Scientists believe that the Earth was formed about 4.6 billion years ago. Life on Earth arose very quickly after its formation. There are many theories of how life originated, however few have ever been totally proven. . In this paper, I will discuss only three. Did life begin from extraterrestrial sources? Did life originate as a heterotroph or did life originate as an autotroph?
In the 1900’s a Swedish scientist, Svante Arrhenius, proposed the idea of panspermia. This concept dictates that life arose from outside of Earth and was transported here to seed the planet with life. Does this mean that human like life forms were transported to Earth? No! It means that after Earth’s formation, living organisms known to live in meteorites and outer space landed on our planet and in our oceans. These beliefs can be backed by scientific proof by examining meteorites and large thermal vents located on the ocean floor.
Many scientists believe that the first living things on Earth were heterotrophs, which lived off of organic molecules in the oceans. Evidence shows a vast variety compounds in the oceans, because they existed there before evidence of oxygen in the atmosphere, they would have to have been anaerobic organisms, and could not obtain enough energy from the organic molecules in their environment. Due to a population increase caused by reproduction, heterotrophs should have died because of a lack of organic materials to consume. These compounds survived, because, due to mutation in their nucleic acid.
Recent discoveries have prompted…