Russian biochemist A.I. Oparin and an English biologist J.B.S. Haldane gave the widely accepted theory on origin of life.

[Theory of Biochemical origin of Life or Modern Theory on Origin of Life or Oparine-Haldane theory all are same]

In the beginning, the primitive seawater was quite hot and full of simple organic compound like amino acids, nitrogen bases, simple sugar etc. which is named as primordial soup.

Life was originated on primitive sea water of earth under following peculiar conditions:

• Reducing type atmosphere,
• High heat energy due to the recently formed earth and frequent volcanic eruption,
• High intensity of light due to Frequent lightening,
• Presence of UV rays as the ozone layer was not developed

According to Oparine's concept, origin of life in the beginning is due to the biochemical process occurred in the primitive sea water. The simplest organic compound such as amino acid, nucleic acid were formed first and later in the presence of energy these compounds reacted vigorously to give rise to the first form of life. Then slowly evolved into distinct prokaryotes, eukaryotes and higher organism.

Protobiont or eobiont is the first form of life originated in the primitive sea water.

[Cocervates can show some basic living property so they are considered to be the foundation of life. First form of life is protobiont that comes after the changes in coacervates and acted like as a cell like creature so considered as first form of life]

Coacervate is a mixture of different biomolecules of primitive seawater as an organized colloidal system which could absorb nutrient and can replicate like a simple living creature.