mRNAAP Biology
  10. 10. Key Events in Origin of Life  Key events in evolutionary history of life on Earth  life originated 3.5–4.0 byaAP Biology
  11. 11. Prokaryotes  Prokaryotes dominated life on Earth from 3.5–2.0 bya 3.5 billion year old fossil of bacteria modern bacteria chains of one-celledAP Biology cyanobacteria
  12. 12. Lynn Margulis Stromatolites Fossilized mats of prokaryotes resemble modern microbial coloniesAP Biology
  13. 13. Oxygen atmosphere  Oxygen begins to accumulate 2.7 bya  reducing → oxidizing atmosphere  evidence in banded iron in rocks = rusting  makes aerobic respiration possible  photosynthetic bacteria (blue-green algae)AP Biology
  14. 14. ~2 bya First Eukaryotes  Development of internal membranes  create internal micro-environments  advantage: specialization = increase efficiency  natural selection! nuclear envelope endoplasmicinfolding of the plasma reticulum (ER)plasma membrane membrane nucleus DNA cell wall plasma membrane Prokaryotic Prokaryotic Eukaryotic cell ancestor of cell eukaryotic AP Biology cells
  15. 15. Endosymbiosis  Evolution of eukaryotes  origin of mitochondria  engulfed aerobic bacteria, but did not digest them  mutually beneficial relationship  natural selection! internal membrane aerobic bacterium mitochondrion system Endosymbiosis Ancestral Eukaryotic cellAP Biologyeukaryotic cell with mitochondrion
  16. 16. Eukaryotic Endosymbiosis cell with mitochondrion  Evolution of eukaryotes  origin of chloroplasts  engulfed photosynthetic bacteria, but did not digest them  mutually beneficial relationship  natural selection! photosynthetic bacterium chloroplast Endosymbiosis mitochondrion Eukaryotic cell with chloroplast & mitochondrionAP Biology
  17. 17. Theory of Endosymbiosis  Evidence  structural  mitochondria & chloroplasts resemble bacterial structure  genetic Lynn Margulis  mitochondria & chloroplasts have their own circular DNA, like bacteria  functional  mitochondria & chloroplasts move freely within the cell  mitochondria & chloroplasts reproduce independently from the cellAP Biology
  18. 18. Cambrian explosion  Diversification of Animals  within 10–20 million years most of the major phyla of animals appear in fossil record543 myaAP Biology
  19. 19. AP Biology
  20. 20. AP Biology
  21. 21. Diversity of life & periods of mass extinction Cambrian explosionAP Biology
  22. 22. Cretaceous extinction The Chicxulub impact crater in the Caribbean Sea near the Yucatan Peninsula of Mexico indicates an asteroid or comet struck the earth and changed conditions 65 million years agoAP Biology
  23. 23. Early mammal evolution  125 mya mammals began to radiate out & fill nichesAP Biology
  24. 24. Classifying Life  Molecular data challenges 5 Kingdoms  Monera was too diverse  2 distinct lineages of prokaryotes  Protists are still too diverse  not yet sorted outAP Biology
  25. 25. 3 Domain system  Domains = “Super” Kingdoms  Bacteria  Archaea  extremophiles = live in extreme environments  methanogens  halogens  thermophiles  Eukarya  eukaryotes  protists  fungi  plants  animalsAP Biology
  26. 26. Kingdom Kingdom Kingdom Bacteria Archaebacteria Protista Kingdom Kingdom Kingdom FungiAP Biology Plantae Animalia
  27. 27. Any Questions?? Is there life elsewhere? Does it look like life on Earth?AP Biology 2008-2009

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