I would love to post a response to this. It may not be that long, but, I love homework, NOT!
I hypothesize that life on Earth was carried here on comets, and asteroids. Basic organic materials exist on these stellar bodies, and they are the base components of proteins. The first "spark" of life on the planet was probably some type of RNA, or virus as we now call them. These strands slowly evolved into DNA on a stifiling protoplanet, and later on into simple single celled organisms.
Extremophiles live at the depths of the ocean in hydrothermal vents, as well as other "toxic" environments, and metabolize energy by chemosynthesis, such as a diet of sulphur. They may be similar to the early single celled organisms that evolved on the planet, and then slowly adapted to the cooler temperatures as the Earth aged, and water began to be in abundance. They more than likely slowly evolved into stromatolites, which were the first known life in the fossil record to produce oxygen.
Do me a big favor, don't plagiarize, and expand on this to call it your own work.


