Earth is the only planet we know of that can support life. This is an amazing fact, considering that it is made out of the same matter as other planets in our solar system, was formed at the same time and through the same processes as every other planet, and gets its energy from the sun.
To a universal traveler, Earth may seem to be a harmless little planet in the far reaches of one of billions of spiral galaxies in the universe. It has an average size star of average brightness and is joined by seven other planets — which support no known life forms — in its solar system. While this may be fitting for a passage from The Hitchhikers Guide to the Galaxy, by Douglas Adams, in the grand scheme of the universe, it would be a fairly accurate description.
However, Earth is a planet teeming with vitality and is home to billions of plants and animals that share a common evolutionary track. How and why did we get here? What processes had to take place for this to happen? And where do we go from here? The fact is, no one has been able to come close to knowing exactly what led to the origins of life, and we may never know. After 5 billion years of Earth’s formation and evolution, the evidence may have been lost. But scientists have made significant progress in understanding what chemical processes that may have led to the origins of life.
There are many theories, but most have the same general perspective of how things came to be the way they are. Following is an account of life’s beginnings based on some of the leading research and theories related to the subject, and of course, fossil records dating back as far as 3.5 billion years ago.