GENBIO: Theories about the Origins of Life

• Divine Creation Theory. The theory of special creation proposes that life on earth is created by a supernatural power, the GOD. According to Christian belief, God created the universe, planets, animals, plants, and humans in six natural days. Similar beliefs are also been proposed by other religions as well.
• There are beliefs in the theory of special creation. These points are as follows: A. All living organisms were created on the same day. [No difference in their appearance]. B. They were created in the present form. [No evolution]. C. Their bodies and organs are fully developed to meet the requirements to run life. [No adaptation]
• OBJECTIONS TO THE THEORY OF SPECIAL CREATION: • It was purely based on religious belief. • There was no experimental evidence to support the assumptions. • The age of different fossils proves that living organisms appear on Earth in different time frames
• Abiogenesis Theory (Spontaneous Generation Theory). The theory of spontaneous generation or abiogenesis assumes that non-living material in a spontaneous manner gives rise to life.
• Biogenesis Theory. Lazzaro Spallanzani, Francisco Redi, and Louis Pasteur performed well-designed scientific experiments to disprove the theory of spontaneous generations.
• According to this theory (biogenesis theory), life can arise from pre-existing living things.
• Francesco Redi


  Did not believe that life originated from non-living matter
• Redi's experiment

  1. 3 jars with meat inside: uncovered, covered with gauze, and covered

  2. Jar no.1 had flies and maggots

  3. Jar no.2 had flies and maggots in the gauze

  4. Jar no.3 had no presence of flies and maggots
• From the experiment, especially in jar no.3

  Redi suggested that life did not originate from non-living matter (meat), but instead from a living matter like the flies who laid eggs which eventually turned to maggots
• Lazarro Spallanzani


  He constructed his experiment by placing broth in each of the two separate bottles
• Spallanzani's experiment

  1. Placed broth in 2 separate bottles

  2. Boiled the broth in both bottles for a long period at a high temperature

  3. Sealed one bottle and left the other bottle open
• Unsealed bottle


  Presence of microbial growth because it was exposed
• Sealed bottle

  No sign of any microbial growth
• Longer heating period and high temperature boiling had killed all microorganisms
• In the absence of microorganisms, life could not appear like what happened in the sealed bottle on his experiment
• Loius Pasteur

  Scientist who conducted an experiment with a swan neck flask
• Pasteur's experiment

  1. Boiled a nutrient-rich broth inside the flask

  2. Observed no life in it for one year

  3. Broke off the top of the bottle, exposing it more directly to the air

  4. Noted life forms in the broth within days
• Swan neck flask

  • Trapped dust and other airborne particles in the S-shaped neck
  • As long as this obstacle was present, no life was created
  • Once this obstacle was removed, life forms appeared in the broth
• Pasteur was convinced that even when exposed to air, life did not arise from non-life
• Pasteur believed that life came from pre-existing life
• The life forms found in the broth after it was opened came from the living matter found in the air
• Theory of Catastrophism: This is the extension of the theory of special creation. This theory assumes that life originated by creation and is followed by catastrophe due to geographical disturbances. Each catastrophe destroyed life completely, whereas each creation forms life differently from the previous one. Hence, each round of catastrophe/creation is responsible for the evolvement of different types of organisms on Earth. The criticism of the current theory is the same as the previous one. No scientific experiment to support the hypothesis and most are based on imaginary concepts.
• Theory of Cosmozoic

  Theory that life was present in the form of resistant spores and appeared on Earth from another planet
• Theory of Cosmozoic

  • Proposed by Richter and strongly supported by Arrhenius
  • Assumes that since the condition of the Earth was supporting life, these spores grew and evolved into different organisms
  • Also known as the "Theory of Panspermia or Apore Theory"
• Evidence for Theory of Cosmozoic

  • Fossils of microorganisms were found in meteorites in 1961
• Theory of Eternity of Life: This theory assumes that life has no beginning or end. It believes that life has always existed and will continue to be so. It further believes that there is no question of the origin of life as it has no beginning or end. The theory is also known as Steady State Theory. The main objection against this theory is that it could not explain evidence supporting the formation of Earth, and then life appeared on it.