Difference Between Abiogenesis and Spontaneous Generation

The key difference between abiogenesis and spontaneous generation is that abiogenesis is the theory that states all life started from inorganic molecules while spontaneous generation is the theory that states complex life arises spontaneously and continually from nonliving matter. 

Abiogenesis and spontaneous generation are two theories that attempt to describe how life on Earth has begun and living things originate. Both of these theories explain the emergence of life from non-living materials. Abiogenesis explains the generation of primitive organisms while spontaneous generation explains the generation of complex organisms.

CONTENTS

1. Overview and Key Difference
2. What is Abiogenesis 
3. What is Spontaneous Generation
4. Similarities Between Abiogenesis and Spontaneous Generation
5. Side by Side Comparison – Abiogenesis vs Spontaneous Generation in Tabular Form
6. Summary

What is Abiogenesis?

Abiogenesis is a theory that states the life on Earth arose from nonlife more than 3.5 billion years ago. It also states that the first life formed on Earth is very simple and primitive. Since abiogenesis states that life originated from nonlife, this theory is opposite to biogenesis. This theory was considered as evolutionary theory. Stanley Miller is one of the pioneers in developing abiogenesis theory.

According to abiogenesis, organic molecules are created by the forces or nonorganic sources. The synthesis of both proteins and RNA in the laboratory is proof of this fact. Abiogenesis argues that self-replicating molecules, together with other molecules, may have produced the basic structure of life, which is the cell. These self-replicating molecules were RNA molecules, and these RNA molecules were transformed into proteins or DNA due to mutations.

The Oparin-Haldane theory also claimed that organic molecules could be formed from abiogenic materials in the presence of an external energy source. Therefore, the ideas of Oparin-Haldane theory formed the foundation for much of the research on abiogenesis that took place in later decades.

What is Spontaneous Generation?

Spontaneous generation is an obsolete theory that states life can arise from nonliving matter. The Greek philosopher Aristotle first proposed this spontaneous generation theory. According to this theory, organisms do not descend from other organisms or from a parent. It only requires that certain conditions in their environment be fulfilled in order for creation to occur. Spontaneous generation explains the generation of complex organisms. Some examples are dust creating fleas, maggots arising from rotting meat, and bread or wheat left in a dark corner producing mice, etc.

Several scientists, including Francesco Redi, John Needham, Lazzaro Spallanzani, and Louis Pasteur, performed different experiments/research studies to disprove this theory. Francesco Redi showed that maggots arise from the eggs of flies rather than directly from rotting. Later, Louis Pasteur did experiments with flasks with twisted necks (swan-neck flasks) and proved sterilized broths in swan neck flasks remained sterile. Unless microbes are introducing from outside from air, the broths remained sterile, and there was no growth of microorganisms. Pasteur’s experiments disproved spontaneous generation theory by proving “life only comes from life”.

What are the Similarities Between Abiogenesis and Spontaneous Generation?

• Both abiogenesis and spontaneous generation state that living things originate from nonliving things.
• Both these theories are no longer used, so they are obsolete theories.

What is the Difference Between Abiogenesis and Spontaneous Generation?

Abiogenesis is a theory on the creation of organic molecules from inorganic sources while spontaneous generation is a theory on the creation of complex life from nonliving things. So, this is the key difference between abiogenesis and spontaneous generation. Moreover, abiogenesis theorizes that primitive life (self-replicating RNA and protein molecules, etc.) originated from nonliving matter while spontaneous generation theorizes on the generation of complex life (mice and maggots, etc.) from nonliving matter. Furthermore, abiogenesis has been neither proved nor disproved. But spontaneous generation theory was disproved.

Below is a summary of the difference between abiogenesis and spontaneous generation in tabular form.

Summary – Abiogenesis vs Spontaneous Generation

Abiogenesis and spontaneous generation are two theories that state living creatures could arise from nonliving matter. Therefore, both theories believe that non-living objects can give rise to living organisms. Abiogenesis mainly discusses the generation of primitive organisms, while spontaneous generation theory discusses the generation of complex organisms. Moreover, scientists have neither proved nor disproved abiogenesis. However, spontaneous generation has been disproved by several scientists. Thus, this summarizes the difference between abiogenesis and spontaneous generation.

Reference:

1. “Abiogenesis.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., Available here.
2. “Spontaneous Generation.” Lumen, Available here.

Image Courtesy:

1. “Miller-Urey experiment-en” By GYassineMrabetTalk✉  This W3C-unspecified vector image was created with Inkscape.iThe source code of this SVG is valid. – Own work from Image:MUexperiment.png (CC BY-SA 3.0) via Commons Wikimedia
2. “OSC Microbio 03 01 Rediexpt” By CNX OpenStax – (CC BY 4.0) via Commons Wikimedia