Imagine swimming in a cozy volcanic vent of searing heat. Ammonia and methane swirl like a cosmic bowl of soup. Steam rises from the water into the thick chemical atmosphere. Suddenly…krakaboom! A bolt of lightning strikes the tumultuous sky. The ammonia and methane combine just at the water’s surface, fed by the heat from below. And in that moment something new appears: an amino acid; a protein; a building block for life itself. According to scientific convention, that’s how it happened over 3.8 billion years ago here on Earth.
The Quest for Answers of Origin
Ever since Darwin sailed to the Galapagos and penned his first theories of evolution, scientists have been trying to discover the origins of life. Mankind has been trying to decipher this very thing long before Darwin ever hypothesized that human beings evolved- as all animals do- from organic compounds. But in recent years more evidence through evolving technology and dauntless research has provided science and mankind with some new answers about an old problem. If we did indeed evolve from simple compounds in a complex environment, how did it happen?
Scientists currently believe that the planet Earth formed some 4.5 billion years ago, long after the “Big Bang” created our universe from a singularity at the rounded base of the time-space continuum. Then, some time around 3.8 billion years ago, the first rock formations began to appear, and microorganisms known as archebacteria developed. Somewhere in that .7 billion years in between, life began as a result of a specific set of necessary elements, and random chance.
Beginnings of Biochemical Evolution
We know from science that the so-called “primordial soup” of our world was made up of lots of water on the surface, and great quantities of methane and ammonia in the atmosphere. Below the surface of the water, volcanoes were constantly erupting and creating underwater land masses that would eventually rise to the “surface”. Those volcanoes were also creating a lot of heat and steam. Add to this mixture a great storm of chemical activity in the skies of that primordial Earth. The movements of Earth, sky, and chemicals resulted in electrical storms of unbelievable proportion. Based on recent studies in microbiology, biochemistry, and chemical paleontology, scientists hypothesize that at some key point either electrical activity or a catalytic metallic ion created the last necessary scenario for the creation of amino acids.
Amino acids have long been heralded as the building blocks of life. They are the simplest forms of an organic compound. They are also proteins. From the successful building of protein comes the creation of DNA and RNA. Once DNA and RNA begin to build upon themselves, complex organic materials are created: living cells such as bacteria, and amoebas. By 3.5 billion years ago cyanobacteria had developed.
Around 2.2 billion years ago, photosynthetic bacteria had utilized enough chlorophyll and emitted enough “waste” to create an oxygen rich atmosphere. It was approximately 2 billion years ago when bacteria had developed into eukaryotes, the first complex living cells. Many of the ancient water-bearing bacterium can still be seen today in the fossilized mounds called stromatolites along beaches around the world. These stromatolites are among the pieces of evidence that scientists are using to help investigate the era of the primordial soup. At first, scientists did not realize that these mounds were in fact fossilized bacteria.
The Contribution of Bacteria
There are bacteria of all shapes, sizes, and conditions. Bacteria can thrive in just about any environmental condition from extreme heat to extreme cold. As a result, scientists have been exploring the Arctic and Antarctica for clues to Earth’s bacterial past. Bacteria fossils as well as young living bacteria have been found in these harsh places. Scientists have also found bacterial fossils in salt beds hidden miles below the Earth’s surface.
With the sedimentary layering of Earth over time, crystals are formed when moisture is trapped. The same principles of aged compaction that can turn coal into diamonds can turn water and salt deposits into crystals that preserve anything within or attached to them. Scientists discovered ancient Bacillum bacteria in salt crystals found in the New Mexico desert. Those same samples were revived and produced new spores after millions of years of imposed hibernation in salt crystal. The estimate for this particular sample is 256 million years old. The discovery brings us one step closer to studying the elements and events that spawned life on our world 4 billion years ago.
In the end, we may never know exactly what happened in that ammonia and methane filled world of chemical storms and volcanic heat. But with each day of new discoveries, technological advances in biochemistry, and dauntless scientific endeavor, we will learn more: more about our world; and more about ourselves.
Sources:
- Berg, Jeremy Mark, John L. Tymoczko, and Lubert Stryer. Biochemistry . 5th ed. New York: W.H. Freeman, 2002.
- Hawking, S. W.. A brief history of time: from the big bang to black holes. Toronto: Bantam Books, 1988.
- Monasterskey, Richard. “Origins Series”. Science News, March 7th 1999.
- Simpson, Sarah. “Origins Series”. Science News, January 9th 1999.
- Travis, John. “Origins Series”. Science News, April 17th 1999, and June 12th 1999.
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