Jump-Starting Evolution

With the aid of a straightforward experiment, researchers have provided some clues to one of biology's most complex questions: how ancient organic molecules came together to form the basis of life.

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RNA, the single-stranded precursor to DNA, normally expands one nucleic base at a time, growing sequentially like a linked chain. The problem is that in the primordial world RNA molecules didn't have enzymes to catalyze this reaction, and while RNA growth can proceed naturally, the rate would be so slow the RNA could never get more than a few pieces long.

New research found that under favorable conditions (acidic environment and temperature lower than 70 C), pieces ranging from 10-24 in length could naturally fuse into larger fragments, generally within 14 hours.

The RNA fragments came together as double-stranded structures then joined at the ends. The fragments did not have to be the same size, but the efficiency of the reactions was dependent on fragment size (larger is better, though efficiency drops again after reaching around 100) and the similarity of the fragment sequences.

Thor © Marvel Comics

The researchers note that this spontaneous fusing, or ligation, would a simple way for RNA to overcome initial barriers to growth and reach a biologically important size; at around 100 bases long, RNA molecules can begin to fold into functional, 3D shapes. press release

Ref: Nonenzymatic RNA Ligation in Water. 2008. S. Pino, et al. J. Biol. Chem. 283: 36494-36503

Why Viking Lander/Mars? by Ray Bradbury

Art © Alex Nino


© Ray Bradbury
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Originally presented in Star*Reach #6 (1976). Bradbury had read the then new poem at the 1976 San Diego Comic Con a week after the landing of Viking I on Mars. Shortly thereafter Alex Nino agreed to illustrate the poem for publisher Mike Friedrich.

Martian Carbonates Suggest Past Life on Mars

A research team has found evidence of a long-sought carbonates that shows Mars was home to a variety of watery environments, including regional pockets of neutral or alkaline water.

Recent observations from the Mars Phoenix lander has pointed to a period when clay-rich minerals were formed by water, followed by a drier time, when salt-rich, acidic water affected much of the planet. The presence of carbonates indicates that Mars had neutral to alkaline waters when the minerals formed in the midlatitude region more than 3.6 billion years ago.

“Primitive life would have liked it,” said Bethany Ehlmann, “It’s not too hot or too cold. It’s not too acidic. It's a ‘just right’ place.’

The carbonates showed up in the most detail in two-dozen images beamed back by the Compact Reconnaissance Imaging Spectrometer for Mars, an instrument aboard the NASA Mars Reconnaissance Orbiter. Scientists found the mineral near a trough system called Nili Fossae, which is 667 km long, at the edge of the Isidis impact basin. Carbonates were seen in a variety of terrains, including the sides of eroded mesas, sedimentary rocks within Jezero crater and rocks exposed on the sides of valleys in the crater’s watershed. The researchers also found traces of carbonates in Terra Tyrrhena and in Libya Montes.

The carbonates may have been formed by slightly heated groundwater percolating through fractures in olivine-rich rocks. Or, they may have been formed at the surface when olivine-rich rocks were exposed and altered by running water. Yet another theory is the carbonates precipitated in small, shallow lakes. Either way, such environments would have boded well for primitive life forms to emerge.

“We know there’s been water all over the place, but how frequently have the conditions been hospitable for life?” Mustard said. “We can say pretty confidently that when water was present in the places we looked at, it would have been a happy, pleasant environment for life.” press release

Ref: Orbital Identification of Carbonate-Bearing Rocks on Mars. 2008. Bethany L. Ehlmann, et al. Science 322: 1828 - 1832

Dragonella by Wally Wood

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Heroes, Inc. (Presents Cannon) was self published by Wally Wood in 1969. Working with Steve Ditko and Ralph Reese, Wood produced three new strips for the book including the first appearance of “Cannon”. This is Dragonella’s first and only adventure. It’s notable for letting Wally indulge in some medieval scenery including a riff on Prince Valiant.

Dragonella by Ron Whyte & Wally Wood, 1969. © estate of Wally Wood

The Evolution of Superstition

Both Images from The Horror of It All

Abstract: Superstitious behaviours, which arise through the incorrect assignment of cause and effect, receive considerable attention in psychology and popular culture. Perhaps owing to their seeming irrationality, however, they receive little attention in evolutionary biology.

Here we develop a simple model to define the condition under which natural selection will favour assigning causality between two events. This leads to an intuitive inequality—akin to an amalgam of Hamilton's rule and Pascal's wager—-that shows that natural selection can favour strategies that lead to frequent errors in assessment as long as the occasional correct response carries a large fitness benefit.

It follows that incorrect responses are the most common when the probability that two events are really associated is low to moderate: very strong associations are rarely incorrect, while natural selection will rarely favour making very weak associations.

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Extending the model to include multiple events identifies conditions under which natural selection can favour associating events that are never causally related. Specifically, limitations on assigning causal probabilities to pairs of events can favour strategies that lump non-causal associations with causal ones.

We conclude that behaviours which are, or appear, superstitious are an inevitable feature of adaptive behaviour in all organisms, including ourselves.

Article: The evolution of superstitious and superstition-like behaviour.2008. K. Foster and H. Kokko. Proceedings of the Royal Society B 276: 1654.

The Vanguard by Alex Toth

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The Vanguard © The estate of Alex Toth
Originally printed in Hot Stuff #4, 1977

New Region of Earth's Magnetosphere Discovered

Scientists have discovered a new region of the magnetosphere, the invisible shield of magnetic fields and electrically charged particles that surround and protect Earth from the onslaught of the solar wind.

The northern and southern polar lights – aurora borealis and aurora australis – are the only parts of the magnetosphere that are visible, but it is a critical part of Earth's space environment.

"Although it is invisible, the magnetosphere has an impact on our everyday lives," Chappell said. "For example, solar storms agitate the magnetosphere in ways that can induce power surges in the electrical grid that trigger black outs, interfere with radio transmissions and mess up GPS signals. Charged particles in the magnetosphere can also damage the electronics in satellites and affect the temperature and motion of the upper atmosphere."

The other regions of the magnetosphere have been known for some time. Chappell and his colleagues pieced together a "natural cycle of energization" that accelerates the low-energy ions that originate from Earth's atmosphere up to the higher energy levels characteristic of the different regions in the magnetosphere.

The warm plasma cloak is a tenuous region that starts on the night side of the planet and wraps around the dayside but then gradually fades away on the afternoon side. As a result, it only reaches about three-quarters of the way around the planet. It is fed by low-energy charged particles that are lifted into space over Earth's poles, carried behind the Earth in its magnetic tail but then jerked around 180 degrees by a kink in the magnetic fields that boosts the particles back toward Earth in a region called the plasma sheet. link