1. Formation of our Universe 10-20 billion years ago Formation of our solar system and Earth 4.6 billion years ago Cooling of Earth, formation of oceans, hospitable environs 3.9 billion years ago Formation of cenancestor (LUCA) 3.6 to 4.1 billion years ago Emergence of 3 Domains: Archaea, Bacteria, Eukarya 2.5 billion years ago common ancestor (cenancestor/LUCA) Bacteria Eukary a Archaea Early Earth and Origins of Life

2. 1. Abiotic synthesis (inorganic --> organic) Oparin & Haldane hypothesis (1920s) Urey & Miller (1953) Joining of monomers > polymers Fox (1950s-60s) Packaging of protobionts Oparin’s hypothesis (1920s) Fox (1950s-60s) Self-replicating molecules Cech (1980s) Altman (1980s) Hypotheses of Early Life: cenancestor formation (4 main phases)

3. 1. Abiotic synthesis (inorganic > organic) Oparin & Haldane hypothesis (1920s) Urey & Miller (1953) Joining of monomers > polymers Fox (1950s-60s) Packaging of protobionts Oparin hypothesis (1920s) Fox (1950s-60s) Self-replicating molecules Cech (1980s) Altman (1980s) Hypotheses of Early Life: Cenancestor formation (4 main phases)

4. Abiotic synthesis: Early Earth environment Oparin & Haldane Hypothesis (1920s) No O 2 Reducing environment favors synthesis CO 2 NH 3 H 2 H 2 O CH 4 H 2 S Lightning, UV irradiation, etc. “Primordial Soup” hypothesis

5. Stanley Miller, Age 23 Miller and Urey, 1953 Bottom flask heated > vaporization Electric sparks applied to top flask Ran for 1 week Results: Water became pink, then red, and turbid Analysis of contents reveals organic compounds amino acids (alanine and glycine) sugars lipids building blocks of nucleic acids

6. 1. Abiotic synthesis (inorganic > organic) Oparin & Haldane hypothesis (1920s) Urey & Miller (1953) Joining of monomers > polymers Fox (1950s-60s) Packaging of protobionts Oparin hypothesis (1920s) Fox (1950s-60s) Self-replicating molecules Cech (1980s) Altman (1980s) Hypotheses of Early Life: Cenancestor formation (4 main phases)

7. Sydney Fox: Simple polymers (1950s) amino acids (monomers) Heat Hot sand, clay, rock polypeptides (polymers) *dripped amino acids over hot sand, clay, rock and found that given the proper conditions, monomers would join to form polymers *in same manner were able to form proteinoids (a type of protobiont) as outlined in next section

8. 1. Abiotic synthesis (inorganic > organic) Oparin & Haldane hypothesis (1920s) Urey & Miller (1953) Joining of monomers > polymers Fox (1950s-60s) Packaging of protobionts Oparin hypothesis (1920s) Fox (1950s-60s) Self-replicating molecules Cech (1980s) Altman (1980s) Hypotheses of Early Life: Cenancestor formation (4 main phases)

9. Protobionts: aggregates of abiotically produced molecules surrounded by membrane Oparin (1920s) coined the term “bubble hypothesis” Sydney Fox (1950s-60s) demonstrated with proteins as “membrane” (proteinoids) Maintain internal chemical environment separate from surroundings Some properties associated with life reproduction- can “duplicate” & “divide” “metabolism”- can take up substances; can set up simple metabolic reactions inside

10. Protobionts coacervates, proteinoids, micelles, liposomes, microspheres synonyms and different names depending on what “membrane” is made of:

11. Liposome formation Amphiphilic lipids form micelles and liposomes Hydrophilic (water-loving) heads and hydrophobic (water-hating) tails self- assemble in agitated H 2 O Can grow and shrink in the presence of salts

12. Protobionts: fossil evidence 3.5 billion years ago

13. 1. Abiotic synthesis (inorganic > organic) Oparin & Haldane hypothesis (1920s) Urey & Miller (1953) Joining of monomers > polymers Fox (1950s-60s) Packaging of protobionts Oparin hypothesis (1920s) Fox (1950s-60s) Self-replicating molecules Cech (1980s) Altman (1980s) Hypotheses of Early Life: Cenancestor formation (4 main phases)

14. Ribozymes = RNA as an enzyme RNA-directed catalysis discovered in nature (1980s) Tom Cech - self splicing introns Syndey Altman - tRNA cleavage Ribozymes & the “RNA World”

15. Self-replicating Ribozyme (2001) “RNA polymerase ribozyme” made in lab “R

16. RNA may have been the first genetic material RNA simpler than DNA error-prone polymerization produces “mutations”- diversity in “offspring” natural selection of “offspring” with more efficient catalysis leads to “evolution” idea that enzymatic activity appears first and specificity evolves later Ribozymes & the “RNA World”

17. Modern precedent for idea of RNA as self- replicating genetic material RNA viruses: RNA as sole genetic material (no DNA intermediates) RNA molecules involved in many types of polymerization in “modern” cells Telomere (DNA end structures) replication Ribosome and tRNA (Translation)

18. What is missing from early Earth atmosphere that we need in order to progress to the 3 Domains?

19. Formation of our Universe 10-20 billion years ago Formation of our solar system and Earth 4.6 billion years ago Cooling of Earth, formation of oceans, hospitable environs 3.9 billion years ago Formation of cenancestor (LUCA) 3.6 to 4.1 billion years ago Emergence of 3 Domains: Archaea, Bacteria, Eukarya 2.5 billion years ago common ancestor (cenancestor/LUCA) Bacteria Eukary a Archaea Early Earth and Origins of Life

20. Hypothesis: Going from Cenancestor to 3 Domains I. Prokaryotes oxygenate the atmosphere cellular metabolism evolved in prokaryotes first organisms are chemoheterotrophs no oxygen in atmosphere (so anaerobic) only food is organic matter in primordial soup

21. Hypothesis: Going from Cenancestor to 3 Domains I. Prokaryotes oxygenate the atmosphere second to evolve are simple autotrophs give off oxygen as by product this leads to the oxygenation of atmosphere some hypothesize that these were photosynthetic Cyanobacteria-like organisms third to evolve are heterotrophs that use oxygen (aerobic)

22. This is the Heterotroph Hypothesis: chemoheterotrophs > autotrophs > heterotrophs no O 2 present produce O 2 use O 2 Hypothesis: Going from Cenancestor to 3 Domains I. Prokaryotes oxygenate the atmosphere

23. Cytoplasm DNA Plasma membrane Ancestral prokaryote Infolding of plasma membrane Endoplasmic reticulum Nuclear envelope Nucleus Engulfing of aerobic heterotrophic prokaryote Cell with nucleus and endomembrane system Mitochondrion Ancestral heterotrophic eukaryote Plastid Mitochondrion Engulfing of photosynthetic prokaryote in some cells Ancestral Photosynthetic eukaryote How we got organelles- the hypothesis Hypothesis: Going from Cenancestor to 3 Domains II. Going from prokaryotes to eukaryotes

24. First, membrane in-folding created endoplasmic reticulum and nucleus

25. Hypothesis: Going from Cenancestor to 3 Domains II. Going from prokaryotes to eukaryotes second, endosymbiosis led to formation of mitochondria and chloroplasts Endosymbiotic Theory mitochondria from heterotrophic (aerobic) prokaryote chloroplasts from photosynthetic prokaryote (Cyanobacteria ?)

26. Modern evidence for Endosymbiotic Theory Mitochondria and chloroplasts are prokaryote- like