Biology The Origin of Life-Questions and Answers Graded A+

Biology The Origin of Life-Questions and Answers Graded A+ Life on earth date of origin - ANSWER-between 3.5 and 4 billion years ago Fist living creatures - ANSWER-Prokariotic-like; supported by the fossil record Spontaneous generation (definition) - ANSWER-The origin hypothesis where organisms come to life directly from non-living matter Spontaneous generation (origin) - ANSWER-Origin hypothesis created by Greek philosophers; Aristotle believed that life arose from "slime". Dis-proven by Louis Pasteur with meat in 1861. Inorganic model of life origin (Definition) - ANSWER-Origin of life hypothesis where complex organic molecules arose slowly from pre-existing, non-organic and self-replicating silicate crystals in solution Inorganic model of life origin (Experimental Evidence) - ANSWER-Able to produce polymers from dilute solutions of monomers by dripping the solution into hot sand, clay or rock. -Evidence has largely been inconclusive so far. Inorganic model of life origin (Key minerals) - ANSWER-Clay played an important role because monomers bind to the clay and concentrate. Pyrite (FeS2) also important because of its formation in sulfide-rich marine sediments and in high temperature anaerobic conditions where it could reduce CO2 to organic compounds. Panspermia hypothesis - ANSWER-Origin hypothesis where the first organic compounds reached our planet from meteorites and comets that collided with Earth during the Precambrian period Biochemical Model - ANSWER-Origin hypothesis where life is produced through a series of organic chemical reactions to form more complex biomolecules from simpler organic forms. First proposed in the 1920's by Oparin and Haldane. Hydrothermal Vent Hypothesis - ANSWER-Life originated around the hydrothermal vents last universal common ancestor (LUCA) - ANSWER-hyperthermophile single cell organism evolved in hydrothermal vents Dificulties in proving the biochemical Hypothesis - ANSWER-around the origins of life there was: -No or very little atmospheric oxygen -Intense energy provided by UV radiation, meteorite collisions, volcanic activity and lighting. -The first living organisms were the products of abiotic biochemical evolution. stage 1 of biochemical evolution - ANSWER-Abiotic synthesis and accumulation of small organic molecules. stage 2 of biochemical evolution - ANSWER-Joining of these building blocks into polymers (i.e. amino acids and proteins) stage 3 of biochemical evolution - ANSWER-Formation of droplets (protobionts) from aggregates of abiotically produced molecules