This chapter define radiometric dating, serial endosymbiosis, Pangaea, snowball Earth, exaptation, heterochrony, and paedomorphosis; describe the contributions made by Oparin, Haldane, Miller, and Urey toward understanding the origin of organic molecules; explain why RNA, not DNA, was likely the first genetic material. | List 3 pieces of evidence to support the endosymbiont theory. The half-life of carbon-14 is about 5600 years. A fossil with ¼ the normal proportion of C14 is probably _ years old. Answer the following using the diagram below: a common ancestor for D & F most closely related species least related species new species C arises at this point common ancestor for E & F B C D E F 3 4 2 1 5 A Chapter 25 The History of Life on Earth What you need to know: A scientific hypothesis about the origin of life on Earth. The age of the Earth and when prokaryotic and eukaryotic life emerged. Characteristics of the early planet and its atmosphere. How Miller & Urey tested the Oparin-Haldane hypothesis and what they learned. Methods used to date fossils and rocks and how fossil evidence contributes to our understanding of changes in life on Earth. Evidence for endosymbiosis. How continental drift can explain the current distribution of species. How extinction events open habitats that may result in adaptive radiation. Early conditions on Earth Discovery Video: Early Life Earth = billion years old First life forms appeared ~ billion years ago How did life arise? Small organic molecules were synthesized Small molecules macromolecules (proteins, nucleic acids) Packaged into protocells (membrane-containing droplets) Self-replicating molecules allow for inheritance “RNA World”: 1st genetic material most likely RNA First catalysts = ribozymes (RNA) Synthesis of Organic Compounds on Early Earth Oparin & Haldane: Early atmosphere = H2O vapor, N2, CO2, H2, H2S methane, ammonia Energy = lightning & UV radiation Conditions favored synthesis of organic compounds - a “primitive soup” Miller & Urey: Tested Oparin-Haldane hypothesis Simulated conditions in lab Produced amino acids Protocells & Self-Replicating RNA Sedimentary rock (layers called strata) Mineralized (hard body structures) Organic – rare in fossils but found in amber, frozen, tar pits Incomplete record – many organisms | List 3 pieces of evidence to support the endosymbiont theory. The half-life of carbon-14 is about 5600 years. A fossil with ¼ the normal proportion of C14 is probably _ years old. Answer the following using the diagram below: a common ancestor for D & F most closely related species least related species new species C arises at this point common ancestor for E & F B C D E F 3 4 2 1 5 A Chapter 25 The History of Life on Earth What you need to know: A scientific hypothesis about the origin of life on Earth. The age of the Earth and when prokaryotic and eukaryotic life emerged. Characteristics of the early planet and its atmosphere. How Miller & Urey tested the Oparin-Haldane hypothesis and what they learned. Methods used to date fossils and rocks and how fossil evidence contributes to our understanding of changes in life on Earth. Evidence for endosymbiosis. How continental drift can explain the current distribution of species. How extinction events open habitats that may result in
