The origins of life on earth
What are the origins of life on Earth? This question has been highly debated by scientists for a long time. Scientists are trying to determine what makes Earth so unique that life thrives here but in no other planets that we are aware of. There are several theories that scientists have proposed in trying to determine the origins of life on Earth. Some theorize that life derived from an extraterrestrial source, others believe autotrophs were the source, and other groups hypothesizes that heterotrophs were the origin of life on Earth. Currently, the heterotroph hypothesis is the most accepted theory of how life started on Earth, but there are proponents of the other theories, as well. It was put forward that there was actually an extraterrestrial source for life on Earth based on evidence that scientists found from meteorites that crashed into Earth. According to Enger, Ross and Bailey (2007), “Early in the 1900s, Swedish scientist Svante Arrhenius popularized the idea of panspermia. Panspermia is the concept that life arose outside the Earth and that living things were transported to Earth to seed the planet with life” (p. 414). Scientists studying meteorites found that they carried organic materials from where they originated which helped to carry the belief forward that life may have started elsewhere. That would mean that life originated from another planet and was able to be transplanted to Earth. Scientists believe that life may have existed on Mars at one time and it may have spread by a meteorite to the Earth where it found an environment that allowed it to thrive and evolve into what it is today.
Another theory is that heterotrophs were the first living organisms on the planet. “According to the heterotrophic hypothesis the first living beings were very simple heterotrophic organisms, i.e., not producers of their own food, which emerged from the gradual association of organic molecules into small organized structures (the
Another theory is that heterotrophs were the first living organisms on the planet. “According to the heterotrophic hypothesis the first living beings were very simple heterotrophic organisms, i.e., not producers of their own food, which emerged from the gradual association of organic molecules into small organized structures (the
References: Enger, E. D., Ross, F. C., & Bailey, D. B. (2007). Concepts in biology (12th ed.). Boston: McGraw-Hill. Origin of Life. (2013). Biology Questions. Retrieved May 19, 2013, from http://www.biology-questions-and-answers.com/origin-of-life.html