Life and its Origin

Most of the ideas on the origin of life fall into either of the following four theories:

Theory of Special Creation:
Theory of Special Creation was proposed by Spanish monk, Father Sauraz. This theory assumes that life was created by some supernatural power, beyond the analytic capacity of physics and chemistry. According to Christianity the Bible states that the creator formed all the living organisms with in six natural days. Materia prima on first day, plants on third day, fish and fowl on fifth day and animals including man on sixth day. According to Hindu mythology Brahma created various forms of life on one stroke. Manu and Shradha were the first man and woman on the earth.

Cosmozoic Theory or Theory of Panspermia:
Origin of life according to Cosmozoic Theory is proposed by Richter and Arrhenius. The life in the form of resident spores called panspermia reached this earth accidentally from other planets and developed into organisms.

Theory of Abiogenesis (Spontaneous Generation):
Von Helmont proposed that life in the form of simple organisms originated spontaneously from the non-living substances. Anaximander proposed that the air as sole cause of life. Von Helmont proposed that mice will be developed when human sweat and wheat are kept together for 21 days. Like wise insects from dew, butterflies from the cheese and maggots from the decaying meat.

Theory of Biogenesis:
The origin of life according to this theory is proposed by Francesco Redi (1621-1674) provided major set back to the Theory of Abiogenesis. On the basis of the experiments, Redi concluded that flies arise only from the eggs laid down by the parents flies, i.e, life can arise only from pre-existing life. Louis Pasteur (1864) also supported this theory of biogenesis.