What if the story of life on Earth isn't what you think it is?

[mr blur]

(*Spoiler*: it didn't all start 6,100 years ago )

From single cells through lumbering amphibians to men with spears. We all know ‘the story of life on Earth’. But whose story is it?

Mark Carnall

Mark is Life Collections Manager at Oxford University Museum of Natural History

[center]
This is the Geologic Time Spiral. If you look closely you’ll see that humankind is represented by a surfer.[/center ]

The scientific story of life on Earth, as told in palaeontology books for children, museum displays, documentaries and even on university courses is always the same. It begins with the creation of the universe, then the Earth, represented more often than not by exploding volcanoes. Microscopic single cells bob in the ocean, dividing and swelling, morphing into things with a noticeable front end and a back end.

Skip forward a couple of billion years, and emblematic fossils, the trilobites, are scuttling around the ocean floor. Chances are that ammonites are floating around too. Then we get to the more familiar beats: the story proper finally starts. The Age of Fishes kicks off in the Devonian, 400 million years ago with fish that look a bit different to today’s fish, but not different enough for us to care. Fish-headed salamanders then triumphantly flop onto a green and verdant land. Then it’s the glorious Age of Reptiles, unanimously depicted by Tyrannosaurus rex locked in eternal conflict with mortal enemy Triceratops. From between the feet of stomping dinosaurs, ratty animals scurry about; cue an asteroid impact and the Age of Mammals begins. The rest you could fill in yourself, rat climbs a tree, becomes a monkey takes a few more steps and is then a man at last!

<snip >

http://www.theguardian.com/science/blog/2015/nov/30/what-if-the-story-of-life-on-earth-isnt-what-you-think-it-is

[NeoGreen]

1. Not unlike something I have pondered...

...(lightly). The hypothesis known as Life Before Earth.

Life Before Earth

Alexei A. Sharov, Ph.D.
Staff Scientist, Laboratory of Genetics
National Institute on Aging (NIA/NIH)

Richard Gordon, Ph.D.
Theoretical Biologist, Embryogenesis Center
Gulf Specimen Marine Laboratory

Abstract
An extrapolation of the genetic complexity of organisms to earlier times suggests that life began before the Earth was formed. Life may have started from systems with single heritable elements that are functionally equivalent to a nucleotide. The genetic complexity, roughly measured by the number of non-redundant functional nucleotides, is expected to have grown exponentially due to several positive feedback factors: (1) gene cooperation, (2) duplication of genes with their subsequent specialization (e.g., via expanding differentiation trees in multicellular organisms), and (3) emergence of novel functional niches associated with existing genes. Linear regression of genetic complexity (on a log scale) extrapolated back to just one base pair suggests the time of the origin of life = 9.7 ± 2.5 billion years ago. Adjustments for potential hyperexponential effects would push the projected origin of life even further back in time, close to the origin of our galaxy and the universe itself, 13.75 billion years ago. This cosmic time scale for the evolution of life has important consequences: (1) life took a long time (ca. 5 billion years) to reach the complexity of bacteria; (2) the environments in which life originated and evolved to the prokaryote stage may have been quite different from those envisaged on Earth; (3) there was no intelligent life in our universe prior to the origin of Earth, thus Earth could not have been deliberately seeded with life by intelligent aliens; (4) Earth was seeded by panspermia; (5) experimental replication of the origin of life from scratch may have to emulate many cumulative rare events; and (6) the Drake equation for guesstimating the number of civilizations in the universe is likely wrong, as intelligent life has just begun appearing in our universe. Evolution of advanced organisms has accelerated via development of additional information-processing systems: epigenetic memory, primitive mind, multicellular brain, language, books, computers, and Internet. As a result the doubling time of human functional complexity has reached ca. 20 years. Finally, we discuss the issue of the predicted "technological singularity" and give a biosemiotics perspective on the increase of life’s complexity.

as illustrated in the following chart:


It is one of those things that makes me go, hmmm...

[AtheistCrusader]

2. Given the nature of a couple life forms genomes (tardigrades and octopus) I think it reasonable

to assume, not all life on earth originated here.

It's at least a strong possibility at this point.

[Yorktown]

3. To build up on neogreen's graph

The Churyumov-Gerasimenko comet is 6.45 Bn yrs old (2Bn more than the earth),

holds organic molecules http://www.popsci.com/philae-finds-organic-molecules-comet

and might have held microbes: http://technology.inquirer.net/43013/philaes-comet-may-host-alien-life-astronomers

Consistent with the very interesting graph.