Abiogenesis and Other Concepts: Tracing the Origin of Living Organisms on Earth
Take a Moment
When you look around, the butterflies, flowers, lovely people taking care of you, the buzzing honeybees, the cool shadows of the big trees make you feel awesome. There is a splendid richness in our lives because of these living things around us. That is life! The bliss of being alive is an amazing experience. Life on earth exists from 76 km above the surface to 19 km down the earth. Most of it is comprising of unknown microbial life. While you think for a moment, you may wonder what, where, how, when did all these have come into existence. The mystery is only for you to question and find the answer.
Life is full of surprises and questions, the origin of LIFE itself is a big mystery. I'm here trying to describe the most discussed, possible explanations for the origin of life on our planet.
Humans are curious about nature. We tend to find a reason for everything from childhood. This curiosity made humans go to the moon and far beyond the stars with our imagination.
Let’s start with defining life itself. “Life includes some fundamental processes essential for survival, reproduction, continuing to change, using energy to sustain, lastly death” at least to our knowledge we define this as life.
The Quest of Life is Continuing
How does life start on earth? What is the starting point of life? Are we created by someone? If created who was our creator? How do all living forms originate?
There are many theories, assumptions, hypotheses, experiments, debates, etc. all over the world from some of the greatest brains for many centuries to address those questions. This analytical ability is what sets us apart from the animal kingdom.
Officially the first evidence of life found on the old geysers near Australia around 3.77 billion years ago. This was the combined effort of molecular biologists, paleontologists, astrobiologists, biophysicists, geochemists, biochemists. These people were concerned with the study of life at its very beginning.
With the combined knowledge over the decades, we have some rough estimates about the genesis of life, it has 2 possible ideas we are either born here or we are planted by someone here. I'm here trying to give a piece of basic knowledge to both of these ideas.
Our Precious Planet-Earth
Earth is the only place known to us which supports life in the entire universe.
- Our home planet has formed around 4.5 billion years ago.
- Oceans are known to be formed around 4.4 billion years ago.
- Solid crust(Eoarchean land) formed 3.48 billion years ago.
Important Molecules of Life
Let us assume life formed here on earth, according to our basic understandings of laws of nature we can say that there are some essential entities to life.
- Atmospheric conditions
Carbon is the common and major constituent for the biomolecules like lipids (cell walls), carbohydrates (sugar and cellulose), amino acids(proteins) nucleic acids (RNA and DNA). Every living being has carbon as a major element in their DNA molecules.
If this theory was true life must have originated here right, beneath our foot. The hypothesis is that life arranged itself from complex molecules available, in the deep oceans. This is the most accepted theory of this domain, assuming we don’t give that credit to god.
This is a very complex concept because just think of a bucket of water(assume that it doesn't contain anything except water) in your home as the early earth and by somehow a microbial life emerges and as the time progresses the diversity has begun and that microbe is now a fish and that fish comes out of the water to the land and evolves into all the living creatures we know. There are certain possible ways that this process can happen. Let's have a look at them.
The most profound argument about early life forms on earth is that it formed near the volcanic vents under the seawater. The heat, the temperatures, and some compounds that have contributed to manifesting the earliest unicellular organisms.
Prokaryotes—the first life on earth fed on carbon compounds. Its cyanobacteria meaning that these little creatures won't have organelles(tiny structures inside the cell which carry out specific functions essential for survival) and there’ll be no distinct nucleus, the genetic material mixes with the rest of the cell.
This theory is most likely because we all know water is the basic building block of every living thing, and water itself must have created us.
Are you familiar with the word geothermal vents?
RNA Based Life
The fact that RNA is more short-lived and random mutating nature of it, has grabbed the attention of scientists to relate to our topic. Life would have originated during a random event in some of the complex molecules and it has sustained, due to the formation of RNA.
Theoretically, One tablespoon of DNA can store all worlds data ever produced
Thunders and Lightnings
One more alternative is that thunders are a very energetic phenomenon in nature. This enormous amount of energy produced can be the triggering point of life. Complex biomolecules might've just got the suitable for getting organized themselves into life. To support this theory in the 1952 Miller-Uray experiment had concluded that most of the amino acids, proteins in all living organisms can be synthesized inorganic compounds under specific conditions that replicate those of ancient earth.
Interesting Experiment by Haldane and Oparin
These two Russian scientists have done interesting work in addressing this question. Surprisingly, They have found that atmospheric oxygen prevents the synthesis of organic molecules, organic molecules are building blocks of life.
Oparin further argued that “primordial soup” (the concept that every creature originated from a single ancestor) of organic material is formed without oxygen or with the use of very little oxygen. This would urge each of these molecules to get closer and closer thereby forming even more complex molecules called “droplets”.These droplets would grow and reproduce through fusion to produce daughter droplets. And so they have a primitive metabolism in which those factors promote “cell integrity”, and those that do not become extinct moreover that’s the starting point.
One of the possible explanations for this can be that life on earth doesn’t start on earth. It stared elsewhere in the universe and came here by some means of transport. Life on earth could be one seed out of many existing civilizations all around the universe.
This theory was proposed by Arrhenius and supported by Fred Hoyle. This goes like this “Life existing already in parts of our vast universe got here through asteroids, comets, where the tiniest living cells got accumulated on those interstellar objects like dust accumulates on vehicles while traveling".This has a chance to happen when the planet-hosting life was being hit other asteroid and gets ejected into vast space in all possible directions. This theory is now got an extension that alien space crafts with contaminated microorganisms have accidentally arrived at baby earth some 3.7 billion years ago. If this prediction was right we have much more complex questions to answer later on.
The reason for this can be true is the fact that when objects are further away from the star, the heat energy will they receive reduces significantly. This is only a bit of common sense. If microbial life gets trapped in some of these space objects they can travel with these frozen life forms inside the upper crust and thereafter hitting the host planet the heat bring back them to life (as its a natural phenomenon that orbits can switch and move out, Tidal force explains this)
It doesn't explain the origin of life but only how it has come to earth.
Based on continued analytical and empirical studies, we just found an interstellar object recently in 2017 "Oumuamua"(don't ask me how to spell it). Its the first non-solar-system objects in the solar system we got to observe. It is a revolutionary observation that took the astronomical society by surprise. The orbit is very complex a near hyperbolic orbit(Generally all orbits in our solar system are either circular or elliptical). This strongly supports "Interstellar panspermia".And there's a heated debate that it's an alien spacecraft because of its Cigar shape. Even more recently in December 2019, there's another interstellar visitor named "2I/Borisov", its a comet this time and still the research is going on this thing.
This area of science is so vast that I won't be able to explain everything in one article, let's keep our article to the basic ideas.
The Mystery Continues
The study of the universe is a fascinating subject. We not only get some insights about the basic understandings of the universe but also it helps find the true purpose of living. There we are from all the great knowledge from the centuries of quest the true answers for the biggest questions remain a mystery. It could be a merely random event in complex molecules, rather an accidental leftover from a much intelligent and advanced species. Whatever the true answer is, we always ask questions, the unknown is what makes us curious and drives us for a much better understanding of life. We only have one life to live, let us make it a good page in the book of mankind.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2020 Srujith rytes