One theory of the evolution of microorganisms on earth is the Microevolution. It is believed that single- celled organisms began to mutate and undergo gene alteration to form other organisms. This gene alteration and mutation occurred because of the action of certain chemicals and radiation substances in the environment. The environment in turn evolved as more microorganisms are created and are acted upon by their surroundings.
On the other hand, microorganisms also interacted with the environment to allow this to happen. Every existing living being on earth has a role in the delicate balance of nature.
Even the cockroaches have a role to fulfill: to pollinate flowers and to eat debris, thereby lessening trash.
This goes true with microorganisms also.
Microorganisms are very small life forms which could only be viewed through a microscope. They could be generally classified into bacteria, viruses, archaeans, algae, protozoans and fungi.
These microorganisms are believed to take active part in the earth’s evolution through the following specific processes:
1. Specific strains exist for each bacterium. New strain occurs when DNA fragments are inserted or deleted due to the action of other microorganisms and chemicals. When this happens new strains are formed which could interact with their surroundings. New products are formed which may alter the existing earth environment.
2. Cloning occurs when microorganisms come from one parent microbe but are somehow altered due to characteristic and response of the host. These clones are sometimes more virulent than the original ones.
i.e. new strains of AIDs are infecting
new animal hosts which affect the survival of animals. Animals take active part in the earth’s evolution by altering their habitat according to their needs; just like how the earth’s environment is different during the dinosaur’s era.
3. Certain anaerobic microbes like Archaea consume methane thereby taking active part in the methane and carbon cycle in the earth’s atmosphere. The reduction of methane also reduces the earth’s temperature. If the earth’s temperature changes drastically, then the earth will further evolve to cope up with this change. In fact, it is believed that it is because of this species that more life forms thrived because of their unique properties.
4. Contrary to common belief that oxygen only comes from trees, certain bacteria called Cyanobacteria produce oxygen as their by product. This production of oxygen which is a basic air requirement for most living organisms had at one time caused the earth to evolve into a more conducive habitat.
5. The Nitrosospira species are bacteria that oxidize ammonia and contribute to the nitrogen content of soils. Nitrogen supports life forms as it is one major element of life. They are very important therefore in sustaining life in plants and animals. If plants and animals become extinct, then the earth will evolve into another era once more.
6. Many bacteria take active part in decomposing their environment. Examples are the Bacillus which tend to destroy their environment by decomposing it.
Imagine if these bacteria are present in humongous concentrations, then perhaps all flora and fauna would disappear and would create a new earth.
7. Toxins are substances produced by bacteria which affect other earth forms. The mortality caused by these substances has a significant effect on the earth’s biota. This would eventually lead to another evolutionary stage.
8. All bacteria react with their surroundings, either giving off beneficial or toxic substances. These would lead to a vital change in the soil, atmosphere or water.
When these three are affected, then this will effect a new era of evolution.
If we do not curb our wanton destruction of nature and our environment, (tree cutting, pollution, etc) then we ourselves would be the organisms who would cause the annihilation of all life forms here on earth. Perhaps, a new earth would evolve, back to the time that only the unicellular life forms existed!