July 23, 2008
Category: Personal
Soooo....
When I started this blog, the intention was to try and use well-written articles on cool discoveries to get people who wouldn't normally read science blogs to be interested in science. I've now been writing for almost two years and while traffic has grown, it strikes me that I still don't know a lot about my readership, or the ratio of non-scientists/scientists who come to these pages.
So with that in mind, you can help me out by taking up these two challenges:
1) Tell me about you. Who are you? Do you have a background in science? If so, what draws you here as opposed to meatier, more academic fare? And if not, what brought you here and why have you stayed? Let loose with those comments.
2) Tell someone else about this blog and in particular, try and choose someone who's not a scientist but who you think might be interested in the type of stuff found in this blog. Ever had family members or groups of friends who've been giving you strange, pitying looks when you try to wax scientific on them? Send 'em here and let's see what they say.
Thanks folks. Game on.
E
Posted by Ed Yong at 10:52 AM • 31 Comments
July 22, 2008
Category: Animals • Conservation • Corals • Environment • Invertebrates
A complete ban on fishing can save coral reef communities in more ways than one. A few weeks ago, I blogged about a study which found that the coral trout, a victim of severe overfishing, was bouncing back in the small regions of the Great Barrier Reef where fishing has been totally forbidden. It certainly makes sense that fish will rebound when fishing ceases, but a new study reveals that the bans have had more indirect benefits - they have protected the corals from a predatory starfish.
The crown-of-thorns starfish (Acanthaster planci) is a voracious hunter of corals and a massive problem for reef conservationists. It's bad practice for any science writer to anthropomorphise an animal, but the crown-of-thorns really does look incredibly, well, evil. Its arms (and it can have as many as 20) are covered in sharp, venomous spines. As it crawls over the reef, it digests the underlying coral by extruding its stomach out through its underside.
From time to time, their numbers swell into plagues of thousands that leave behind the dead, white skeletons of corals in their wake. These outbreaks eventually die off as the starfish eat themselves out of food supplies, but not before seeding downstream reefs with their tiny larvae that drift along the southern currents. During their peak, they destroy far more coral than other disturbances such as bleaching events or hurricanes.
Now, Hugh Sweatman at the Australian Institute of Marine Science has found that these outbreaks are much less frequent in the "no-take marine reserves", where fishing is absolutely forbidden. Every year between 1994 and 2004, Sweatman carried out a census of starfish numbers in up to 137 areas across the Great Barrier Reef's massive length.
Read on »
Posted by Ed Yong at 5:46 PM • 0 Comments
July 21, 2008
Category: Animal behaviour • Animals • Cooperation • Invertebrates • Spiders
Social spiders are an arachnophobe's nightmare. While the vast majority of spiders work alone, the odd few live communally and cooperate to hunt and feed. Their numbers, along with the massive webs that they all have a spinneret in creating, allow them to tackle prey far larger than themselves. The aftermath of a kill opens up new conflicts for the spiders that other cooperating hunters like lions or wolves don't share. They don't divide up the carcass to eat separately, for like all spiders, they digest their prey outside their bodies.
All the colony members spit their digestive enzymes into the corpse and suck up the liquefied remains. But producing these enzymes costs energy, and since all the spiders are using the same opaque spittoon, there's no way for an individual to tell how much its teammates are coughing up. It's a system that favours cheats, who take their share of the communal resources but contribute very little toward creating them. This conflict isn't just theoretical - experiments have shown that groups of social spiders feed far less efficiently than individuals do.
In the face of this temptation to cheat, how do the spiders manage to eat anything at all? This is a perennial question faced by biologists who seek to understand the evolution of cooperation: why work together, when cheating often yields greater rewards? There are many possible answers and in the social spiders, Jutta Schneider and Trine Bilde saw a chance to test one of the most pervasive - the theory of kin selection.
Read on »
Posted by Ed Yong at 5:00 PM • 5 Comments
July 19, 2008
Category: Animal behaviour • Animals • Crustaceans • Invertebrates • Predators and prey
In April 1998, an aggressive creature named Tyson smashed through the quarter-inch-thick glass wall of his cell. He was soon subdued by nervous attendants and moved to a more secure facility in Great Yarmouth. Unlike his heavyweight namesake, Tyson was only four inches long. But scientists have recently found that Tyson, like all his kin, can throw one of the fastest and most powerful punches in nature. He was a mantis shrimp.
Mantis shrimps are aggressive relatives of crabs and lobsters and prey upon other animals by crippling them with devastating jabs. Their secret weapons are a pair of hinged arms folded away under their head, which they can unfurl at incredible speeds.
The 'spearer' species have arms ending in a fiendish barbed spike that they use to impale soft-bodied prey like fish. But the larger 'smasher' species have arms ending in heavy clubs, and use them to deliver blows with the same force as a rifle bullet.
Read on »
Posted by Ed Yong at 12:00 PM • 12 Comments
July 17, 2008
Category: Animal behaviour • Animal communication • Animals • Evolution • Fish • Neuroscience
New Scientist's Feedback section has a running series of items on "nominative determinism", that strange phenomenon where a person's bears eerie witness to their occupation, such as a neurologist called Lord Brain, or an article on urology authored by Splatt and Weedon. Well here's another example for them - a new paper about a singing fish from a scientist called Bass.
Beyond the wall-mounted horrors of Big Mouth Billy, fish are not exactly known for their vocal stylings, but one group - the toadfishes and midshipmans - are very noisy indeed. They make a range of dull grunts and hums by vibrating their swim bladder, the same organ that keeps them afloat.
In the Trials of Life, David Attenborough tells the story of an entire bay in America whose residents were infuriated by a bizarre throbbing noise that permeated their homes and drove them up the wall. The source was eventually discovered by a marine biologist, who played recordings through an underwater microphone and attracted female toadfishes in droves. It was the amorous males that were responsible, and their sexy songs were the cause of all the ruckus.
Now, Andrew Bass at Cornell University has shown that the tunes of these aquatic loudmouths are driven by a set of neurons that are shared by all vertebrates. This 'vocal motor nucleus' was most likely present in the last common ancestor of the entire group and evolved more than 400 million years ago. Since then, it has driven all manner of social communication, from the beautiful songs of birds, to the duller hums of toadfishes to the even more distressing warbling of the Spice Girls.
Read on »
Posted by Ed Yong at 2:00 PM • 2 Comments
July 16, 2008
Category: Genetics • Medicine & health • Obesity
Many measures to curb the obesity epidemic are aimed at young children. It's a sensible strategy - we know that overweight children have a good chance of becoming overweight adults. Family homes and schools have accordingly become critical arenas where the battle against the nation's growing waistlines is fought. But there is another equally important environment that can severely affect a person's chances of becoming overweight, but is more often overlooked - the womb.
Overweight parents tend to raise overweight children but over the last few years, studies have confirmed that this tendency to transcend generations isn't just the product of a shared home environment. Obesity-related genes are involved too, but even they aren't the whole story. Research has shown that a mother's bodyweight in the period during and just before pregnancy has a large influence on the future weight of her children.
For example, children born to mothers who have gone through drastic weight-loss surgery (where most of the stomach and intestine are bypassed) are half as likely to be obese themselves. On the other hand, mothers who put on weight between two pregnancies are more likely to have an obese second child. In this way, the obesity epidemic has the potential to trickle down through the generations, like a snowball rolling its way into an avalanche.
Now, Robert Waterland from the Baylor College of Medicine has demonstrated how the snowball gains momentum by studying three generations of mice that have a genetic tendency to overeat. And using a special diet that was high in folate and other nutrients, he found that he could stop the snowball's descent and spare future generations of mice from a heightened risk of obesity.
Read on »
Posted by Ed Yong at 2:00 PM • 8 Comments
July 15, 2008
Category: Brain • Memory • Perception • Psychology
Which of these strings of letters is easier to remember: QKJITJGPI or BBCITVCNN?
Chances are, you chose the latter string, where the nine letters are the combined names of three television networks. This neatly illustrates a fundamental property of human memory - that we remember long strings of information more easily if we can break them down into bite-sized chunks. In this case, a nine-letter string can be divided into three lots of three letters. You probably use similar strategies for remembering telephone numbers, credit card details, or post codes.
Now, Lisa Feigenson and Justin Halberda from Johns Hopkins University have found that infants just 14 months old can use the same technique, delightfully known as "chunking" to increase the limited scope of their memories. Their work suggests that this technique isn't something we learn through education or experience - it's more likely to be a basic part of the way our minds process information.
You can consciously use chunking to improve your recollection, but we all do it unconsciously to a large degree. In fact, the technique is the reason why we are rarely aware of the pitiful capacity of our working memory - the amount of information we can hold and work with for short periods of time.
For the longest time, psychologists believed that this mental workspace maxed out at seven items ; adults who saw a flashing array of letters or digits could only remember about seven at a time. But even this score is an overestimate. Later experiments which specifically set out to block chunking showed that adults can only store four items at most, while children and the elderly can only cope with three.
Read on »
Posted by Ed Yong at 8:33 AM • 8 Comments
July 14, 2008
Category: Animals • Cancer • Evolution • Life history • Mammals • Medicine & health
Evolution dances to the tune of death. Killers - be they predators, diseases or competitive peers - can radically shape a species' life cycles by striking down individuals of a certain age. The survivors respond by changing their "life histories" - a collection of traits that defines their reproductive cycles, including how often they breed, when they start to do so and how many young they have.
If an animal's adult life is short and brutal, they tend to grow quickly and become sexually mature at a young age - a strategy that maximises their chances of siring the next generation. The Tasmanian devil may be the latest species to switch to this live-fast, die-young tactic, for their adult population is slowly being wiped off by a contagious cancer.
I've blogged about the disease before. Known as devil facial tumour disease (DFTD), it was first reported in 1996, when devils first started appearing with horrendous facial tumours. Since then, it has spread across half of the devil's home range and has cut a swathe through its populations. Hamish McCallum at the University of Tasmania calculated that the disease, if left unchecked, could drive the Tasmanian devil to extinction within 20-25 years.
But amazingly enough, the devils have started to adapt. So fatal is the disease to adults that the devil population is getting younger and younger and Menna Jones, a colleague of McCallum's, has found that they are starting to reproduce at a much earlier age too. The surviving devils are in a race against time to reproduce before the cancer kills them off.
Read on »
Posted by Ed Yong at 5:00 PM • 2 Comments
July 12, 2008
Category: Animal behaviour • Animal locomotion • Animals • Invertebrates • Spiders
There is an old joke that if Spider-Man has the powers of a spider, he really ought to be shooting webs from somewhere less salubrious than his hands. In the films and comic books, Peter Parker is empowered with the powers of a human-sized arachnid through a spider bite. He effortlessly scales walls and ceilings and shoots sticky webs from his wrists. Now, scientists have found a type of spider that does just that.
Like Spider-Man, most spiders can climb sheer surfaces and they do so with two techniques. The most obvious are small claws, called tarsi, that grip onto rough surfaces. Going down in scale, their feet also end in thousands of tiny hairs. These hairs make such close contacts with the microscopic troughs and crests of seemingly smooth surfaces that they stick using the same forces that hold individual molecules together.
But Stanislav Gorb and colleagues from the Max Planck Institute have found that one species of spider uses a third method, which exploits that most characteristic of spider traits - silk. All spider species spin silk from appropriately named organs on their rear ends called spinnerets. But uniquely to spiders, the Costa Rican zebra tarantula (Aphonopelma seemanni) from spins silk from its feet as well.
Read on »
Posted by Ed Yong at 12:00 PM • 5 Comments
LOLbachia
