Features

I really enjoyed this article in New Scientist about Lagrangian points - 'dead zones' in the solar system where opposing forces cancel out gravity and all kinds of items from cosmic dust to asteroids may accumulate becalmed.

NASA's twin STEREO probes, that were launched in 2006 to observe the Sun, are now being tasked to spy on two of these enigmatic spaces on the way to their final destinations (one orbiting ahead of the Earth and the other in its wake).

It's a great example of the serendipitous component to a lot of science: as one of the STEREO lead researchers explains the probes were never designed to look for asteroids (they're actually looking for solar storms) but now they have a golden opportunity to go rock-spotting.

I think the role of serendipity, especially in areas such as space and big science facilities where project lead times are so long, is something that doesn't get talked about enough. It's part of the invisible web that joins up different areas of science and ensures that a new instrument or technical advance in one area can create spin-off benefits for research into something very different. 

There's a nice Oxford link to STEREO that I'll be blogging about in detail later in the year. 

Today saw the launch of Galaxy Zoo 2: the project that enables web users to contribute to research into galaxies and how they evolve.

This report from BBC Breakfast's Graham Satchell gives an excellent overview of the project and includes an interview with one of Galaxy Zoo's founders, Oxford's Chris Lintott as well as just a few of the galaxy-spotting volunteers [nicknamed 'Zooites'] who have helped make the project such a success.

First reports are that GZ2's servers are buzzing with ten times the traffic of the original GZ launch: no doubt helped by the fact that Graham's report is linked from the front page of the entire BBC website! Chris's appearance on The Today Programme this morning can't have hurt either. 

Galactic mergers - cosmic 'train wrecks' in which galaxies collide - are one of the things that the GZ2 team hope users visiting the site can help them describe in detail. One of the discussions we had whilst putting the release together was whether mergers could be described as 'odd' or 'unusual' - although there was agreement that they are rare. 

Interestingly, as part of looking into this, I stumbled across this New Scientist piece that reports on research into how, in less than two billion years, our own galaxy - the Milky Way - will in fact merge with our neighbour the Andromeda galaxy: these two galaxies are currently rushing towards each other at 120 kilometres per second.

New Scientist's Hazel Muir writes: 'The scientists watched how gravity choreographed the motions of the two galaxies up to 10 billion years into the future. The results suggest they will pass close to each other in less than 2 billion years, well within the Sun's lifetime. At this point, their mutual gravity would start to mess up their structures and tug out long tails of stars and gas.'

'The two galaxies would then overshoot and come together again for a second close passage before finally merging about 5 billion years from now. The merged galaxy, which [the researcher] dubs Milkomeda, will be a blobby elliptical galaxy, rather than a neat spiral like Andromeda or the Milky Way today.'

Perhaps we should all visit GZ2 to find out what a merger looks like, just in case we're around in two billion years' time to watch... 

All this week we're celebrating Darwin and the advances in evolutionary theory that have built upon his work.

From The Beagle to the beard Charles Darwin and his world seem rather distant from our lives today: little wonder perhaps, as so much has changed in 200 years.

But how does Darwin match up to the 21st Century scientist? This is one of the intriguing questions Paul Harvey of Oxford's Department of Zoology addresses in an article to appear in the Journal of Biology.

He argues that Darwin posed many of the same sorts of questions as  biologists working today. 'He set the research agenda that many still follow: as Dobzhansky famously put it “nothing in Biology makes sense except in the light of evolution”.'

As Paul comments he could not have known how to pursue the great unknowns in genetics, or how developmental biology would be incorporated into mainstream evolutionary theory 'But he did frame many of the unsolved questions for what we would now call organismic biology.'

'He appreciated the importance of sexual selection, that something generally kept sex ratios around 50:50, that altruism must evolve by some interesting process, that distastefulness and warning colouration are in some sense adaptations. He didn't exactly know how these things evolved, and even explicitly left some problems to be solved in the future.'

Darwin may have needed others to come up with the elegant algebra to identify what would evolve as conditions changed 'But, as a 21st Century scientist, his correspondents would have included some theoreticians who could better develop his ideas and force him to state his assumptions with greater clarity.'

In other ways, however, Darwin was a scientist of his time: who, in a more gentlemanly age of scientific reporting which did not give so much weight to publishing first, was determined to reflect at length and not rush out his results.

'Indeed, he went further and argued that his career had taught him that there had not been an example when he has regretted holding back on publication,' Paul notes. 'The published product, he argued, was all the better for repeated polishing and tinkering. That is virtually unthinkable nowadays, with so many Wallace orthologues in the woodwork. The balance has shifted increasingly towards achieving priority.'

Here was a scientist who got better with age or perhaps whose thought processes hardly seemed to age at all: 'there's no doubt in my mind that he could have kept on going for another lifetime - once you have set the conceptual foundation as he did, then the world opens up for you... We have to remind ourselves that, while Darwin was always learning, if he felt that a gradual accumulation of facts questioned a treasured conclusion, then he would revisit that conclusion and all that resulted from it.'

Professor Paul Harvey is Head of Oxford's Department of Zoology.

Read more of our Darwin special: worms & vertebrates, humanity's roots, birds, beaks & species, virus wars

All this week we're celebrating Darwin and the advances in evolutionary theory that have built upon his work.

I asked Aris Katzourakis of Oxford's Department of Zoology about the evolutionary 'arms race' between viruses and us:

OxSciBlog: How does studying virus evolution compare to studying the evolution of larger organisms?
Aris Katzourakis: Virus evolution occurs over far shorter time frames, and can be observed on the molecular level. For example, for rapidly evolving RNA viruses like HIV or Hepatitis C, evolution can be observed during the course of an infection within a single patient, while for the Influenza virus, evolution can be observed within the human population over the years. This offers unique opportunities to study evolution in real time, while also enabling predictions about the course of viral evolution that can be applied in a public health setting.

OSB: What makes the evolution of viruses such as lentiviruses and HIV/AIDS so challenging to unravel?
AK: The lentiviruses are locked in an arms race with the immune systems of their hosts, meaning that both parties are constantly changing in order to adapt to new challenges. This effect has been called the ‘Red Queen’ effect in evolutionary biology, in reference to the statement by the character of the same new, from Lewis Carroll's book - “It takes all the running you can do, to keep in the same place”. In practical terms, this means that the genomes of lentiviruses are constantly changing, and we are still a long way from unravelling all the pressures exerted upon the virus by the immune systems of their mammalian hosts.

OSB: What does research into lentiviruses suggest about their possible future evolution and that of HIV/AIDS?
AK: Recent research from studies of endogenous lentiviruses has shown that the lentiviruses are far older and more widespread among mammals than has been previously appreciated. This implies that there may be more lentiviruses that remain undiscovered in the wild, that could potentially make the leap from infecting other mammals to infecting people. Furthermore, the realization that lentiviruses are millions of years old implies that the corresponding conflict with their hosts immune systems has been played out over this period of time. Perhaps there remain undiscovered host innate immune factors in mammalian species, resulting from this ancient conflict, that could be harnessed in the fight against HIV.

OSB: What technological advances on the horizon could transform studies of virus evolution?
AK: Ever cheaper and more rapid sequencing will undoubtedly greatly expand our knowledge of virus evolution. Coupled with this, advances in computational techniques required to make sense of this data will prove instrumental. Many exciting discoveries in virology have occurred from the most unexpected places - I suspect the most important findings of the coming years will come as a surprise to researchers in the field of virus evolution.

Dr Aris Katzourakis is based at the Department of Zoology and the Institute for Emergent Infections, James Martin 21st Century School.

Read more of our Darwin special: worms & vertebrates, humanity's roots, birds, beaks & species

All this week we're celebrating Darwin and the advances in evolutionary theory that have built upon his work.

I asked Joseph Tobias of Oxford's Department of Zoology about birds, their traits, and how they evolved:

OxSciBlog: Darwin was fascinated by finches: What is it about birds that makes them ideal case studies for evolution?
Joseph Tobias: Viewpoints differ, as always. One regularly hears that birds are not ideal systems for evolutionary research. Listen to any entomologist or bacteriologist, for example, and they will tell you that birds are too much work to keep in the lab, or too slow to reproduce. A botanist will add that wild birds wake up impossibly early and move around too much. An ornithologist, however, will point out that birds make rewarding subjects because they can be studied in natural settings, and they offer several key measurable traits.

Some of these traits - including the number of eggs produced in a clutch - are associated with life-history, while others are linked to ecology. The beak, for example, is the main foraging apparatus of birds, and therefore strongly shaped by diet. Variation in beak design is a feature of adaptive radiations, as was evident in Darwin’s collection of finch specimens from the Galápagos, thus providing an inspiration for the theory of natural selection. Similarly, elaborate plumage ornaments and complex songs were central to the development of Darwin’s 'other theory', sexual selection.

Beaks, plumes and songs continue to be mainstays of evolutionary research. Meanwhile, birds have also made a disproportionate contribution to our understanding of behaviour as an agent of selection, partly because wild birds are easier to catch, mark, track and observe than many other animals.

To some extent, the role of ornithology as a driving force within evolutionary biology can be boiled down to the fact that birds, like us, are audio-visual creatures with acute colour vision and mid-range hearing. From a signalling perspective, they speak our language, and this explains a large part of their allure.

OSB: What can birds tell us about Darwin's 'mystery of mysteries', the origin of species?
JT: One upshot of the popularity of birds is that we know lots about them, and this simple fact accentuates their importance for studies of speciation. We have at our disposal more information about species limits, global ranges, ecological niches, and life-history strategies for birds than for any other diverse group of animals or plants. The same can be said of sequence data, as a flood of phylogenetic studies is rapidly filling out the avian tree of life. Given that the molecular clock is relatively consistent in birds, biologists can use these sequence data not only to determine the relationships between the branches of the tree but to estimate the timing of evolutionary events, including speciation. By putting these resources together, and applying increasingly powerful computational methods, it is becoming possible to test previously intractable hypotheses about the factors promoting reproductive isolation and shaping patterns of diversity.

Genetic data have already taught us more in the past decade about the way lineages diversify than we learned in the other 190 years since the birth of Darwin. The good news is that this exhilarating period of discovery is set to continue, with birds as a common theme.

OSB: What have your studies of Amazonian birds revealed about the evolution of signals?
JT: Most Amazonian birds have simple, genetically determined songs. By quantifying their structure, and conducting experiments to test perception, we are investigating how these signals are shaped by ecology and interactions.

For example, we have found that songs of different species are adapted to the transmission properties and noise regimes of their respective microhabitats. Whether by this kind of ecological adaptation or by random mutation, the process of signal divergence in isolated forest patches can be fairly rapid: a few thousand years can produce enough difference in song structure to reduce responses between populations. On the other hand, we have found compelling evidence that interspecific competition can drive convergence in territorial songs, suggesting that social selection can operate across species boundaries.

Further work on dueting species has shown that temporal coordination in joint signals is promoted by intersexual conflict rather than, as commonly assumed, cooperation. These are a few examples of how a comparative and experimental approach can clarify the mechanisms underlying speciation and phenotypic evolution.

OSB: How might research into evolution help in the conservation of rain-forest species?
JT: Some apparent flaws in current conservation practice can be attributed to a species-based mentality. This means that, in deciding what we want to conserve, we use as our currency a system of units that represent a mere snapshot of evolution, and which in any case we find impossible to define. Of course there will always be powerful flagship causes like pandas and whales, but evolutionary biology and conservation genetics can expand our consciousness beyond the ‘species’.

These disciplines encourage a consideration of the longer view, and of process rather than pattern. They highlight the importance, for example, of connectivity between habitats rather than isolated reserves. They reveal the remarkable genetic diversification within rainforest ‘species’, and draw attention to zones of future evolutionary potential. The pattern-based view directs resources towards the conservation of island faunas, where populations are naturally rare and often short-lived, whereas the evolutionary view argues for the re-direction of some of those resources to continental habitats, and to rainforests in particular. These are the powerhouses of terrestrial evolution, but they will only continue to function as such if we succeed in maintaining them at something like their present size.

Dr Joseph Tobias is a Departmental Lecturer in Evolutionary Ecology at Oxford’s Department of Zoology.

Read more of our Darwin special: worms & vertebrates, humanity's roots