1. The Origin of Life Notes:
Chapter 14

2. The Beginning: Earth is about 4.6 billion years old
Life began on Earth about 3.5 billion years ago in the ocean

3. Evidence of Life:
Fossils: remains of organisms, found in sedimentary rock
Relative Dating: lower rocks are older than higher ones
Radiometric Dating: using radioactive isotopes in rocks because rate of decay is related to half-life

4. Fossils

5. Relative Dating:

6. Relative Dating:

7. Radiometric Dating:

8. How does life arise?
Spontaneous generation: life from nonliving things
Francesco Redi: disproved theory by showing that flies must come from other flies

9. How does life Arise? Spontaneous generation:
Louis Pasteur: concluded that microorganisms must come from other microorganisms using S-shaped flasks that let in only air = no organisms

10. Biogenesis: life only from other living things
Miller & Urey: showed that organic molecules could have formed the beginning of life

11. The origin of cells:
Anaerobic prokaryotes: lived in an atmosphere with no oxygen

12. The origin of cells:
Aerobic organisms: evolved once photosynthesis released oxygen

13. The origin of cells:
Prokaryotes: cells without a nucleus or organelles
Eukaryotes: cells with a nucleus and organelles
cells grew in complexity once conditions for life improved