Biogenesis

Biogenesis is an important theory in biology as well as molecular genetics. Basically, it postulates the production of new living organisms from pre-existing life. The term Biogenesis refers to “Life from Life”. Also, it refers to any process like a lifeform that can give rise to other lifeforms.

Biogenesis comes from ‘bio’  which means life and ‘genesis’ which means beginning. So, we can elaborate as life can only emerge from living organisms.

History

Most scientists were skeptical of the spontaneous generation hypothesis, mainly in later decades. In 1858, Rudolf Virchow thought about the hypothesis of biogenesis, but he did not have any experiments to back it up. After that in 1859, Louis Pasteur set up his demonstrative experiments to prove biogenesis at a bacterial level of study. By 1861, finally, he succeeded in establishing Biogenesis as a solid theory rather than a controversial hypothesis. He solved this problem by setting up his own experiments to test.

Biogenesis

The theory of biogenesis states that new living organisms can only emerge from other previously existing living organisms as a result of reproduction. Basically, reproduction can occur sexually or asexually, so life can only arise from living cells.

Example  

Basically sexual and asexual reproduction are examples of biogenesis. The organisms that receive half their genetic material from two parent cells refer to sexual reproduction. And the other side, asexual reproduction refers to the organisms that receive all their biogenetic material from one single parent cell. 

Spontaneous Generation vs Biogenesis

At that time some experiments were conducted by different scientists to disprove the theory of spontaneous generation.

Experiment no. 1

An Italian physician disproved the idea of spontaneous and also proved the flies arose from the living and existing flies.

Procedure

• Selected two large & clean glass beakers.
• The same amount of meat was placed into the beaker.
• Kept open the first beaker.
• The second beaker was covered or closed with the lid.
• Placed the two beakers aside and left them undisturbed for a few days.

Observation

After some days, he observed that:

• In the first beaker without a lid, many of maggots developed on meat, and flies were present in and around it.
• In the second beaker which with a lid, there were neither maggots nor flies around it.

Final Result

• The whole experiment disproved the idea of spontaneous generation for all living organisms, from smaller microbes to giant animals as well.

Experiment no. 2

A French biologist, microbiologist, and chemist named Louis Pasteur are remembered for his remarkable experiments and descriptions. Also, he gave the Theory of Biogenesis.

If we mention his experiments, he proved that microbes come from other microbes. According to Pasteur’s hypothesis: All living organisms arise from the cells of organisms on the dust particles in the air, not from the air itself.

Procedure

• By selecting multiple unique S-shaped flasks and divided them into two different sets & prepared a broth.
• Added the prepared broth to the first set of S-shaped flasks then boiled it, and sealed the flasks with lids. 
• Added the prepared broth to the second S-shaped flask then boiled it and uncovered it.
• After that, he placed both flasks (first and second) sets at different locations.

Observation

After some days, he observed that:

• The dust collected on the neck of the flasks.
• In the first set of flasks, there was nothing of microbial growth.
• In the second set of flasks, there was microbial growth as well.

Final Result

So, he proved that microbes are also present in the air but will not arise from the air or dust. In both sets of flasks, he used to boil broth the same, but the first set of flasks was sealed and the second set was left open for microbes to enter, reproduce and multiply.

Experiment no. 3

Lazzaro Spallanzani was an Italian Catholic priest, biologist, and physiologist who designed an experiment in which broth was boiled for some minutes(45 min) in a flask that was under a slight vacuum and after that fused the top of the flask to seal out both air and germs. 

It’s like: Abiogenesis to Spontaneous Generation to Life could come from non-living things

Procedure

• Took two bottles and broth(liquid medium containing proteins and other nutrients) in each of the two separate bottles
• In the first bottle, heat the broth and cool it after some time. Then open the flask and wait.
• In the second bottle, heat the broth and sealed the flask, and wait.

Observation

After waiting some time, he observed that:

• In the first part, there had some growth and got some living organisms like microbes.
• In the second part, basically, there had no growth. So, open the flask and the microorganisms grew.

Final Result

Lazzaro Spallanzani concluded that while one hour of boiling would sterilize the soup, a few minutes of boiling was not enough to kill any present bacteria. Also, the microorganisms in the flasks of spoiled soup had entered the air.

FAQs on Biogenesis

Question 1: What are the strengths of biogenesis?

Answer: 

The theory of biogenesis explains that living organisms came from other living organisms, as opposed to the theory of spontaneous generation which say that living things came from nonliving matter. So, it is well supported by other investigations.

Question 2: Which is more accepted biogenesis or abiogenesis?

Answer: 

The difference between abiogenesis and biogenesis is that abiogenesis has not been approved by scientific experiments whereas biogenesis has been proved by scientific experiments. So, biogenesis is more accepted.

Question 3: What are the main arguments for biogenesis?

Answer: 

The theory of biogenesis states that new living organisms can only emerge from other previously existing living organisms as the result of reproduction.

Question 4: What is membrane biogenesis?

Answer: 

Membrane biogenesis is the process of formation of the biological membrane. It involves the synthesis of cell membranes with the help of proteins and lipids.

Question 5: How is biogenesis related to cell theory?

Answer: 

The idea of spontaneous generation was replaced by cell theory which states all cells come from the existing cells, not from non-living things. This process is also called biogenesis.