Different Experiments

by • 14/07/2011 • Old Pattern Biology NotesComments (0)576

REDI’S EXPERIMENT

Redi took four bottles. He put a dead snake in one bottle, a few dead fish in second bottle, dead eel in third bottle and a piece of meat in the fourth bottle. All these bottles were left open. The flies could enter these bottles. Then he took four more such bottles. He put some dead animals in all four bottles but covered the mouth of bottles.

(Figure from book)

After few days, maggots were produced in four open bottles. Maggots were not produced in closed bottles. Moreover, no flies were seen. Therefore, it was proved that maggots were not produced spontaneously by produced due to flied which were visiting the open bottles. The maggots were the larvae produced from the eggs of the visiting flies.

NEEDHAM’S EXPERIMENT

In 1948, an English scientist Needham boiled the meat in the water and prepared gravy. He poured this gravy into the bottles and closes their mouth with corks. After some days, many microscopic organisms were produced. In this way, the believers of abiogenesis were once again gain courage.

(Figure from book)

EXPERIMENT OF SPALLANZANI

In 1767, an Italian scientist Spallanzani criticized the experiment of Needham. He said that air entered the bottles through the pores of cork and hence living organisms were produced.

(Figure from Book)

Spallanzani put the boiled meat and vegetables in clean bottles and then sealed the mouth of bottles by heat. He placed these sealed bottles in boiled water to kill the possible germs. After some days, he found no organisms. He left the same boiled meat and vegetables in open bottles at the same time. Some living organisms were produced in these bottles. This supportd the concept of Biogenesis. But the believers of Abiogenesis said that air removed by Spallanzani was necessary for living things so no organisms were produced in sealed bottles. When oxygen was discovered the supporters of Abiogenesis said that Spallanzani had removed oxygen where by no life could be produced in his experiment.

EXPERIMENT OF LOUIS PASTEUR

The argument on Biogenesis and Abiogenesis continued up to the middle of, 19th century. A well-known French scientist, Louis Pasteur proved, after simple but very careful experiments, that abiogenesis could not occur in present environment of earth. He proved that living organisms could only be produced from their parents.

In 1864, Pasteur performed his experiment in front of the commission formed to solve the issue. He took flasks, which had long curved S-shaped necks. He placed fermentable infusion (Yeast + sugar + water) in flasks and left their mouth open.

(Figure from Book)

He boiled the yeast infusion in the flasks. After this, he allowed to cool them and kept them as such. He observed that no life ws produced even after the lapse of several days, because microscopic organisms entering along with air got stuck up in on the curved walls of the glass necks. Then he broke up the curved necks, so that air containing microscopic organisms could reach the infusion. Now he noted that microscopic organisms were produced within 48 hours. This proved that if care was taken and no microscopic organisms and reproductive structures (eggs or spores) approach the infusion, no life could be produced because thee is no spontaneous generation of life from non life. After Pasteur, no further experiments were performed on origin of life for the next 60 years. In 1920, a Russian biochemist Alexander Oparin and a British biologist J.B.S 1-Ialdane suggested that life on earth was originated after a long and gradual molecular evolution and there was no spontaneous and miraculous origin of life on earth.

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