chapter 26 Early Earth & the Origin of Life


Chapter 26    Early Earth & the Origin of Life

Objectives

The Origin of Life
1. Describe the four stages of the hypothesis for the origin of life on Earth by chemical evolution.
2. Describe the contributions that A. I. Oparin, J.B.S. Haldane, and Stanley Miller made toward developing a model for the abiotic synthesis of organic molecules. Describe the conditions and locations where most of these chemical reactions probably occurred on Earth.
3. Describe the evidence that suggests that RNA was the first genetic material. Explain the significance of the discovery of ribozymes.
4. Describe how natural selection may have worked in an early RNA world.
5. Describe how natural selection may have favored the proliferation of stable protobionts with self-replicating, catalytic RNA.
   
  Introduction to the History of Life
6. Explain how the histories of Earth and life are inseparable.
7. Explain how index fossils can be used to determine the relative age of fossil-bearing rock strata. Explain how radiometric dating can be used to determine the absolute age of rock strata. Explain how magnetism can be used to date rock strata.
8. Describe the major events in Earth’s history from its origin until 2 billion years ago. In particular, note when Earth first formed, when life first evolved, and what forms of life existed in each eon.
9. Describe the mass extinctions of the Permian and Cretaceous periods. Discuss a hypothesis that accounts for each of these mass extinctions.
   
  The Major Lineages of Life
10. Describe how chemiosmotic ATP production may have arisen.
11. Describe the timing and significance of the evolution of oxygenic photosynthesis.
12. Explain the endosymbiotic theory for the evolution of the eukaryotic cell. Describe the evidence that supports this theory.
13. Explain how genetic annealing may have led to modern eukaryotic genomes.
14. Describe the timing of key events in the evolution of the first eukaryotes and later multicellular eukaryotes.
15. Explain how the snowball-Earth hypothesis explains why multicellular eukaryotes were so limited in size, diversity, and distribution until the late Proterozoic.
16. Describe the key evolutionary adaptations that arose as life colonized land.
17. Explain how continental drift explains Australia’s unique flora and fauna.
18. Explain why R. H. Whittaker’s five-kingdom system has been replaced by a new system with three domains.
   

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