-
The creation
The creation myth is the basis of religions. The religious texts (Bible...) describe a Genesis that tells the origin of the world, the living things and the human species. The creations are made by some creator, god or spirit that acts over matter... In the West these stories were accepted. In 1650, James Ussher calculated that God created the world in 4004 B.C. -
Spontaneous generation
In ancient Greece, people was believed that life appeared spontaneously when the conditions were appropriate. Aristotle made the great synthesis of spontaneous generation. He believed that the living beings could be generated by the organic matter in decomposition. The generation theory survived during for two thousand years until Francesco Redi and Lazzaro Spallanzani did an experiment in the seventeenth century. -
Redi's experiment
In 1665, Francesco Redi put pieces of meat and fish in various containers. One container covered with a very fine muslin and other containers uncovered. After several days, he noted that only grew maggots on meat and fish in the open bottles. This showed that the worms don't appear of nowhere.
http://phschool.com/atschool/phsciexp/active_art/redi_pasteur_experiment/redi_pasteur_experiment.swf -
Louis Pasteur's experiment
The theory of spontaneous generation was eliminated in the nineteenth century, when the Paris Academy of Sciences gave a prize for the person that refuted or demonstrated the theory of spontaneous generation. Louis Pasteur demonstrated that there wasn't spontaneous generation because living beings come only from other living beings predecessor. Also, they are responsible for the decomposition of matter. -
Pasteur's experiment
Pasteur prepared a nutrient broth. He placed amounts of the broth into a long-necked flask. He bent to form an "S" shape. Then he boiled the broth to kill any living matter in the liquid. After several weeks, Pasteur observed that in the curved-neck flask had not changed. The flask trapped germs in the curved neck. Pasteur argued that the germs could only come from other germs.
http://phschool.com/atschool/phsciexp/active_art/redi_pasteur_experiment/redi_pasteur_experiment.swf -
Panspermia: the cosmic origin of life
Richter began to develop the idea that the Earth was impregnated by microorganisms from space. In 1906, Svante Arrhenius Richter returned to the idea of the theory of panspermia. The theory of panspermia is the hypothesis that life came to Earth in the form of bacterial spores, because life exists throughout the Universe, distributed by meteoroids, asteroids, comets and planetoids. This theory doesn't explain how life formed in the hypothetical planet. -
Oparin's theory
In 1924, Oparin proposed that the chemical compounds that existed in the primitive atmosphere served for the synthesis of the most simples living beings. The first living systems have appeared after a long prebiotic evolution. Oparin suggested that the infant Earth had possessed methane, ammonia, hydrogen and water vapor. In Oparin's formulation, there were first only simple solutions of organic matter, but the interactions of these molecules formed the molecules more complex. -
Miller's experiment
In 1953, Stanley Miller demonstrated the first stages of the theory of Oparin. Miller introduced boiling water with a mixture of gases into a container. This mixture of gases formed the primitive atmosphere (methane, ammonia and hydrogen). Miller used electrodes through the mixture during a week. When the mixture cooled and Miller analyzed the contents of the container, he was found that in the mixture have been synthesized various simple organic compounds (amino acids).
