There was no life present on Enod five billion years ago. During this time, there was a reducing atmosphere. The first atmosphere consisted simply of hydrogen gas (H2). This gas did not remain near the surface because Enod's gravity could not hold the molecules. The second early atmosphere consisted of nitrogen gas, hydrogen gas, carbon dioxide, methane gas, and some water vapor. There was no oxygen. Gradually, the first seas formed from torrential rains that began when Enod had cooled enough for water in the atmosphere to condense. During this early time Enod displayed a very unstable atmosphere and surface. Intense volcanic and lightning activity slowly continued to formulate Enod's atmosphere as we know it today. A growing atmosphere and chemical conditions on the early Enod set the stage for the origin and evolution of life on Enod. It is believed that the first signs of life originated near the surface of Enod's oceans. These oceans provided just the right ingredients and chemical reactions to spark life on Enod. This new aqueous solution contained carbon and nitrogen, the most important elements of life. These and other elements later reacted to form amino acids, carbohydrates, and some forms of nucleotides. All the elements and molecules combined formed what is known as the "Primordial Soup." Life began in water and evolved there for three billion years before spreading onto land. The first cells contained about 70% to 95 % water within their thin membranes. Although Enod's first living cell was composed mainly of water, most of the rest consisted of carbon-based compounds. Proteins, DNA, carbohydrates, and other molecules helped formulate the first living cell. With time,the cell continued to differentiate and adapt to different aqueous environments as the temperature and concentration levels of elements changed in the water. These conditions lead the first cell to differentiate and develop new mechanisms that would ensure its survival.

THE FIRST CELL

The first cells to form on planet Enod were very similar to the prokaryotes found on Earth. Prokaryotes were the earliest organisms, and they lived and evolved all alone on Enod for 2 billion years. These cells are relatively small and lack membrane-enclosed organelles. They have a cell wall external to their plasma membranes. The wall maintains the shape of the cell, provides physical protection, and prevents the cell from bursting. The first prokaryotes, also known as archaeprokaryotes, did not have any mobility mechanism. They simply drifted with the current of the ocean in which they thrived. The archaeprokaryotes evolved in extreme environments. They dwelled near the hot water at the openings of deep-sea vents. These ancient prokaryotes had a unique form of energy metabolism. Hydrogen was used to reduce CO2 to methane. However, as early prokaryotes evolved, they were met with constantly changing physical and biological environments. This changes lead to the adaptation of new metabolic capabilities and mechanisms for self-locomotion.

Reproduction The early prokaryotes living on Enod reproduced asexually by a type of cell division called binary fission. The parent cell produces genetically identical offspring by replicating the chromosome and then budding the membrane into a separate cell.