Biologists disagree quite over exactly where life first appeared on Earth, and may have evolved on the ocean floor, in shallow rock pools, from clumps of asteroid impacts or perhaps all of the above.
Monday, Live Science magazine considered that “all life forms on Earth need water to survive, so it is possible that life evolved there first, but water alone is not sufficient to create life; It also needs energy,” reports Al-Rai daily.
Today, most organisms get their energy from metabolic sugars, but these molecules did not exist 3.7 billion years ago when life first evolved. So what energy sources were available to help Earth’s first creatures emerge?
“About 4.6 billion to 4 billion years ago, the Earth was very much an ocean, with the occasional volcanic island erupting from the water,” the magazine added.
“One theory about the origin of life is that ultraviolet radiation from the sun helped create complex molecules in shallow rock pools on volcanic islands,” biologist Eloy Camprubi Casas, who studies the origins of life at the University of Texas, told the magazine.
Another theory about the origin of life on Earth posits that the building blocks of life resulted from asteroid collisions, which were more common 4 billion years ago than they are today, according to Partha Bira, an investigative scientist at NASA’s Bay Area Environmental Research Institute.
These bodies are exposed to sunlight for millions of years, and the roots produce active components that can interact with each other even at low temperatures.
“Radicals are atoms, molecules or ions that have an extra electron, which makes them ready to interact with anything,” Pera explained to the magazine.
According to this hypothesis of the origin of life, when those asteroids hit the Earth, the highly reactive molecules would have mixed with other simple molecules in the ocean to create the complex chemistry needed to start life. In this case, Bira indicated, the energy source would also be geothermal.
