Mapping the Bio Cosmos

The Third Domain, by Tim Friend, is the untold story of how the discovery of a new form of life, archaea - biochemically and genetically unique organisms that live and thrive in some of the most inhospitable environments on Earth - was first ridiculed, then ignored for thirty years by mainstream scientists - is revolutionizing science, industry, and even our search for extraterrestrial life.

 

Starting with Carolus Linnaeus in the 17th century, scientists have long struggled to order and categorize the many forms of life on Earth. But by the early 20th century the tree of life seemed to have stabilized, with two main domains of life at its roots: single-celled and multi-celled organisms. All creatures fit into one of these two groups. Or so we thought.

But in 1977, a lone scientist named Carl Woese determined that archaea were a distinct form of life, unlike anything seen on Earth before. This shocking discovery was entirely incompatible with the long-standing classification of life as we know it. But as it turned out, archaea were not life as we know it, and the tree of life had to be uprooted once again. Now, archaea are being hailed as one of the most important scientific revelations of the 20th century.  Microbes are responsible for many biogeochemical cycles and are crucial to the continued function of the , Woese's efforts to clarify the evolution and diversity of microbes provided an invaluable service to ecologists and conservationists.

Woese’s big idea is that primitive life existed as a community of cells that freely exchanged genes. They shared a basic translation system for making proteins, but had little else in common. These cells evolved as a community and not as distinct lineages. Before Woese, the tree of life had two main branches called prokaryotes and eukaryotes, the prokaryotes composed of cells without nuclei and the eukaryotes composed of cells with nuclei.

Woese refers to this time as the “progenote era” where the word “progenote” refers to a cell that has not yet established a definite link between a stable genotype and a heritable phenotype. At some point in time, certain cells make the transition from progenote to the founders of a stable lineage. The transition point is known as the “Darwinian threshold.”

"The real mystery, however," writes Woese, "is how this incredibly simple, unsophisticated, imprecise communal progenote—cells with only ephemeral genealogical traces—evolved to become the complex, precise, integrated, individualized modern cells, which have stable genealogical records. This shift from a primitive genetic free-for-all to modern organisms must by all accounts have been one of the most profound happenings in the whole of evolutionary history. Although we do not yet understand it, the transition needs to be appropriately marked and named. “Darwinian threshold” seems appropriate: crossing that threshold means entering a new stage, where organism lineages and genealogies have meaning, where evolutionary descent is largely vertical, and where the evolutionary course can begin to be described by tree representation."

The Third Domain tells the story of their strange potential and investigates their incredible history to provide a riveting account of an astonishing discovery.

Posted by Casey Kazan.

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Non-Carbon Lifeforms -Why We May Overlook Extra-terrestrial Life

Did Life Originate from Clay -Science Fiction or Reality?
Life from the Center of the Earth - The Shadow World of Our Hidden
Is There Life on Mars? NASA Goes Underground to Find Out
What Lies Beneath -A Mystery at the Earth's Center
Unknown Species of the Underworld Discovered

Source: http://www.amazon.com/Third-Domain-Tim-Friend/dp/product-description/0309102375

Comments

[jer35mx]

And how did it survive to be founded and theorized.