Mankind has a common quest for knowledge that binds everyone on the planet. Man’s greatest question has to do with his origins, not as an individual, but as a life form. This topic of the origin of life has been a perplexing one and at present, there are many theories, but no conclusive answers. It is agreed that life evolved from simple to complex, but there are many possibilities as to where and how these processes began. There are seven major theories as to the simplest life forms on earth came into existence and how they began their long road to become evolved beings.
The first theory is that life arose from a primordial soup in the oceans and that is the result of random chemical reactions (Choi, intro). The second theory is the electric spark theory. This theory stems from the ability to electrical sparks to generate amino acids and sugars from an atmosphere containing water, methane, ammonia, and hydrogen. The theory is that larger and larger building blocks of life were generated over time. The underlying process in this theory is that volcanic action spewed these chemicals into atmosphere where lightning transformed them into the building blocks of life (Choi, p. 7). Another theory is that life was formed in clay. The theory is that the clay served to collect compounds that eventually organized into DNA (Choi, p. 6).
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The fourth theory is that life arose from hydrogen vents located in the bottom of the ocean. These vents served to concentrate molecules and provided mineral catalysts (Choi, p. 5). Many scientists agree that life is about 3 billion years old. At that time the sun was about 1/3 as bright as it is today. There is a theory that a layer of ice hundreds of feet thick protected organic compounds from ultraviolet light and destruction from cosmic events (Choi, p. 4). It is believed that RNA existed long before DNA. However, RNA theories fail to explain how the RNA got here in the first place (Choi, p. 6). Another theory is that life evolved from simple molecules interacting in capsules that acted similar to cell walls. The RNA theory says that RNA developed first. The simple molecules in a capsule theory considers metabolism to be the first life process to develop (Choi, p. 8).
As one can see, there are many different ideas on where and how life began. The question is which one is right. Humanity may never know the real answer, but evidence exists for some theories more than others. To begin this journey, one could begin with the fossil record. For instance, ancient one celled organisms that are called microfossils (Berkley University). One of the key difficulties with studying microfossils is that some natural mineral formations can resemble life. It is difficult to determine if the fossils is a living organism, or the result of a chemical reaction (Berkley University). Even so, one celled microfossils still only date back to 2 billion years old, which means that they are still far more advanced than the origins of life.
The final theory is known as the Panspermia hypothesis. This hypothesis is that life came to earth via asteroids, meteors, and other forms of space dust (Choi, p. 1).Support for the theory that life was brought here from asteroids is not necessarily based on the life, but on the basic building blocks of life. The theory is that that impact craters brought the chemical components of life together and then acted as a crucible in which to “cook” them, Evidence for this theory comes from microfossils found in and around hydrothermal crater basins (Davis).
A physicist from MIT believes that he has an equation that explains the origin of life. According to the equation, if you take a clump of chemicals and shine light on them, over time photosynthesis will develop and the first plant life will emerge (Wolchover).This theory depends on the law of entropy and the laws of thermodynamics as its basis. The idea is that chemicals will arrange themselves, over time, so that they resonate better and operate more efficiently within the system.
Most theories that explain how complex, rather than simple life, began to develop center around oxygen. These theories propose that life began to achieve more complex forms at the same time when atmospheric levels of oxygen began to rise, about 630 to 635 million years ago (Nature World News). However, a certain type of sea sponge has been found that can thrive in oxygen levels as low as 0.5 percent that of today’s oxygen levels (Nature World News). This means that it is possible for complex to have existed long before 635 million years ago. Sea sponges may have been the first living animals.
There are no scientific theories that have been challenged more than those surrounding the origins of life. These theories are in agreement that life arose from a chemical soup through some mechanisms. The biggest debate is whether this is due to the intervention of some entity, or whether it was simply the result of random chance (White, p. 455). On this topic, the arguments are a matter of theory at this point. All of these theories agree that life arose from the combination of chemical compounds into increasingly complex forms. At which point life began to be distinguished from other chemical compounds is another point of debate regarding life’s origins. This is the common thread that binds a majority of the theories of life together. They agree on these points, but disagree as to the setting in which this occurred. To understand the origin of life, man must be able to see before the first fossil record, a time where no record exists. This is the conundrum that scientists face regarding the origin of life and the reason why man may never know the answers to these questions. He may come close, but will never know for certain.
