Why we are here: Double membrane prokaryotes! Say Again?

William Atkins
Thursday, 20 August 2009 19:40

Science - Biology

The NASA article explains, “This endosymbiosis, or merging of two cells, enabled the evolution of a highly stable and successful organism with the capacity to use energy from sunlight via photosynthesis.”

“Further evolution led to photosynthetic organisms producing oxygen as a byproduct. The resulting oxygenation of Earth's atmosphere profoundly affected the evolution of life, leading to more complex organisms that consumed oxygen, which were the ancestors of modern oxygen-breathing creatures including humans.”

Lake states within the NASA article “Higher life would not have happened without this event. These are very important organisms. At the time these two early prokaryotes were evolving, there was no oxygen in the Earth's atmosphere. Humans could not live. No oxygen-breathing organisms could live."

The article continues, “The genetic machinery and structural organization of these two organisms merged to produce a new class of prokaryotes, called double membrane prokaryotes. As they evolved, members of this double membrane class, called cyanobacteria, became the primary oxygen-producers on the planet, generating enough oxygen to alter the chemical composition of the atmosphere and set the stage for the evolution of more complex organisms such as animals and plants."

Carl Pilcher (director of the NASA Astrobiology Institute, Ames Research Center, California) concludes, “This work is a major advance in our understanding of how a group of organisms came to be that learned to harness the sun and then effected the greatest environmental change Earth has ever seen, in this case with beneficial results.”
 
Additional information is found on the ScienceDaily.com article “Research Reveals Major Insight Into Evolution Of Life On Earth.”