Day: February 6, 2010

In Ages Long Ago II…

Nick Lane is a prolific writer and has some very interesting pieces available at “New Scientist” as well as his own web-pages. Very readable work from a biochemist. Here’s a sampler from “New Scientist”…

The Big O …not orgasm, but Oxygen and its variations through geological time. During the Carboniferous it was 35% of the atmosphere (just 21% today), yet a few million years later it was just 12% at the end of the Permian. How did Life respond?

Has the mystery of sex been explained at last? …why do we have sex when some animals get along without it just fine? Or do they? The old explanation is that sex helps defend against external parasites… BUT that doesn’t quite work. What about genomic ‘parasites’?

What’s the point of being warm-blooded? …maintaining a high, constant body temperature is what burns most of our calories in a day, and that’s true for almost all mammals and birds. Why the waste heat? Why not burn slower like our reptilian ancestors?

Was our oldest ancestor a proton-powered rock? …Think ‘Chemiosmosis’ and you’ll get the idea. The LUCA (Last Universal Common Ancestor) was a cell in a ‘rock’… read more for details and an engrossingly told story. A summary in 10 Steps is available too.

Finally, not from Nick Lane, is this ABC News item…

Cell’s Power Packs Came from Within

…which studies how mitochondria – the common energy factory of all eukaryotes – came to be converted from a free-living bacterium to energy centre. Apparently the transfer molecular machinery that shuttles materials from mitochondrion to host cell came together from diverse bacterial parts organised in those first eukaryotes, and the researchers recreated just how.

In Ages Long Ago…

Not the opener to “Voltron”, but the latest synthetic palaeo-news.

First, appropriately enough, the first tracks of the First Crawling Things…

Found: The first ever animal trails …reported by “New Scientist”, some rock-hounds have discovered 565 million year old anemone trails. Well… they look like anemone trails at least. Older ‘trackways’ are known, but they’re not obviously animal tracks since things like gas-bubbles under algal mats can leave similar markings. These are the real deal.

But why then? The Ediacaran/Vendian came just after the last Big Glaciation (Snowball Earth) and a multitude of squishy, shelly Things appeared and left fossils. Why not earlier?

The next news item answers that…

First breath: Earth’s billion-year struggle for oxygen …seems cyanobacteria, the oxygen-making variety, didn’t appear until c.2.7 billion years ago, took 300 myr to oxygenate the air, then collapsed during the subsequent Ice Age, caused by oxidation of the methane greenhouse of the time. The first series case of climate change due to Life’s by-products, perhaps. An earlier one might’ve been caused by the methanogens themselves, who warmed the Archean Earth.

After the end Archean Ice Age, the Earth languished in an epoch of smelly oceans – hydrogen sulphide and sulfate dominated – but finally something shifted, probably the Greening of Rodinia about 800 mya. This mass erosion event caused by lichens and terrestrial algaes, set the Earth for the Snowball Earth events and the subsequent explosion of animal Life. Or so the story goes as told by Nick Lane. Like all such Proterozoic Tales, there’s a lot we just don’t know.

The implications are interesting. Where did the oxygen making bacteria come from? Could they have drifted in from Venus as its oceans were wafted into the stratosphere and photolysed? That’s my pet theory – we’re all Venusians. Of course Panspermia implies all the suitable solar planets and moons are really one common biosphere.

Pluto and Beyond…

Marc Buie, Pluto guru, has spent several years of computer time – or scrapings of time over several years – to process observations of Pluto done with the HST…

Unusually Rapid Changes on Pluto

…reported with panache, by Paul Gilster at Centauri Dreams and all over the web. Pluto has rather dramatic seasons it seems. And, c.14 July 2015 we’ll know a lot more as “New Horizons” flings past at very high speed, snapping at a resolution of ~100 metres (i.e. really HIGH.) While chasing this news item I ran into a very handy web-page…

New Horizons Real-Time Simulation

…which gives a live countdown to arrival and a count-up from Launch, plus positional data. A companion page is here…

Spacecraft Leaving Our Solar System

…with similar data for “Voyager” 1 & 2 and “Pioneer” 10 & 11 on display. Our first Interstellar probes, “Voyager” 1 & 2 are expected to be signalling until 2025 or so. Maybe 2027… the first 50 year Mission?