Question

The main concepts of two theories regarding the origin of life on earth are given.

Answer 1

Different theories were given to explain the origin of life.

• Theory of special creation:

According to this theory, god created life by his divine act of creation.

• Theory of panspermia /cosmic theory:

According to early Greek thinkers, units of life called spores or panspermia came from outer space and developed into living forms.

• Theory of spontaneous generation:

According to this theory, life originated from decaying and rotting matter like straw, mud, etc.

Louis Pasteur: Dismissed the theory of spontaneous generation and demonstrated  that life came from pre-existing life.

He placed a killed yeast in pre-sterillised flask and another open to air.He showed that life did not originate in the former but new living organisms arose in the latter flask.