Chapter 14 Beginning Of Life

Chapter 14 Beginning of Life I. Origin of life A. Abiogenesis or spontaneous generation: organisms arise from non-living things. B. Biogenesis: life comes from other living things. II. Scientists – abiogenesis VS biogenesis A. Redi: biogenesis 1. Raw meat and flies B. Needham: abiogenesis 1. Boiled vegies and/or meat broths and let contents stand in flasks (cork loose). 2. Organisms squeezed in; turned cloudy C. Spallanzini: biogenesis 1. Repeated Needham’s experiment a. Boiled in sealed glass b. No spontanious generated in sealed jar D. Pasteur: biogenesis 1. Proved microorganisms are present in dust particles. a. Swan necked experiment. III. The Early Earth and its Formation A. Earth formed 4.5 billion years ago 1. Cloud of gas and dust B. Earths matter cooled forming crust and core. C. Volcanic activity formed rain that fell creating oceans. D. Ancient seas were called Primordial Soup.

IV. Formation of Simple Organic Compounds A. Oparin: first scientist to suggest the ancient atmosphere 1. Gasses: a. Ammonia NH3 b. Hydrogen H2 c. Water vapor H2O d. Methane CH4 2. Chemical reactions = protein formation a. Primordial soup B. Urey & Miller: used Parin’s hypothesis 1. Used early gases and an electrical charge as a source of energy. 2. Result: compounds like amino acids formed. a. The electrical charge went back was lightning. V. Formation of Complex Organic Compound A. Complex organic compound. up together = protocell.

Formed when amino acids linked

VI. Concentration and Enclosure of Organic Compounds A. 1st cell like forms to arise. B. 2 types of droplets 1. Coacervates: collections of droplets made of different types of molecules. 2. Microspheres: round droplets made of only one molecule type. Proteins form a membrane. C. Characteristics of cells, coacervates, and microspheres, have in common: 1. All have membrane like boundaries.

2. Can selectively absorb substances from their surroundings. D. DNA somehow formed and became enclosed within the droplets from RNA. 1. A safe haven to carry out their precise reactions. VII.First Organisms A. Prokaryotes: first to appear on earth 1. Anaerobic (no H2O) 2. Found in primordial seas 3. Heterotrophic 4. Became autotrophic 5. Then photosynthetic prokaryotes evolved called blue-green bacteria or cyanobacteria released oxygen. B. Eukaryotes: have membrane bound organelles 1. Evolved from one or more prokaryotes coming together, one inside the other. a. Close association = symbiosis 2. Organelles then arose a. Endosymbiosis: •

Mitochondria – from ancient bacteria

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Chloroplasts – from cyanobacteria