1. Chapter 14
History of Life

2. Origin of Life
Spontaneous Generation — Life from nonlife Francesco Redi — ( )
Meat Covered meat
Maggots No maggots

3. Lazzaro Spallanzani— (1729-1799) Uncovered Broth Covered Broth
Cloudy Broth Unclouded Broth
Cloudiness comes from microorganisms

4. Louis Pasteur—( )
Flask: Tilted flask:
S shaped neck S shaped neck
No microorganisms Microorganisms
Biogenesis - Life comes from Life

5. Earth’s History 5 billion years ago the earth was formed
3.9 billion years ago the oldest rocks were formed
3.5 billion yeas ago the first fossils formed

6. Fossils
Fossils - most formed from hard part of body - shell, bones, teeth may be trapped in resin (sap) or ice, tar, mud
Three types of fossils: 1. Imprints –film of carbon remains 2. Molds - impression of object 3. Casts - sediments fill a mold

7. Molds - impression of object
Position in sedimentary rock

8. Dating Fossils Position in sedimentary rock
Carbon 14 dating—1/2 life of C-14, 5700 years Ratio of C-12/C-14 is constant Ratio when an organism dies same as atmosphere when it died, makes it possible to date thing up to 50,000 years old
Potassium & Uranium dating - longer ½ life makes it possible to date objects older than 50,000 years old

9. First Organic Compounds
Alexander Oparin — ( ) Theorized that the original atmosphere of the Earth consisted of NH3 (ammonia), H2 (hydrogen gas), H20 Water Vapor, and compounds made of Carbon & Hydrogen. Lightening and the heat of the Earth created simple organic molecules
Miller & Urey - Tested Oparin’s theory p produced simple organic compounds supporting the theory

10. First Organisms
First Prokaryotes – 1 celled organism with no nucleus Anaerobic — no 02, Autotrophic make own food, or heterotrophic
Endosymbiosis Theory- Lynn Margulis (I938-) Several prokaryotes lived together in symbiotic relationship = first eukaryotes p. 290