A cold origin

Brinicles, filmed forming in situ for the first time in 2011, were presented as fingers of death. But Julyan Cartwright and others observe that they create chemical gradients, electric potentials and membranes – that, is all the conditions necessary for the formation of life.

Brinicles, says a post via MIT Technology review, could be ubiquitous on ocean bearing planets and moons such as Europa, where they might play equally interesting roles.

Yeti crab

Thirty-fifth in a series of notes and comments on The Book of Barely Imagined Beings

Chapter 26: Yeti crab

page 355: (marginal note) Carl Woese died in December.  One overview of the man and his ideas here.  Last year, Prof. Woese kindly approved quotes from A New Biology for a New Century on page 140 and 376 of this book.

page 356: variations upon the crustacean body form. A striking example can be seen in these photos of a spider crab and a ghost shrimp. One of my favourites is the Harlequin shrimp:

page 359: robots and our attitudes towards them...the start of a mechanical Cambrian explosion.  The military is a major driver. See, for example, the DARPA robot challenge and AlphaDog. Debate on the use of drones, and what comes next is extensive. See here, here or here. In a recent overview Peter W. Singer suggests that:

the biggest ripple effect of the robot...is in reshaping the narrative in [the] realm of war. We are seeing a reordering of how we conceptualize war, how we talk about it, and how we report it.

Robert Ito details some of the quirks of interactions between humans and social robots.  Izabella Kaminska considers the robot economy and the new rentier class. Noah Smith has some suggestions as to how to fairly distribute income and wealth in the age of the robots.

page 360: the place where life emerged from non-life.  Previous posts on this topic are collected under the label Origin.  See also The beginnings of life: Chemistry’s grand question.  Jack Szostack suggests that somewhere on Earth, over 3.5 billion years ago, a bubble of fat spontaneously broke into smaller ones, giving rise to one of life's most fundamental properties - the ability to make copies of itself.

page 362: a stream of order. Vlatko Vidral makes a case for information as the surprise theory of everything.

page 364: travel to the bottom of the sea. The biggest driver for doing so is likely to be resource extraction. See A Gold Rush in the Abyss and this article arguing exploration is inevitable. More reports here and here.

The body electric

cells are powered not by chemical reactions, but by a kind of electricity, specifically by a difference in the concentration of protons (the charged nuclei of hydrogen atoms) across a membrane. Because protons have a positive charge, the concentration difference produces an electrical potential difference between the two sides of the membrane of about 150 millivolts. It might not sound like much, but because it operates over only 5 millionths of a millimetre, the field strength over that tiny distance is enormous, around 30 million volts per metre. That's equivalent to a bolt of lightning.

...this [is] electrical [the] driving force the proton-motive force. It sounds like a term from Star Wars, and that's not inappropriate. Essentially, all cells are powered by a force field as universal to life on Earth as the genetic code. This tremendous electrical potential can be tapped directly, to drive the motion of flagella, for instance, or harnessed to make the energy-rich fuel ATP.

However, the way in which this force field is generated and tapped is extremely complex. The enzyme that makes ATP is a rotating motor powered by the inward flow of protons. Another protein that helps to generate the membrane potential, NADH dehydrogenase, is like a steam engine, with a moving piston for pumping out protons.

-- from Life: is it inevitable or just a fluke? in which Nick Lane once again champions the hypothesis that the proton gradient at deep sea alkaline vents drove the origin of life on Earth.  'Far from being some mysterious exception to the second law of thermodynamics...life is in fact driven by it.'

Lane argues that similar circumstances would necessarily hold on other planets, but that the jump to eukaryotic cells is likely to be vastly rarer.

Cellular origins in a viral world

The discovery of an unusual hybrid virus living in one of the harshest environments on the planet suggests a solution to the conundrum of how RNA-based life 'updgraded' to DNA-based life. More

P.S. A good phrase: "It's a mythological beast of a virus, but it actually exists.”

Souped up

Armen Mulkidjanian makes the case that life as we know it originated in freshwater thermal springs not unlike Darwin's warm little pond. Jack Szostack is sympathetic but Nick Lane continues to argue that deep sea vents are a more likely starting point. Martin Brasier, who discovered the oldest fossils so far -- 3.43 billion year old bacteria in Australian rocks -- holds fire. He says 'The rock record is the only safe witness we have.'

I tried to cover these issues in outline in the Xenophyophore and Yeti crab chapters my forthcoming book.  It looks as if I didn't go too far wrong.

Climbing in 190 dimensions

Those who have looked at the night sky—not the dim remnant visible in cities, but the bright complexity seen in high, dark places—can appreciate the task assumed by Wochner et al [who] describe the construction of an RNA enzyme (a template-dependent primed RNA polymerase) that emulates an ancient molecule that would have been crucial in the “RNA world,” believed to have predated DNA- and protein-based life. To find this enzyme, they searched vast molecular populations, holding potentially many, many more RNAs than the visible universe has stars...

...An RNA polymerase capable of Darwinian evolution is now a large step closer. In the old days (say, 2007), we could template product RNAs that were only 8 to 11% as long as the polymerase. Now we are at 48%. One prediction of the 190-dimensional view is that there is likely to be a route leading up to longer RNA transcripts, if only we can find it. With luck, the very next slopes will take us to Darwinian altitudes, where we have not been before...

-- from Climbing in 190 Dimensions by Michael Yarus

Let's rock

The picture painted by Russell and Martin is striking indeed. The last common ancestor of all life was not a free-living cell at all, but a porous rock riddled with bubbly iron-sulphur membranes that catalysed primordial biochemical reactions. Powered by hydrogen and proton gradients, this natural flow reactor filled up with organic chemicals, giving rise to proto-life that eventually broke out as the first living cells - not once but twice, giving rise to the bacteria and the archaea.

Many details have yet to be filled in, and it may never be possible to prove beyond any doubt that life evolved by this mechanism. The evidence, however, is growing. This scenario matches the known properties of all life on Earth, is energetically plausible - and returns [Peter] Mitchell's great theory to its rightful place at the very centre of biology.

-- from Was our oldest ancestor a proton-powered rock? by Nick Lane

Starting out

When you're young, all evolution lies before you...If you compare yourself with the limitations that came afterwards, if you think how one form excludes other forms, of the monotonous routine where you finally feel trapped, well, I don't mind saying, life was beautiful in those days.

--'Qfwfq'

Warm little pond

[John D. Sutherland] has solved a problem that for 20 years has thwarted researchers trying to understand the origin of life — how the building blocks of RNA, called nucleotides, could have spontaneously assembled themselves in the conditions of the primitive earth. The discovery, if correct, should set researchers on the right track to solving many other mysteries about the origin of life. It will also mean that for the first time a plausible explanation exists for how an information-carrying biological molecule could have emerged through natural processes from chemicals on the primitive earth.

Blobs of goo

Organisms rather like sponges may have been the first multicellular animals some 850 million years ago.


(see also: Sponge larvae: 'Your unlikely ancestors')

'Older', and 'everywhere'

• Traces of [multicellular] animal life have been found in rocks dating back 635 million years.

• research claims there are at least 361 intelligent civilisations in our galaxy and possibly as many as 38,000. [1]

(See also Just wondering)

Footnote

[1] 15 Feb: Galaxy has 'billions of Earths'.

1859 and all that

John Whitefield considers the woodpecker at the start of his Blogging 'The Origin'.

Did Darwin know about the Woodpecker's fellow Piciformes, the Honeyguides?

Science magazine begins a blog on the origin of life.

Vestige of a beginning?

The stage was set for life probably 4.4 billion years ago, but I don’t know if the actors were present.

-- Stephen J. Mojzsis, quoted in an article reporting suggestions that life may have originated in the Hadean period, considerably earlier the 3.83 billion years old trace of life claimed hitherto.