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The Origins of Life: Evolution and Cellular Diversity

Explore the origins of life and the process of evolution through the study of natural selection, biological diversity, fossil evidence, and mass extinction. Analyze multiple sources of evidence to understand how life forms developed and the importance of species diversity in surviving environmental changes.

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The Origins of Life: Evolution and Cellular Diversity

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  1. Evolution The Origins of Life I. Cellular Life

  2. California Standards • BI. 8. a. Students know how natural selection determines the differential survival of groups of organisms. • BI. 8. b. Students know a great diversity of species increase the chance that at least some organisms will survive major changes in the environment • BI. 8. e Students know how to analyze fossil evidence with regard to biological diversity, episodic speciation, and mass extinction.

  3. Learning Objectives • SWBAT… • Explain how natural selection determines the differential survival of groups of organisms. • Analyze multiple sources of evidence for evolution. • Explain how a great diversity of species increase the chance that at least some organisms will survive major changes in the environment • Analyze fossil evidence with regard to biological diversity, episodic speciation, and mass extinction.

  4. Review-Questions About Our Origins • How did the universe form? • How did our galaxy form? • How did the sun and Earth form? • How/where did life start? • How did all the life forms on Earth develop? • Where do humans come from?

  5. Review-What evidence is there for evolution? • Fossils • Geologic • Age of the Earth • Anatomy and Physiology • Molecular (DNA, “primordial soup”)

  6. Review-What is evolution? • A changes in a species over time • process of biological change by which descendents come to differ from their ancestors.

  7. What explanations are there for how life started on Earth? • Christianity-God • Buddhism-no creator, world constantly recreates itself • Islam-Allah • Native Americans-mother, mother animals • Aztec-gods-5 births of suns • Bantu-Bumba vomitted up “life” and Planets

  8. Review-How was the Earth formed? • Our solar system (Sun and planets) formed from a rotating disk of gas and dust about 4.6 billion years ago. • 4-3.8 bya Earth cooled down and the impacts happened less • Solar radiation and lightning produced energy for reactions on Earth • Water vapor condensed and rain formed large bodies of water • Presence of water allowed inorganic compounds to form organic molecules

  9. Origins of Life • Organic molecule hypotheses-(Miller-Urey and Meteorite Hypothesis) • Early cell structures-(Iron-sulfide, lipid membrane) • RNA-early genetic material

  10. Organic Molecule Hypotheses • Miller-Urey Experiment-Passed an electrical current through mixture of gases and created amino acids and nucleotides • Meteorite Hypothesis-Meteorite that landed in Australia had 90 different amino acids, possible that aa were brought to Earth on meteorites • Question: What do amino acids make?

  11. Early Cell Structures Hypotheses • Iron-sulfide bubbles hypothesis-4 b.y.a, hot iron sulfide chimneys concentrated basic organic molecules in small space • Lipid membrane hypothesis-lipid molecules can form spheres around organic molecules • Question: What do lipids make up?

  12. RNA as Early Genetic Material • RNA can chop and copy itself w/out enzymes • Short chains of RNA can form from inorganic molecules

  13. Summary-Molecular Origins of Life • Molecules create the structures for life. • Organisms are made of molecules. • Under the right conditions, nonliving molecules such as gases, lipids, amino acids, and nucleic acids can naturally form the structures of life.

  14. Summary Questions • What some of the different beliefs that various religions have on how life started on Earth? • In your own words explain one of the biological hypotheses on how life started on Earth.

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