Phew. Another year almost over and it’s been a really good one. This time last year, I was still blogging at WordPress, and it was only in late February that I beamed aboard the mighty ScienceBlog mothership. It’s been a great experience and all in all, I’ve managed to rack up about 190 posts on new research (excluding reposts and random stuff), over 1,500 comments and over 400,000 page views in a year. Elsewhere, I published a book based on this blog, I wrote about 2% of another book called “Defining Moments in Science“, and I wrote three features and several news pieces for New Scientist.
And given all that, it’s nice to take some time for reflection and with that in mind, I’m going to continue a tradition that I started last year – choosing some of the favourite stories from 2008. This list has no pretensions to be a catalogue of the year’s biggest stories or its most important breakthroughs. It’s just what I personally deemed to be the most interesting and just plain, downright cool.
So, without further ado, here are my picks. Once again, a massive thanks to anyone who read, commented on, or linked to this site over the last year. I hope you’ll join me for 2009.
In the twilit waters of the deep ocean, beneath about 1000m of water, swims the brownsnout spookfish (Dolichopteryx longipes). Like many other deep-sea fish, the spookfish is adapted to make the most of what little light penetrates to these depths, but it does so with some of the strangest eyes in the animal kingdom.
For a start, each eye is split into two connected parts, so the animal looks like it actually has four. One half points upwards and gives the spookfish a view of the ocean above. The other points downwards into the abyss below and it’s this half that makes the spookfish unique. The eyes of all other back-boned animals use a lens to divert the path of incoming light and focus it onto a specific point of the retina. But the spookfish’s downward-facing eye uses mirrors instead, forgoing a lens in favour of hundreds of tiny crystals that collect and focus light.
This bizarre animal was first described 120 years ago, but no one had discovered its reflective eyes until now because a live animal had never been caught. Hans-Joachim Wagner from Tubingen University changed all of that by netting a live specimen off the Pacific island of Tonga.
The spookfish’s eyes are similar in structure to many other fish that swim in the ocean’s twilight zone, where darkness is heavy but not quite total. The main part of each eye is tube-shaped and points to the surface, like a vertically mounted telescope. In photos A and B below, this upward-facing half has a yellow-orange shine because the camera’s flash has bounced off a reflective layer at the back of the eye.
On the fifth day of this year, I found myself sitting in the living room of the legendary Sir David Attenborough, drinking coffee and talking to him about wildlife, filmmaking and his career for the better part of an hour. It was a truly memorable experience, not just for his eloquence and storytelling skills, but because Sir David has been a hero of mine since I first popped Life on Earth into my VCR at the wee age of 8. His clarity and passion have inspired me to become a better communicator of science and it was a privilege to speak to the man in person.
He was no less of a superb raconteur in the flesh than he is on screen, and incredibly down-to-earth regarding his fame and status. His house was beautiful, furnsihed by the expected paintings of wildlife and tribal artifacts, a collection of beautiful fossils on a shelf behind his sofa, and more incongruously, an absolutely massive plasma-screen telly.
So now, as 2008 comes to close, I felt it fitting to repost the interview that began the year on such a high. It’s long, but Attenborough has so much that’s worth listening to. I hope you enjoy it as much as I did.
Solar power is a relatively new development for humans but, of course, many living things have been exploiting the power of the sun for millions of years, through the process of photosynthesis. This ability is usually limited to plants, algae and bacteria, but one unique animal can do it too – the emerald green sea slug Elysia chlorotica. This remarkable creature steals the genes and photosynthetic factories of a type of algae that it eats (Vaucheria littorea), so that it can independently draw energy from the sun. Through genetic thievery, it has become a solar-powered animal and a beautifully green one at that.
The cells of algae, like those of plants, contain small compartments called chloroplasts that are its engines of photosynthesis. As the Elysia munches on algae, it takes their chloroplasts into the cells of its own digestive system, where they provide it with energy and sugars. It’s a nifty trick that provides the sea slug with an extra energy source, but the problem is that it shouldn’t work.
Chloroplasts are not independent modules that can be easily separated from their host cell and implanted into another. They are the remnants of once-independent bacteria that formed such a strong alliance with the cells of ancient plants and algae, that they eventually lost their autonomy and became an integral part of their partner. In doing so, they transferred the majority of their own genes to their host so that today, chloroplasts only have a tiny and depleted genome of their own, containing just 10% of the genes it needs for a free-living existence.
So, shoving a chloroplast from an algal cell into an animal one should be about as effective as installing a piece of specialised Mac software on a PC. The two simply shouldn’t be compatible, and yet Elysia and its chloroplasts clearly are. Mary Rumpho from the University of Maine discovered the key to the partnership – the sea slug has also stolen vital genes from the algae that allows it to use the borrowed chloroplast. It has found a way to patch its own genome to make it photosynthesis-compatible.
As we communally slide ever further into drunkeness and obesity, I wish you all a very merry Christmas or a superlatively happy holiday, whichever you prefer. Best wishes to all of you and your families, friends and loved ones.
Over the next few days, I’ll stick up write-ups of a few cool studies that I missed out on when I was in Australia, a review of my favourite stuff of the year, a very special repost. And then on New Year’s Eve, it’s back on the road with new news with lots of punishment, hyperparasites, and genetic transfer.
Since the first living things appeared on the planet, the biggest among them have become increasingly bigger. Over 3.6 billion years of evolution, life’s maximum size has shot up by 16 orders of magnitude – about 10 quadrillion times – from single cells to the massive sequoias of today (below right). And no matter what people say, size does matter.
The largest of creatures, from the blue whale to the sauropod dinosaurs, are powerful captors of the imagination, but they are big draws for scientists too. Jonathan Payne from Stamford University is one of them, and together with a large team, he ambitiously set out to understand how the maximum size of living things has evolved throughout the entire history of life on Earth.
Taking each geological era and period in turn, the team scoured the literature for examples of the largest species alive at the time and recorded their size by volume. They also interviewed experts in the field of classification to get their side of the story. Payne’s full database is available online and it showed that the massive increase in life’s maximum size wasn’t a gradual process.
Instead, it happened in two main bursts, which took place in just 20% of the history of life but accounted for 75% of the increase in maximum size. On both occasions, the largest living things became about a million times larger. The first followed the evolution of more complex, compartmentalised cells and the second came after the advent of multi-celled creatures, and both coincided with dramatically rising levels of oxygen in the air. It was a case of environmental changes unlocking pre-existing evolutionary potential.
The relationship between bees and plants is one of the most well-known in the natural world. Almost everyone knows that bees carry pollen from plant to plant and receive a rewarding sip of sugary nectar in return. Surely there are few sides to this most familiar of alliances left to discover?
Not so. Jurgen Tautz and Michael Rostas from the University of Wuerzburg have found that bees provide another service to flowers, besides acting as a pollen vehicle – they deliver a protection service for their very buzzing scares away hungry caterpillars.
In their University’s botanical garden, they set up two cubic tents and placed either ten bell peppers or ten soybean plants inside them. On each plant, they added ten caterpillars of the beet armyworm – a voracious plant predator with catholic tastes in food. The only difference between the two tents was that one was connected to a beehive. Two feeders sat in the far corners of the tent, so that the workers regularly flew past the plants and the caterpillars on them.
After 18 days, Tautz and Rostas found that the plants which had been exposed to buzzing bees were far less damaged than the unprotected ones. For both soybeans and peppers, the caterpillars had damaged significant more leaves and gobbled over three times as much if there were no bees around. The only plants that weren’t protected by the bees were bell peppers that had already produced fruit – in those cases, the disturbed armyworms simply burrowed into the developing fruit, where they were safe from any potential threats.
The video above seems completely unremarkable at first – man walks down a corridor, navigating his way around easily visible and conspicuous obstacles. But it’s far from an easy task; in fact, it should be nigh-impossible. The man, known only as TN, is totally blind.
His inability to see stems from a failure in his brain rather than his eyes. Those work normally, but his visual cortex – the part of the brain that processes visual information – is inactive. As a result, TN is completely unaware of the ability to see and in his everyday life, he behaves like a blind person, using a stick to find his way around. Nevertheless, he can clearly make his way through a gauntlet of obstacles without making a single mistake.
TN was a doctor before two successive strokes destroyed his ability to see. The first one severely damaged the occipital lobe on the left side of his brain, which contains the visual cortex. About a month later, a second stroke took out the equivalent area on the right hemisphere. TN is one-of-a-kind, the only known patient with damage like this in the entire medical literature. The fibres that connect the occipital lobes on the right and left halves of the brain have also been severely damaged and tests reveal that no blood flows between these disconnected areas.