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Early Earth: From Origin to Evolution

Explore the age of Earth, emergence of life, Miller and Urey experiment, fossil dating methods, endosymbiosis evidence, and how continental drift shapes species distribution. Delve into the ancient history of life, from prokaryotes to eukaryotic organisms. Learn about the Origin of Life Hypothesis, organic monomers/polymer synthesis, molecular packaging, genetic replication, and the major lineages of life that have evolved over billions of years.

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Early Earth: From Origin to Evolution

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  1. Lecture #12 Date _______ • Chapter 25 ~ Early Earth and The Origin of Life

  2. You Must Knows • The age of the Earth and when prokaryotic and eukaryotic life emerged. • Characteristics of the early planet and its atmosphere. • How Miller and Urey tested the Oparin-Haldane hypothesis and what they learned.

  3. You Must Knows • Methods used to date fossils and rocks. • Evidence for endosymbiosis. • How continental drift can explain the current distribution of species.

  4. Early history of life • Solar system~ 12 billion years ago (bya) • Earth~ 4.5 bya • Life~ 3.5 to 4.0 bya • Prokaryotes~ 3.5 to 2.0 bya stromatolites • Oxygen accumulation~ 2.7 bya photosynthetic cyanobacteria • Eukaryotic life~ 2.1 bya • Muticelluar eukaryotes~ 1.2 bya • Animal diversity~ 543 mya • Land colonization~ 500 mya

  5. The Origin of Life • Spontaneous generation vs. biogenesis (Pasteur) • The 4-stage Origin of life Hypothesis: • 1- Abiotic synthesis of organic monomers • 2- Polymer formation • 3- Origin of Self-replicating molecules • 4- Molecule packaging (“protobionts”)

  6. Organic monomers/polymer synthesis • Oparin (Rus.)/Haldane (G.B.) hypothesis (primitive earth): volcanic vapors (reducing atmosphere) with lightning & UV radiation enhances complex molecule formation (no O2) • Miller/Urey experiment: • water, hydrogen, methane, ammonia • all 20 amino acids, nitrogen bases, & ATP formed • Fox proteinoid formation (abiotic polypeptides) from organic monomers dripped on hot sand, clay or rock • Oparin (coacervates) protobionts (aggregate macromolecules; abiotic) surrounded by a shell of H2O molecules coated by a protein membrane

  7. Abiotic genetic replication • First genetic material • Abiotic production of ribonucleotides • Ribozymes (RNA catalysts) • RNA “cooperation” • Formation of short polypeptides (replication enzyme?) • RNA~ DNA template?

  8. The Major Lineages of Life

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