1. 1.D.2 Supporting Evidence for Origin of Life Hypotheses Scientific evidence from many different disciplines supports models of the origin of life.

2. Geological evidence provides support for models of the origin of life on Earth..

3. Fossils can be dated back to as long ago as 3.5 bya.

4. Before Darwin, the Earth was thought to be about 6,000 years old. This number was arrived at by using the age at death of Biblical patriarchs from the book of Genesis. PatriarchAgeVerse Adam930Genesis 5:4 Seth912Genesis 5:8 Enosh905Genesis 5:11 Cainan910Genesis 5:14 Mahalalel895Genesis 5:17

5. In 1897, Lord Kelvin calculated that, if the Earth had cooled from a molten state, it must be between 20 and 40 million years old.

6. But 40 million years was not enough time for macroevolution to have occurred….

7. In 1956, C.C. Patterson used the radiometric dating of meteorites, especially the Canyon Diablo Meteorite, to determine that the Earth formed approximately 4.5 billion years ago (bya). (Author’s Family)

8. Today’s accepted age of the earth is 4.56 (4.6) billion years old.

10. The environment was too hostile for life until 3.9 bya, while the earliest fossil evidence for life dates back to 3.5 bya.

11. Chemical experiments, such as the Miller-Urey Experiment, have shown that it is possible to form complex organic molecules from inorganic molecules in the absence of life (abiogenesis).

12. Miller placed the gases he thought would be present in the highly-reducing atmosphere of early Earth into a system. He then ran current into the system to simulate lightning.

13. Gases thought present in Earth’s early atmosphere: methane (CH 4 ), ammonia (NH 3 ), hydrogen (H 2 ) and water (H 2 O). Highly Reducing Atmosphere.

14. At the end of a week, 10-15% of the carbon in the system had been converted to organic molecules, including amino acids.

15. Synthesizing amino acids in this way is a two-step process: CO 2 → CO + OCH 4 + 2[O] → HCN + H 2 OCH 4 + NH 3 → HCN + 3H 2 CH 2 O + HCN + NH 3 → NH 3 + NH 2 -CH 2 -COOH glycine

16. In 1961, Joan Oró found that the nucleotide base adenine could be synthesized from hydrogen cyanide (HCN) and ammonia (NH 3 ) in a water solution.

17. Recently, using modern techniques, even more organic compounds have been discovered in Stanley Miller’s original vials from his experiment; he was more successful than he knew.

18. Molecular and genetic evidence from extant and extinct organisms indicates that all organisms on Earth share a common ancestral origin of life.

19. Last Universal Common Ancestor (LUCA) Characteristics: The genetic code was based on DNA RNA intermediates Genetic code composed of codons that coded for 20 amino acids ATP Enzymes to catalyze chemical reactions Lipid membrane Reproduced by cell division The genetic code was based on DNA RNA intermediates Genetic code composed of codons that coded for 20 amino acids ATP Enzymes to catalyze chemical reactions Lipid membrane Reproduced by cell division

20. Learning Objectives LO 1.32 The student is able to justify the selection of geological, physical, and chemical data that reveal early Earth conditions. [See SP 4.1]