Paul Barrett is the 2011 recipient of the Bicentenary Medal of the Linnean Society, an organisation that promotes all branches of natural history, including botany and zoology.

Paul does research on dinosaurs but is also heavily involved in working with public audiences through exhibitions, media and other routes.

The medal is awarded annually in recognition of work done by a biologist under the age of 40 years, and it was first awarded in 1978 on the 200th anniversary of the death of Carl Linnaeus. The award was presented at the Linnean Society anniversary meeting in Burlington House, London, in May.

How do new species form?  One key process is by genetic divergence following geographical isolation – allopatric speciation.  This can happen when different populations of a single species are separated, cease to have contact over time and no longer interbreed.  This separation, divergence and formation of new species will often be attributed to changes in genetic makeup as a result of adaptation to different environments or ecosystems, or simply to accumulated genetic changes - genetic drift.

When it's difficult for individuals from the population to cross geographical barriers, it's possible to explain how isolation of populations occurs, and therefore why speciation has happened. An example would be the different but related species found on islands separated from the mainland, where a few individuals managed to cross the water barrier and form a new population that eventually became a distinct new species.  Charles Darwin collected specimens of mockingbirds on the Galapagos, for example, that are related to mainland species but which have diverged from the parent population to become a separate species, living in a new and different environment.

In the sea, however, many animals have pelagic larvae – free-floating planktonic forms - that can be carried for many hundreds of kilometres in currents, even though the adults have limited mobility on the sea bed.  This pelagic mobility means that closely related species from different places are potentially connected over distances of 1,000 km or more, so it is unclear how allopatric speciation is achieved – the populations appear to be capable of connection in geographical terms.

Zoology PhD student Martine Claremont, together with her Museum supervisors Drs Suzanne Williams and David Reid, and university supervisor Professor Tim Barraclough, sampled populations of the intertidal muricid gastropod genus Stramonita (a marine snail) throughout the Atlantic Ocean and used statistical analysis of DNA sequences to identify the number of distinct species, their distributions and relationships.

For species in which the larvae spend only a short time in the plankton, it is possible for populations to be clearly isolated geographically by currents, island chains or other factors such as the immense flow of fresh water flowing from the mouth of the Amazon. However, Stramonita spends 2-3 months as a planktonic larval form, theoretically permitting genetic contact across the entire ocean basin, which might lead to expectations that a single population would be found around the Atlantic. 

Stramonita brasiliensis, the new species described in the work (E, Plymouth, Tobago, BMNH acc. no. 2341; F, holotype, Sao Paulo, Brazil, BMNH 20100324)

However, Martine and her supervisors found five distinct species in the Atlantic (one of which is described as new).  They suggest that this speciation might be attributed in part to past changes or interruptions in ocean currents, preventing free circulation and isolating populations for sufficient time to enable speciation.  Other factors that seem to be of importance are the ancient separation of the Caribbean and Gulf of Mexico and the development of ecological specialization.

Claremont, M., Williams, S.T., Barraclough, T.G., Reid, D.G. (2011) The geographic scale of speciation in a marine snail with high dispersal potential. Journal of Biogeography, 38: 1016–1032.

Are we in the middle of a 6th mass extinction event or losing 100 species a day?
An entomology departmental seminar

2 June 2011

11:30 - 12:30

Neil Chalmers Seminar Room, DC2

Professor Nigel E. Stork
Head of Department of Resource Management and Geography,
Melbourne School of Land and Environment,
Melbourne University
Australia

Nigel Stork worked in the Entomology Department of the Museum from 1980 to 1995 before taking on the role of managing Australia's national research centre on tropical forest management. His experiences from working in the Museum and elsewhere have lead him to question some of the conclusions that have been made about the current state of biodiversity. Biologists have been predicting species losses of 100 a day for more than 30 years and many suggest that we are in the midst of a 6th mass extinction event. In this talk Prof Stork reviews just how much (or rather how little) we know about the size of global diversity and about species extinction rates. Since 'to the nearest approximation all species are insects' he will focus some of his attention on understanding invertebrate diversity and particularly that in tropical forests.

For further information see http://www.nhm.ac.uk/research-curation/seminars-events/index.html

Dr Tom Richards and postdoctoral fellow Dr Meredith Jones, previously of the University of Exeter but now in the Department of Zoology, with Dr David Bass (Zoology) have uncovered a 'missing link' in the fungal tree of life after analysing samples taken from the university's pond. Their study, published in Nature, explains the discovery of a hitherto unknown type of fungi which has fundamentally expanded the scientific understanding of this group of organisms.

"This study has been very surprising -- not least because the original sample came from the nearby pond. Fungi have been well studied for 150 years and it was thought we had a good understanding of the major evolutionary groups, but these findings have changed that radically. Current understanding of fungal diversity turns out to be only half the story -- we've discovered this diverse and deep evolutionary branch in fungi that has remained hidden all this time."

The researchers have temporarily named the new group cryptomycota -- which is Greek for 'hidden fungi'. Cryptomycota change the understanding of the whole fungi group because they lack something which was previously considered essential for the classification - a tough cell wall which is important for how fungi feed and grow, breaking down dead animal and plant biomass. Despite lacking the tough cell wall, they seem still to be very successful in the environment because of their extensive diversity and cosmopolitan distribution.

"While the first sample used in our investigation was taken from the university pond, Cryptomycota are present in samples taken from all over the world. The huge genetic diversity and prevalence of this group leads us to believe they probably play an important role in a range of environmental processes. It is possible there are many different forms of this organism with a range of characteristics we don't even know about yet. There is a lot more research to be done to find establish how they feed, reproduce, grow, and their importance in natural ecosystems."

This study is the result of new efforts to try to understand the diversity of life on Earth by taking DNA sampling out into the field. Until recent years, researchers investigating microbial diversity have sampled by growing microbes in lab cultures, but now it seems that the vast majority of life forms are never captured using these methods -- meaning most of the evolutionary complexity of life remains unsampled. This work was primarily supported by an NERC grant to Tom Richards and is a result of an international collaboration between his group and Dr Ramon Massana's group at the Institut de Ciències del Mar, Barcelona.

MDM Jones, I Forn, C Gadelha, MJ Egan, D Bass, R Massana, TM Richards (2011). Discovery of novel intermediate forms redefines the fungal tree of life. Nature doi:10.1038/nature09984

Scientists working on the diversity of life are familiar with new estimates of the number of species – we believe that there are around 1.7 million species that have been described over the past three centuries, the vast majority represented in collections such as that of the NHM.  Estimates of the total number of species that actually exist vary hugely, ranging from 10 million to up to 100 million - but the majority certainly seem to be unknown and undescribed. Contrast this with the view in the mid-Eighteenth Century, when Linnaeus thought in terms of the thousands of species that might exist, and was able to describe what he thought was a substantial proportion of life on Earth.

We know some groups reasonably well: for example the discovery of new bird species is at a low frequency and mammals similarly so, despite there being a large number of scientists who specialise in these groups.  The situation with invertebrates is rather different – we think that there are millions of undescribed species and the limiting factor is the number of scientists available to find and describe them.

But this traditional model is based on knowing that a group exists and (more or less) what a species is in that group– such as beetles, or flowering plants, or nematodes.  When it comes to very small organisms – whether bacteria or other groups, we are much less certain of the overall extent and groupings of natural diversity.

Our view has been limited in the past by the need to see the organism or to be able to culture it in a laboratory..  Our understanding now can change rapidly as a result in advances in the use of molecular biological techniques that enable us to look for distinctive DNA or RNA in the environment and compare this with what is already known.

A new discovery, led by NHM scientist Tom Richards with David Bass (both in Zoology), and collaborators from Exeter, Cambridge, Barcelona and Harvard, has opened up a new horizon in how we think about fungal diversity (Jones et al., 2011). It could represent the discovery of a new fungal phylum - a major group in taxonomic terms.

Fungi are extremely diverse – with traditional estimates of 1.5 million species.  They are more closely related - as a sister group - to animals than to plants and have traditionally been thought to have characteristic cell walls made of chitin or cellulose.  It is thought that plants, animals and fungi all originated from single-celled organisms that used flagellae to propel themselves through water (James et al., 2006).

Tom, David and their colleagues took information on known RNA diversity in fungi and compared this with new material from sea and freshwater samples from Devon in the UK.  They found a wide diversity of new RNA profiles for previously unknown organisms that were clearly within the fungi but which were distinctly different from what was already known: the new profles were most similar to a couple of unusual species in the genus Rozella.  Rozella is considered a primitive fungus because it lacks the normally characteristic cell wall (as do the newly discovered fungi) and has represented a tiny and uncharacteristic group in past understanding of fungal diversity.  The lack of a cell wall seems to make these fungi difficult to culture in the laboratory - and so difficult to find.

They also found evidence that these new and hidden fungi – which they called Cryptomycota – have three life cycle stages: one a resistant dormant cyst; a second mobile zoospores with flagellae; and a third attached to the cell of another organism (such as diatoms, which are single-celled plants).

What does this mean?  These fungi could play a significant part in ecosystems, interacting with other organisms and influencing how those ecosystems work and how other organisms live.  We don’t at this stage know how widespread they are, how diverse they are, or their ecology, but given their diversity it seems possible that they are widespread and their ecology diverse.

It also shows that our traditional methods of exploring diversity can miss major groups – if we have not been able to see organisms easily, and they cannot be cultured in the lab, we do not know that they exist, so our estimates of possible diversity could be significantly in error. What else is there to be found?

James, T. et al. (2006) Reconstructing the early evolution of Fungi using a six-gene phylogeny. Nature 443, 818-822 (19 October 2006) doi:10.1038/nature05110

Jones, D.M. et al. (2011) Discovery of novel intermediate forms redefines the fungal tree of life. Nature, Published online 11 May 2011 doi:10.1038/nature09984

http://www.nature.com/news/2011/110511/full/news.2011.285.html

The Museum's collections have a core purpose of reflecting the diversity of the natural world - animals, plants, fossils, minerals and other materials.  The collection is structured and used in the main to reflect this goal, so insects will be grouped in terms of beetles, flies, moths, bugs and others, for example.

The collection is continually reorganised and developed as understanding of natural diversity changes - so the evolutionary relationships of groups will be changed, for example, when new DNA data are gathered.  This results in additions to collections, databases and specimens and a reorganisation of knowledget that goes with the collection.

However, the collection also reflects the historical development of human ideas - understanding of evolution, geographical understanding of distribution, histories of exploration and contact between societies, developments in how collections are assembled, collaboration between scientists.  As such the Museum holds specimens and documents from major initiatives in exploration and scientific enterprise from the past 300 or so years and is of great interest beyond the core of natural scientists in biology and earth sciences.

In addition to the formal knowledge recorded with the collection, institutions such as the Museum have huge informal resources of knowledge and experience that are held by staff and developed throught their careers.  It's not often apparent to the scientists themselves what will be of interest to the world at large, but this value is being increasingly recognised.

The Museum has set up a new Centre for Arts and Humanities Research (CAHR) to foster the use of our collections (books, manuscripts, field notebooks, maps, specimen data labels, etc) by academic researchers in the humanities and arts. Its development has been based on an AHRC ( the UK Arts and Humanities Research Council) funded research project to Kingston University/NHM called ‘New Perspectives’ which revealed the rich resource of humanities research material in our collections.

The centre has raised new external funds for collaborative research with UK and foreign universities, including some staffing costs from Kingston University. An advisory board of external and internal experts have had their first formal meeting and the Centre will be formally launched on 11 July 2011.  The Centre manager is Mrs Julie Harvey (Library and Information Systems) j.harvey@nhm.ac.uk.

One of the first major meetings fostered by the CAHR is Science Voices being held at the Royal Society 12-13 May 2011. This meeting will include a keynote address on an AHRC-funded project to record the oral history of the NHM by Prof Brian Cathcart (Kingston University).  The project, Museum Lives, has involved interviewing and recording the experience and insight of scientists and will provide a resource for research by oral historians in the future.

Just a quick link through to a NERC blog on the use of Araucaria trees in investigating plant responses to higher carbon dioxide levels. The visiting researchers used NHM botany collections and those of a number of other institutions, in addition to growing and experimenting on living plants.

Araucaria includes the familar garden Monkey Puzzle tree and are part of a group of plants that reached its maximum diversity during the Jurassic and Cretaceous periods between 200 and 65 million years ago.  It is known that in conditions of higher or lower carbon dioxide, plants will have different numbers of gas-exchange pores (stomata) on their leaves.  The interest of Araucaria lies in whether the number of stomata in fossils can be used to understand more about past patterns of carbon dioxide variation and hence climate change linked to atmospheric changes.

Fossil Araucaria cones from the Jurassic