LIFE: HOW DID IT ALL BEGAN?

If there is any question that has befuddled the mind of even great scientists even born, it is the question of how life began and whether science can answer such a question. In fact, it is because such a question irks the sensibility of the religious ones, both the lowly and those on the corridor of power, that most scientists shy away from attempting to answer the question. Also, it is likely people will refer to the famous work of Charles Darwin about evolution when topics like this are discussed. However, first thing to clear out is that Darwin never attempted to explain the origin of life. What he did was to explain the origin of species. And yes, he claims that given the evidence available to him, all life seems to have evolved from a common origin of simple life form. How this simple life form came to be, he never did venture to explain. Darwin was not even the first person to notice that the physical and structural form of animals do change over time, and came up with the idea of evolution of animals through time. He only introduced the ways through which this evolution works: natural selection through survival of the fittest and mutation. Nevertheless, the theory of evolution through natural selection as propounded by Darwin was so successful in explaining the diversity of life forms that some enthusiasts have extended it to explain the origin of life. Ambitious? Yes, but definitely not blasphemous; at least not in scientific sense. How life began in the cosmos might be a mystery, but it is not in the spirit of science to rhapsodise mystery – science thrives in demystifying hitherto mystery. This article therefore attempts an overview of the various theories propounded in an attempt to explain how life appeared in the universe and experiments carried out to substantiate them.
In discussing a topic as important as this, it is good, in spirit of fairness, to start with the age old Creationism theory that permeates almost all religions. In scientific parlance, and to juxtapose it against the activities of computer technologists of nowadays, it is also called Intelligent Design Theory. It may also be called scientific creationism or creation science. This theory holds that an intelligent being or some intelligent beings, purposefully created life on earth. This intelligent being(s) has being variously referred to as the Creator, God or gods. Although this theory is not scientific because it cannot be verified or falsified using scientific methods, it is important to science because it is in its rejection that most other theories sprang up. For convenience, and for the fact that we live in era of monotheistic religions, let us refer to this intelligent being as a singular person and using a male pronoun. This intelligent, conscious creator purposefully designed life either out of inorganic materials of the earth or out of both the inorganic materials (dirt) and his own essence (breath). Every word in this last sentence is controversial and has polarised scientists who subscribe to it to extreme creationists/intelligent design advocates or moderate ones. Belonging to this category are scientists such as Maciej Giertich, a population genetist; Keneth W. Funk and Englin Dennis, a professor of biological science and Dwain L. Ford who has his PhD in Chemistry from Clark University.
The design theory has its major support in the discovery of genes that make up the chromosomes of the living cell. Proponents of this theory believe that the substance, structure and function of a single strand of our gene are so complex that the odd that they came into existence through unguided blind occurrence is highly improbable whichever way one turns. The DNA and RNA; deoxyribonucleic and ribonucleic acids that make up the nucleic acid molecule in the form of a twisted double helix string of chromosomes and carries genetic information, is such intricately designed that a nano glitch could cause grave changes at the macro level of the features of the owner of such gene. To evolutionists, this is not a problem though, in fact, it is expected according to them.
The second thing is by regarding genetic information stored in the amino acid of the DNA and RNA as “codes,” evolutionists among the scientists are boxed to a corner because it will not make sense to talk of genetic code without suggesting somebody wrote the code. Coding is a deliberate and purposeful action by an intelligent being or beings. However, on the other hand, scientists also observe that “dumb errors” do occur in the coding structure and operation of genes which is expected if it were of natural occurrence.
Another scientifically significant theory is the Primordial Soup Theory. This theory derives from what scientists have learned so far in the fields of biology especially microbiology, chemistry, astrophysics and geophysics. The theory holds that life might have developed out of some chemicals compounds that happened to be in an enclose, such as puddle or the bottom of the ocean about four billion years ago. The Russian chemist, A. I. Oparin and the great English geneticist, J. B. S. Haldane, were the first to propound the theoretical hypothesis guarding the research in the 1920s, although they developed the hypothesis separately. Invariably, the two of them argued that the primitive atmosphere of the earth, the chemical composition of earth and the naturally occurring events of this geologic period could have brought about the development and emergence of the basic organic building blocks of life; molecules whose system of relation with one another eventually became what we now call life.
For this to happen, the condition of the earth at this time may not be what it is today, the emergent system of molecules that formed life will have to be self -replicating in the “organic soup.” The replicators, having gathered to form another system, other characteristic of life soon followed, such as a somewhat type of nutrition that allow the organism to ingest chemical compounds to refuel and sustain its internal workings. Oparin and Haldane therefore believe life began as simple heterotrophs feeding on organic compounds similar or different to its own. Then from this situation the organism stumbled on mutation which is a random change/alteration in the nucleic acid sequence of the genotype of an organism resulting in a new trait or characteristic that can be inherited which could be beneficial, neutral, or harmful in effect. Later, autotrophs emerged; perhaps courtesy mutation. Autotrophs synthesise their food individually using the energy of the sun or other sources of energy.
Oparin's and Haldane's hypothesis was famously tested experimentally first by Chemists Stanley Miller and Harold Urey in the early 1950s. To simulate what they thought will be the condition and components of the early earth’s atmosphere, Miller put into a pair of closed glass containers, a mixture of the gases methane (CH4), water vapour (H2O), ammonia (NH3) and hydrogen (H2) connected by glass tubes. Iron filaments were added to send electrical charges into the flasks, representing thunder and lightning in the primitive atmosphere. The result of Miller and Urey were electrifying in the science world. They were stupefied to see the electrical discharges causing the gases to form into somewhat complex organic molecules comprising amino acids, the building blocks of the genetic proteins, raining down to the bottom of the flasks out of the artificial atmosphere. Scientists have further shown that organic compounds such as all of the 20 amino acids found in genes and various sugars and phosphates which form the structure of DNA and RNA could be produced by many kinds of energy: sun’s ultraviolet light, heat from sun and from volcanoes, and even shockwave from the impact of colliding meteorites.
However, Miller and Urey’s experiment faces a number of objections in the science world. It is one thing for a number of amino acids to form from sparks of some gaseous or chemical soup in a simulated environment, it is another thing for the compounds to arrange themselves into that complex structure of DNA and RNA and perform the job of detailed information storing and replicating itself perfectly. Another thing is that there is no guarantee that all the gaseous elements and the chemicals in the experiment were a perfect replica of the same condition that was during the time life emerged on earth. About four billion years ago, the earth's atmosphere probably contained mostly N2, CO2, water vapour (H2O), and perhaps some carbon monoxide (CO) according to new discovery in geoscience. If this is so, it cast a serious doubt to the randomness state presupposition leading to the primordial soup theory. At most, it shows that there could have been fine tuning of the ingredients of life (perhaps by higher intelligence) just as Miller and Urey could be accused of choosing gases that will only bring about the result that turned out.
However, Miller and Urey’s experiment is a watershed in the scientific odyssey into the origin of life. It restores hope into the scientific community that following the scientific methods of enquiry, there is high possibility that scientist will one day stumble on the secret of how life came into existence on planet Earth.
Another theory worth mentioning is panspermia; although a theory having its root in esotericism because it believes life came from the outer space. Its scientific variant holds that life on earth could have originated from organisms, or self-replicating amino-acids, formed in outer space. This theory did not receive serious scientific attention until recently. The reason for this is not far-fetched: to think life, or the building block of it could develop in a state of weightlessness and lack of air seems a crazy idea. However, the synthesis of organic molecules that was observed in the Miller-Urey experiments, it was soon discovered, may not be prerogative of happenings on the surface of the earth alone. The expanse of space provides ideal laboratory for chance or randomness to come up with organic matter to father life and there has been new discoveries in this respect. Space missions and probes, especially with Halley's Comet discovered abundant organic compounds in different region of space and the moons of Jupiter and Saturn. Also, meteorites that fell to earth during the early stages of the great earth bombardment may have imported complex organic molecules that later became the building blocks of life.