Archives for January 2009

When Sir David Attenborough announced last year that Life in Cold Blood would be his last major TV series, somehow you knew it wouldn't be the last we'd see of natural history's dominant silverback.

Well, now 82-year-old Sir David is back and - if anything - feistier than ever.

Watching Charles Darwin and the Tree of Life you get the impression that "retirement" has been good for him. After a career spent studiously compiling and presenting the evidence, Sir David seems to have shaken off the straightjacket of scholarly impartiality. Finally we get to hear what he really thinks.

It's strong stuff. Like the invasion of England by William the Conqueror, evolution is a fact - if anything it's better supported by the evidence, because there's so much more of it.

"Above all Darwin has shown us that we are not apart from the natural world - we do not have dominion over it," Sir David says. "We are subject to its laws and processes as are all the other animals on earth to which indeed we are related."

One by one, and using a fair amount of archive footage featuring a familiar - if somewhat younger - presenter, Sir David demolishes the arguments employed to refute Darwin's theory with his usual headmasterly charm.

It's a powerful piece of film making, and you get the impression that only a figure of such stature in the world of natural history could do it justice. Perhaps they should have called it Attenborough on Darwin and left it at that.

It's been a busy week on the programme, but I was struck by Lord Drayson's point that science may be too "elitist".

Science can certainly be hard - as I learnt trying to get my head round the basics of particle physics in the run up to the launch of the Large Hadron Collider last year.

Years ago I remember the neurologist turned arts impresario Sir Jonathan Miller admit that the ideas he'd had to grapple with as a scientist had "made his head hurt" in a way that the theatre never had, and it's true that the complexity of some ideas in science can act as a barrier making the subject fairly inaccessible.

But that's a very meritocratic kind of exclusivity....it doesn't matter where you were born, you just have to be clever.

Of course the point the science minister was making is about the image of science, and of scientists, as "nerdy" and somehow detached from everyday life. A government campaign to excite people about science and the opportunities it can create is surely welcome.

One area of science that doesn't need any help drumming up excitement is geo-engineering - the idea that we might solve global warming by managing the climate on a planetary scale.

A whole raft of apparently hair-brained schemes - from seeding the oceans with iron to building giant sun shades in space - have been suggested, but no one seems to know which ones might work or how much they'd cost.

Now scientists at the University of East Anglia have conducted the first comprehensive assessment of 20 of the leading geo-engineering solutions to climate change, trying to work out how much cooling you might get, and how feasible they really are.

It turns out that stratospheric aerosol injections - spraying sulphates into the upper atmosphere - has the greatest potential to cool the climate quickly, but doesn't address the longer term consequences of continuing to burn CO2. Professor Tim Lenton suggested that increasing the capacity of carbon sinks - locking greenhouse gases away in biomass or on the ocean floor - might be a better long term solution.

None of which will do anything to stem the decline of the honeybee.

Scientists remain baffled by the mysterious disappearing act of whole populations - named Colony Collapse Disorder in the US and Canada, and which now seems to have spread to Italy, France and Germany.

Here a succession of cold winters and wet summers has reduced honeybee numbers by about 30%, and even Jill Archer seems to be having trouble with the virtual bees of Ambridge.

But help may be at hand: Britain's biggest farmer, the Co-op, launched a ten-point rescue plan this week which included a ban on the use of eight neonicotinoid pesticides and £150,000 for research.

Interestingly the Co-op's Paul Monaghan told me they can't find any takers for the research money to investigate honeybee decline. So get busy with that grant proposal.

It's official: there's no place left on earth to hide from global warming.

Until today it had been thought that a large part of the Antarctic continent - the East Antarctic Ice Sheet - had actually been cooling while the rest of the planet warmed up - bucking the trend of climate change.

That view was given the official stamp of scientific opinion in 2007 when the IPCC (the Inter-Governmental Panel on Climate Change) concluded there had been "significant anthropogenic warming over the past 50 years averaged over each continent....except Antarctica".

But it seems this caveat had more to do with a lack of data than a lack of warming. A paper published in the journal Nature today argues that overall the continent has been warming at a rate comparable to the rest of the world.

The confusion stems from the fact that the majority of weather stations on Antarctica are based along the coast. In fact, there are only two stations in the continent's vast, inhospitable interior (an area bigger than western Europe) that have been supplying reliable data over the last 50 years.

It was the results from these two stations that - although statistically insignificant - had given rise to the idea that the central continental mass was cooling.

The latest study, led by professor Eric Steig at the University of Washington in Seattle, uses a combination of ground based measurements and satellite data to construct a new, and - he argues - more robust picture of temperature trends.

The researchers found that temperatures had risen dramatically along the Antarctic Peninsular and the West Antarctic Ice Sheet, but much more modestly across East Antarctica. Overall average temperature had risen 0.5 degrees in the last 50 years, correlating closely with the global average of 0.6 degrees.

It's bad news for climate change sceptics who have highlighted the anomaly of the world's coldest continent apparently getting even colder as a significant flaw in the global warming narrative. But of course it would also be bad news for everyone else.

A warming Antarctica completes the set. The evidence from all seven of the continental land masses now seems to point in the same direction.

Scientists studying bugs in the lowland rainforests of Peru have discovered a dung beetle with a difference.

This dung beetle, a well known species named Deltochilum Valgum, appears to have given up eating dung altogether and decided to eat the millipedes that live along side it instead - and it really is a voracious predator, using its hind legs to latch onto much larger millipedes, decapitating them, and eating them from the inside out.

Observing the beetle's bizarre behaviour in pitfall traps the team, led by Dr Trond Larsen from Princeton University, realised that subtle changes in the shape of its head and hind limbs had enabled this dung beetle to abandon traditional ball-rolling behaviour and make the leap to predation.

In subsequent tests, and using a variety of paired dung and millipede baits, Deltochilum Valgum "was attracted exclusively to millipedes, and strongly preferred live injured millipedes over dead millipedes."

Writing in the Royal Society Journal Biology Letters Dr Larsen argues that intense competition amongst dung beetles (which occupy a highly specialised ecological niche) could be promoting speciation - the process by which one species evolves into something new.

"Ecological transitions such as these are important for understanding the evolution and diversification of new species and may help explain the disproportionately high diversity of insects".

It's a rare snapshot of evolution caught in the act. We may be witnessing the birth of a new species...the millipede predator beetle.

Great ideas don't simply pop into existence all at once, and although 2009 marks the 150th anniversary of Charles Darwin's On the Origin of Species, the development of the theory of evolution can be traced back over two centuries of natural history.

Darwin himself built on the pioneering work of earlier explorers and naturalists - men like Alexander von Humbolt, whose adventures in Mexico and south America demonstrated how little was known or understood about the world beyond Europe at the turn of the 19th Century.

In turn, his "dangerous idea" inspired subsequent generations to brave hardship and deprivation in a bid to test and shape the theory.

The American geneticist Sean B Carroll charts the evolution of this revolution in Remarkable Creatures: Epic Adventures in the Search for the Origin of Species.

And a swashbuckling tale of derring-do it is. From Eugene Dubois' 30 year search for the missing link to Roy Chapman Andrews' staggering fossil hauls in the badlands of the Gobi desert, Prof Carroll tells the story of life on earth's three billion year history through the adventures and discoveries of the men and women who helped uncover it.

Having mined the fossil and historical records Carroll turns to the present, bringing this epic story up to date in the genetics laboratories - like his own at the University of Wisconsin-Madison - that have delved into the DNA record of life.

But what of the future? Perhaps the most important question - certainly the most exciting prospect - facing science today concerns the search for extra-terrestrial life. And if, or when, we find it Sean Carroll concludes, we'll realise Darwin has beat us to it. The theory of evolution by natural selection is truly universal.

As ecologists have discovered to their cost it isn't the mice you have to worry about...it's the rabbits.

Removing cats from the sub-Antarctic island of Macquarie, a World Heritage Site valued for it's complex tundra habitat and unique geological formations, probably seemed like a good idea at the time.

It's not hard to imagine how the argument ran: As an invasive alien species - and voracious predator - the cat (which was probably introduced inadvertently by sailors around the turn of the 19th century) was inevitably exerting a dramatic influence over the natural ecosystem. Removing it would allow the native flora and fauna to recover to something like their original state. QED the cats had to go, and an eradication programme began in 1985.

The last cat was killed in 2000, but far from resulting in the anticipated renaissance for native species, the outcome has been an unmitigated ecological disaster.

According to a study published in the Journal of Applied Ecology the eradication programme has caused an environmental catastrophe that will cost more than £11 million to put right. The study shows that between 2000 and 2007 widespread ecosystem devastation took place and substantial damage at both local and landscape scales had "compromised decades of conservation effort".

Some clue as to what went wrong comes from a closer analysis of those changes: "Complex vegetation communities..." had been reduced to "...short, grazed lawns or bare ground".

The culprit is the rabbit. Ironically another non-native species originally introduced by sealing gangs in 1878 to provide a ready supply of food. It turns out that the cats had been keeping the rabbit population at bay. Free of the pressure of predation the rabbits had done what rabbits do, and by the end of the survey period their numbers had mushroomed to over a hundred thousand individuals.

It's a classic example of what ecologists call a "trophic cascade" - the devastating knock-on effect that changes in the abundance of one species can have across several links in the food chain. And as the report's authors note, it's a sobering lesson for conservationists interested in preserving native ecosystems from invasive aliens.

So what now for plans to eradicate Japanese knotweed, Chinese mitten crabs or the American crayfish from British habitats?

"It would be like having a fire engine or an ambulance ready and waiting on every street corner".

This is how Dr Sara Rankin describes the enormous potential of a ground-breaking new technique scientists at Imperial College London have developed to dramatically enhance the body's ability to repair itself.

Using a combination of drugs the team has stimulated bone marrow into releasing a flood of adult stem cells into the bloodstream. These then hurry to the site of an injury in the body to begin the process of repair and regenerate tissue.

Unlike existing adult stem cell therapies - which involve extracting stem cells from the bone marrow and processing them in the laboratory with growth factors before they can be re-implanted at the site of an injury - the new technique is completely non-invasive. In theory it could mean the healing process would begin more quickly, leading to a more complete recovery.

The study, published in the American journal Cell Stem Cell, also managed to stimulate the development of a wider range of stem cell types, meaning that the technique could be used to regenerate soft tissues like heart muscle or liver, as well as bone and cartilage.

This additional flexibility raises the prospect that adult stem cells could one day replace those derived from human embryos in the development of new treatments.

Until recently much of the research effort in the field has focused on embryonic stem cells because of their increased pluripotency - they have the potential to develop into almost all of the 200 cell types in the body. But if adult stem cells prove to be as malleable, Dr Rankin believes, it might be possible to avoid the ethical dilemmas associated with embryonic stem cells.

Although he welcomed the research, and acknowledged other recent advances (particularly in cell reprogramming), Cambridge University's Professor Roger Pedersen says it's too soon to think about abandoning embryonic research.

Not least because it provided the vital theoretical framework which had allowed these developments to take place.

"We need the best brains working on the best brains." That's the way Professor Paul Francis from King's College London sums up the problem facing scientists working on a range of diseases including Alzheimer's, Parkinson's and Autism.

The simple fact, he says, is that not enough people are donating their brains to medical science after they die - and if that doesn't change vital research into the neurological processes that cause these diseases could grind to a halt.

Academics like professor Francis say they need some 300 people a year to donate their brains to help find cures and treatments for Alzheimer's, but nothing like that number are coming forward.

At the Oxford Brain Bank for Autism researchers have just 20 brains to work on - no where near enough to draw meaningful scientific conclusions from comparisons with healthy tissue.

Ironically the shortage of healthy brains to run comparisons with is even more acute, and scientists are urging people who don't suffer from any sort of neurological condition to consider leaving their brains to medical science.

Part of the problem, according to Professor Margaret Esiri at the University of Oxford, may be that people are reluctant to donate their brains because they see the organ as the basis of their identity. "It used to be other parts of the body that we thought were important but now people realise that their brain is the crucial thing that gives them their mind and their self."

It's this area of neurological research - into consciousness and developing a 'theory of the brain' - that really excites Professor Steven Rose. Speaking on the programme this morning he described neuroscience as the hottest area of research in biology.

"You and I have a hundred billion nerve cells in our brain, with a hundred trillion connections between them. The possible permutations of those connections are more than there are particles in the universe. It's clear that we cannot understand the brain of any of us, or certainly the minds of any of us, without putting neuroscience together in a much broader context than many of us are able to think about."