Theory of Special Creation:

Life was created by God. According to Genesis of Bible, God created the world in six days in the following order:

(i) Heaven & Earth

(ii) Sky & water

ADVERTISEMENTS:

(iii) Land and land plants

(iv) Sun, moon & stars

(v) Birds and fishes

(vi) Land Animals and Humans

ADVERTISEMENTS:

The first man was Adam and the first woman Eve (takes out from ribs of Adam). Hindu mythology believes that the word was created by Brahma-gods, demons and humans from his head, birds from breast, goats from mouth, herbs, fruits & roots from hair. Hindu mythology also believes that there was a first man named Manu and the first woman named Sharadha. No scientific basis nor any evidences.

Theory of Spontaneous Generation/Abiogenesis (= Autobiogenesis)

It originated in Egyptian civilisation. Greek philosophers believed in it. Anaximander (611-547 BC) thought life to arise from mud warmed by sun. Aristotle (384-322 BC) believed plants to develop from soil while worms and snails to be product pertrefaction. Van Helmont (1577-1644) had claimed origin of mice of both sexes from human sweat and wheat bran kept in dark for 21 days.

Biogenesis:

ADVERTISEMENTS:

Theory of spontaneous generation was disapproved through that finding, the “life comes from pre-existing life (omme vivum evivo). Fransesco Redi (1668) placed thoroughly cooked meat in three jars:

(i) uncovered

(ii) covered with parchment

(iii) covered with muslin.

ADVERTISEMENTS:

Maggots developed only in the uncovered jar. No maggot developed in jar covered by parchment. Flies visited the third jar and laid eggs on the muslin. Eggs fallen in the jar produced maggots. Spallanzani (1965) boiled nutrition broth in glass flasks, sealed the flasks and kept them. The broth remained clear indefinitely with no signs of living beings.

Pasteur (1860, 1862, 1864) took broth in flasks having swan (bent S-shaped) necks, boiled and allowed the broth to cool. No germs developed in the broth through it can was connected with the atmosphere through curved necks of the flasks.

The dirt pastides could not reach the broth because they got trapped in the bend of the neck. When the swan necks were broken, broth developed colonies of microorganisms showing that the same have come from air. The theory of biogenesis is, however, not applicable to origin of life.

Cosmozoic/Interplanatery Theory (Theory of Panspermia):

ADVERTISEMENTS:

Primitive life or ‘Panspermia’ came to earth in the form of germs and spores from other heavenly bodies through meteorites (Richter, 1865, Arrhenius, 1908). Some of the meteorites are found to contain organic compounds, e.g. Orgenel meteorite in Paris, Murray meteorite in U.S.A. Murchison meteorite in Australia.

The latter has many left handed amino- acids. Possibility of living structures coming from other planets is remote became of high temperature and lethal radiations in the interstellar space.

Oparin-Haldane Theory/(Biochemical Origin of Life):

It is also called theory of ‘protobiogenesis’ (Fox and Dose, 1972). The theory was proposed by Russian scientist Alexander Ivanovich Oparin (Origin of Life, 1923), and British turned Indian Scientist J.B.S. Haldane (1928).