Evolution The Origins of Life I. Cellular Life

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.

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.

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

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

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

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

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

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

Organic Molecule Hypotheses Miller-Urey Experiment-Passed an electrical current through mixture of gases and created amino acids and nucleotides 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 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? Question: What do amino acids make?

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

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

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

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