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32 Posts tagged with the zoology tag
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An interdisciplinary team of Museum mineralogists and zoologists,  with external collaborators, have been looking at the impacts of nano  particles on the environment for some years.  Silver nanoparticles  (AgNPs) are widely used in industry for manufactured goods and this may result in environmental impacts, notably within aquatic ecosystems. Silver can be toxic to living organisms when they are exposed to it by selected routes and in particular forms.  It's important that in pursuing the positive benefits of NPs, we are able to understand and avoid the negative impacts.

 

Scientists have over many years developed understanding of which substances are toxic, and why.  Sometimes this knowledge will have come about as a result of seeing the effects of unintended exposure to humans in factories or accidentally contaminated food. Exposure to toxic substances can result in death or very serious health effects to humans or other organisms.  However, we have a lot to learn - much of our understanding has arisen from particular cases or studies and one area of particular complexity is exposure through the environment.

 

We are exposed to a whole range of chemical substances in our environment, often at very low levels of concentration and sometimes over many years.  The same is true of other organisms - although the effects of particular substances will be different for different species, as a result of their different genetic makeup, diet, habitat and other factors.  Further, exposure to different combinations of chemical substances can lead to the toxic effect of a particular substance being decreased or increased in a particular and often unexpected way.

 

The use of nanoparticles has increased tremendously in recent years in industry.  Nanoparticles are very tiny particles of a substance - less than 100 nanometres in all three dimensions (one nanometre is one billionth of a metre).  This size means that they can have different chemical, physical and biological properties from larger particles, and this includes their toxic effects.

 

The study looked at estuaries, which are complex environments and often the site of human industrial developments.  Sediments in estuaries are sinks for numerous pollutants, but also habitat and food for deposit feeders (eating the sediments) such as the polychaete worm Nereis diversicolor.

 

Ingested sediments were investigated as an important route of uptake for NPs. The Museum scientists looked at N. diversicolor that had eaten sediment contaminated with either citrate-capped AgNPs (30 +/- 5 nm) or aqueous silver for 10 days. The experimental results indicate separate routes for silver to enter the cells of the worms and differing final locations of Ag delivered in dissolved and NP form.

 

N div1.jpg

 

For AgNPs an endocytotic pathway appears to be a key route of cellular uptake - endocytosis means that the NPs are ingested by the cells of the organism, engulfing the NPs into a vacuole within the cell, in contrast to the usual cross-membrane transport of dissolved substances.

 

All these findings lead to a better understanding of how organisms respond, interact and deal with NPs - this is complex and will have a substantial influence on toxic effects and environmental impact.


GARCIA-ALONSO J, KHAN F R, MISRA S K, Turmaine M, SMITH B D, RAINBOW P S, LUOMA S N, VALSAMI-JONES E 2011. Cellular internalization of silver nanoparticles in gut epithelia of the Estuarine Polychaete Nereis diversicolor. Environmental Science and Technology 45: 4630-4636.

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There is considerable international interest in the impacts of invasive species on biodiversity.  Species are described as being invasive when they cause impacts on biodiversity outside their normal range as a result of introduction or spread as a consequence of human activity.  This impact can lead to loss of native species, spread of disease, impacts on native habitats or other effects.  They are often described as invasive alien species. In the marine environment this can happen as a result of transport by ships in ballast water, or migration through new sea routes such as the Suez Canal.


Recent work from the Museum provides more evidence that the flood of invasive Red Sea species entering the Mediterranean via the Suez Canal includes fish parasites.  Dr Hoda El-Rashidy (who obtained her PhD while researching in the Zoology Department at the NHM) and Prof Geoff Boxshall (Zoology) have described two more new species of parasitic copepods from Egyptian Mediterranean waters off the coast of Alexandria.

 

Their hosts, two species of Red Sea rabbitfish (Siganus luridus and S. rivulatus) have established populations in the Mediterranean. Invasive species often leave their parasites behind, due to the sampling effect of passing through a small founder population, but the continuing discovery of invasive parasitic copepods combined with the absence of any genetic evidence of a bottleneck in their host populations, highlights the remarkable scale of the faunal invasion of the eastern Mediterranean.

 

International concern and efforts to monitor and control impacts of invasive species are significant, with an EU Strategy,  a major focus from the Convention on Biological Diversity, and a UK Non-Native Species Secretariat.  Even on a city level here in London there is coordination on selected species such as Japanese knotweed and various invasive crayfish.


El-Rashidy, H.H. & Boxshall, G.A.  2011. Two new species of Parasitic Copepods (Crustacea) on two immigrant fishes from the Red Sea of Family Siganidae. Systematic Parasitology 19: 175-193. DOI 10.1007/s11230-011-9298-7


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Fin loss in a spiny eel

Posted by John Jackson Jul 19, 2011

Vertebrates - mammals, birds, fish and amphibians - have broadly the same body plan with two pairs of limbs.  However, over time, some species and groups have lost one or both pairs of limbs.  Many others have reduced limbs.  Whales, snakes, caeclian amphibians and a range of fish are some of the examples.

 

Modern scientific research has a strong interest both in the patterns of development and in how and why these change as a result of genetic evolution - it does appear that different genes can be involved in limb reduction and loss in different groups. 

 

Drs Ralf Britz and Lukas Rüber (NHM Zoology) and colleagues from University College London and the South African Institute for Aquatic Biodiversity, Grahamstown reported the first case of pectoral fin loss in the Mastacembelidae (Teleostei: Synbranchiformes) with the discovery of a new species of spiny eel from Lake Tanganyika in the Journal of Zoology.

 

A previous evolutionary phylogeny of mastacembelids using comparisons of genetic differences between different species,  coauthored by Dr Rüber , had placed the new species Mastacembelus apectoralis sp. nov. within the Lake Tanganyikan species flock, having diverged from its sister species M. micropectus around 4.5 million years ago. M. micropectus also shows a reduction in the size of its pectoral fin and endoskeletal girdle, and has largely cartilaginous pectoral radials and a reduced number of pectoral-fin rays. This is in contrast to the bony skeletons of most fish species in this group

 

The loss of pectoral fins and reduction of associated girdle elements in M. apectoralis represent another independent occurrence of this evolutionary phenomenon within teleosts. The discovery of this species highlights the exceptional diversity of the biodiversity hotspot, Lake Tanganyika, the understanding of which is of critical importance with the pressures of pollution, overfishing and climate change threatening the speciose and evolutionarily significant diversity of this ancient lake.


Brown, K. J., Britz, R., Bills R., Rüber, L. & Day J. J. (2011). Pectoral fin loss in the Mastacembelidae: a new species from Lake Tanganyika. Journal of Zoology April 2011 doi:10.1111/j.1469-7998.2011.00804.x

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David Gower and Mark Wilkinson, NHM Zoology


It is well known that global diversity is generally under threat from factors such as habitat destruction, pollution, climate change, hunting, invasive species and disease. It takes very large collaborative efforts in order to be able to quantify an accurate overview of the latest situation, but this is needed because donors, policy makers and managers want to know to what extent conservation efforts can make a positive impact.


As part of just such an effort we contributed to an article published in the journal Science (Hoffman, M. et al. (2010) Science 330: 1503-1509).The article reported that although an increasing number of the World’s vertebrate species are threatened by extinction, the deterioration would have been at least one-fifth again as much in the absence of conservation efforts.


The Science study analysed up-to-date conservation assessments for nearly 26,000 of the World’s approximately 63,000 named species of vertebrates (fishes, amphibians, reptiles, birds, and mammals). The assessments are in the form of formal categorizations on the International Union for Conservation of Nature’s (IUCN) “Red List” (www.iucnredlist.org) - the widely accepted 'standard’ for determining species’ risk of extinction.


zoology Annual report 2010-2011 final.jpg


Balebreviceps hillmani, a threatened amphibian from the Bale Mountains, Ethiopia. [photo by DJ Gower]


Analyses of the Red List data revealed that 20% of vertebrates are classified as Threatened, with this percentage increasing. On average, 52 species of mammals, birds, and amphibians move one category closer to extinction every year (there are eight categories in all). However, of the 1,000 or so species that had undergone a change in their categorization in recent years, about 7% underwent an improvement in status, and almost all of these are part of conservation projects. Thus, in the absence of conservation effort, many more vertebrates would have slipped closer to extinction. Most of these improving vertebrate species are birds and mammals – those groups most often targeted by conservation projects. Only four species of amphibians have improved in status, and more than 40% of this group is threatened; so much remains to be done.


Vertebrates are generally very visible, often charismatic (and vital) components of ecosystems, and they commonly comprise conservation ‘flagship’ species, frequently with high cultural value. However, vertebrates comprise only 3% or so of known organismal species. The conservation status of many non-vertebrates has yet to be determined based on Red List criteria.


The Science paper was authored by a whopping 174 scientists. Like many of these researchers, we played a primary coordinating role that facilitated completion of the dataset. In particular, we finalized Red List assessments for all species of caecilian amphibians (in a workshop held at the NHM), and for some burrowing snakes. Museum science is essential for understanding species’ conservation status because its core business is the taxonomic and ecological work that underpins all other studies of life.


The Science paper was announced in a press release to coincide with the release of the latest Red List update at the Tenth Conference of the Parties to the Convention on Biological Diversity, Nagoya, Japan, October 2010. The paper ends with the following statements: “The 2010 biodiversity target may not have been met, but conservation efforts have not been a failure. The challenge is to remedy the current shortfall in conservation action to halt the attrition of global biodiversity.”


David Gower and Mark Wilkinson are Researchers in the Herpetology Research Group, NHM Department of Zoology

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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

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The Mid-Atlantic ridge is the zone running north to south along the bed of the Atlantic Ocean where two major tectonic plates are gradually moving apart, causing volcanic and other geological activity.  As the plates separate slowly, the rock fractures and sea water becomes heated by contact with hot and molten rock below the surface.  This hot water dissolves minerals and contains highly concentrated levels of a range of chemical substances. 

In places this water is forced from hydrothermal vents on the bed of the sea, forming plumes of superheated hot water that rise into the ocean, sometimes carrying thick black particulates.  As the water cools slightly at the vent, various dissolved chemicals are deposited to make large mineral structures such as chimneys and other forms. Exploration of this environment has been increasing over the past forty years with the development of advanced equipment and remotely-operated vehicles: small submarines that carry sophisticated scientific probes and cameras.

The bottom of the ocean is not generally fertile in comparison to coastal seas, but hydrothermal vents are home to dense populations of animals, supported by bacteria that flourish in the chemical-rich waters. The high sulphur and mineral content of the water would make it toxic to most organisms, but some species have evolved to tolerate the temperature and chemical environment.  The animals either consume the bacteria (or one another) directly, or have, in the case of bivalve mussels, symbiotic bacteria in their gill tissue that enables them to use sulphur compounds to produce energy.  These environments are small islands of fertility on the ocean floor, of great evolutionary and ecological interest.

Dr Adrian Glover (Zoology) is part of a team of co-authors in an international team from Portugal, France and the UK who have recently described assemblages of animals from the 11m-high Eiffel Tower structure in the Lucky Strike hydrothermal vent field 1700 metres deep on the Mid-Atlantic Ridge, just to the south of the Azores. Pictures of the Eiffel Tower can be seen on the IFREMER site.

They sampled temperature and sulphide were measured in the water at two different assemblages: one dominated by shrimps and the other by mussels. Temperature, rather than sulphide concentration, appeared to be the major environmental factor affecting the distributions of the resident hydrothermal vent species. The highest temperature variability and the highest maximum recorded temperatures were found in the assemblages visibly inhabited by alvinocaridid shrimp and dense mussel beds of large Bathymodiolus azoricus, whereas the less variable and more stable habitats were inhabited by smaller-sized mussels with increasing bare surface in between.

 

D Cuvelier et al. (2011) Hydrothermal faunal assemblages and habitat characterisation at the Eiffel Tower edifice (Lucky Strike, Mid-Atlantic Ridge). Marine Ecology (2011) doi:10.1111/j.1439-0485.2010.00431.x.

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We know that animals come in a whole range of different shapes and sizes – there is an immense variety in form, ranging from the smallest of flatworms to the blue whale.  One area of real interest to scientists is understanding how form changes with size and why.  Are there limits to size that are imposed by the basic materials that make up an animal’s body, or the arrangement of body parts that have been inherited?

 

Take modern mammals, for example: the Blue Whale at 180 tonnes shows that mammals can grow to a very large size in a marine environment with modifications to the basic mammalian body plan.  But on land, elephants are the largest living mammals with a maximum mass of over 10 tonnes – around half the probable mass of Paraceratherium which lived approximately 20-40 million years ago.  The largest land animal is likely to have been the dinoasaur Argentinosaurus with a mass of up to 60 tonnes, living 95 million years ago.
 
Some body parts can be in the same proportion in small and large animals (isometric), but other characteristics will be in different proportion in large and small animals (allometric) – so the diameter of leg bones is thicker in proportion to body size in larger animals than in smaller animals.

 

A Museum collection provides an ideal resource to compare different body structures and biomechanics, and to try to explain how and why body plans change with size and environment: tens of thousands of individual organisms are available for study, with expert support from curators.

 

How does internal bone structure change with size?  Dr Sandra Shefelbine of Imperial College London with colleagues from IC and the Royal Veterinary College studied bones from ninety species of mammal and bird ranging in size from shrews to elephants, using the Natural History Museum’s collections with other material from the University of Cambridge and the Zoological Society of London.
 
Their study, funded by the UK Biotechnology and Biological Sciences Research Council (BBSRC) and published in the Proceedings of the Royal Society B, looked at the structure of the spongy bone near joints that helps sustain impact and weight when the animal jumps or walks. They showed that the density of spongy bone near joints was very uniform between species but that the internal struts (trabeculae) that give the bone its spongy appearance got thicker and further apart as species got larger.

IMG_2202.jpg

 

What this work helps to demonstrate is that some shared characteristics of different organisms can change more than others as body sizes increase.  So the larger animals have larger bones in absolute terms, but the bone does not get more dense to cope with higher body mass – the relative thickness of the trabeculae increases instead. So rather than having denser bone (which would require more resource to grow and require relatively more energy to move) to sustain greater weight, the structure of bone changes allometrically in larger species.

 

BBSRC have supported this work because of the fundamental interest of the science but also because understanding of the mechanics of bone structures can support other work to combat fractures and osteoporosis.  Professor Douglas Kell, BBSRC Chief Executive said: "Bones are remarkably versatile structures able to produce intricate mechanisms in the ear and to support the weight of an elephant. However, in elderly people bones can become fragile and prone to breakages which can lead to serious health problems and drastically reduce quality of life. This research has increased our understanding of how bones have evolved across the animal kingdom and may lead to new insights about how to keep them strong and healthy."

 

The NHM curators who helped the researchers access collections material were Louise Tomsett and Roberto Portela-Miguez

 

Michael Doube, Michal‚ M. Klosowski, Alexis M. Wiktorowicz-Conroy, John R. Hutchinson, and Sandra J. Shefelbine (2011) Trabecular bone scales allometrically in mammals and birds Proc. R. Soc. B  published online before print March 9, 2011, doi:10.1098/rspb.2011.0069

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The discovery of hydrothermal vents in the late 1970s triggered an  enormous biological interest in chemoautotrophic organisms dependant on  previously unknown symbioses with sulphide and methane oxidising  bacteria. Molluscs, particularly bivalves, are the most diverse and  widespread group of chemosymbiotic animals ranging from the intertidal  to hadal depths. Thirteen international speakers will review the  biology, diversity, evolution,host-symbiont interactions and habitats of  these molluscs.

 

The Malacological Society of London and Department of Zoology, The Natural History Museum, are organising a meeting 7 - 8 April 2011 Chemosymbiotic molluscs and their environments: from intertidal to hydrothermal vents at The Natural History Museum, Cromwell Road, London SW7 5BD

 

1000-1800h, 7 April 2011, Flett Theatre
1000-1300h, 8 April 2011, Sir Neil Chalmers Seminar Room

 

No registration fee but for catering purposes PLEASE LET US KNOW IN ADVANCE if you will be attending.

 

Organisers and contact: John Taylor and Emily Glover  j.taylor@nhm.ac.uk

 

 

Speakers and titles

 

  • Sarah Samadi (Systématique, Adaptation et Evolution, Université Pierre et Marie Curie, Paris) ‘Mytilids associated with sunken wood shed new light on the evolution of Bathymodiolinae’
  • Sebastien Duperron (Systématique, Adaptation et Evolution, Université Pierre & Marie Curie, Paris) ‘Connectivity and flexibility of mussel symbioses: how to cope with fragmented and variable habitats?’
  • Nicole Dubilier (Max Planck Institute of Marine Microbiology, Bremen) ‘The unrecognized diversity of bacterial symbionts in chemosymbiotic molluscs’
  • Clara Rodrigues (Universidade de Aveiro, Portugal) ‘Chemosymbiotic bivalves from mud volcanoes in the Gulf of Cadiz: an overview’
  • Graham Oliver (National Museum of Wales, Cardiff) ‘Thyasiridae: the known and the unknown: setting priorities for future research’
  • Heiko Sahling (Geosciences, University of Bremen) ‘The geological and geochemical environment of vesicomyid clams’
  • Elena Krylova (Institute of Oceanology, Moscow) ‘Vesicomyidae (Bivalvia): current systematics and distribution’
  • Steffen Kiel (Geobiology, University of Göttingen) ‘The fossil history of chemosymbiotic bivalves’
  • John Taylor and Emily Glover (Zoology, NHM London) ‘Ancient chemosymbioses – contrasting diversification histories of Lucinidae and Solemyidae’
  • Olivier Gros (Université des Antilles et de la Guyane, Guadeloupe) ‘Codakia orbicularis gill-endosymbiont produces quorum-sensing signals of the AHLclass: putative impact on the bacterial population control in lucinids’
  • Caroline Verna (Max Planck Institute of Marine Microbiology, Bremen) ‘Lucinid symbiont diversity: influence of host selection, geography, habitat and depth’
  • Jenna Judge (Integrative Biology, University of California Berkeley) ‘Testing diversification processes in chemosymbiotic gastropods: a phylogenetic approach’
  • Adrian Glover (Zoology, NHM London) 'Chemosynthetic ecosystems of the Antarctic: a test of dispersal'
  • Paul Dando Marine Biological Association, Plymouth "Fjord thyasirid populations and sediment geochemistry"
  • Matthijs van der Geest (Royal Netherlands Institute for Sea Research) "Ecological importance of chemoautotrophic lucinid bivalves in the Banc d'Arguin (Mauritania) intertidal ecosystem"
  • Karina van der Heijden (Max Planck Institute of Marine Microbiology, Bremen) ‘Biogeography of Mid-Atlantic Ridge hydrothermal vent mussels and associated bacterial symbionts’
  • Graham Oliver & John Taylor 'First confirmation of bacterial symbiosis in Nucinellidae'
  • John Hartley (Hartley Anderson Ltd, Aberdeen) ’Chemosynthetic bivalve responses to oil contamination around North Sea wells and platforms’
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Charles Darwin spent much of his later life at Downe in Kent: thinking, writing and experimenting in an emphatically rural landscape.  But he retained an interest in marine animals, a fascination that developed in his early years at university and during his extended voyage around the world on HMS Beagle.


Professor Phil Rainbow (Keeper of Zoology) has published a keynote presentation in the journal Marine Ecology on the influence of marine biology on Charles Darwin - and the influence of Darwin on marine biology.

 

Darwin made his first forays into the world of marine biology as a medical student in Edinburgh from 1825 to 1827. He came under the influence there of the Lamarckian Robert Grant, and developed an understanding of the simple organisation of the early developmental stages of marine invertebrates. Yet Darwin could not accept Lamarckian transmutation - a complex set of ideas on evolution that preceded the idea of natural selection.  (Lamarck was a French scientist who, among other ideas, argued that a characteristic [such as larger muscles as a result of frequent exercise] acquired during an organism's life would be passed on to descendants and resulted in evolutionary change: Darwin's later development of natural selection as an explanation for evolution discredited Lamarck's ideas.)

 

The voyage of the Beagle gave him intense exposure to a wide range of marine environments around the world and led to Darwin's perceptive theory on the origin of coral reefs, an origin still mainly accepted today. This theory was linked closely to the uniformitarianism (gradual geological change over millions of years) of the geologist Charles Lyell, depending on the slow, gradual growth of billions of coral polyps keeping pace at sea level with slow sinking of land to produce an atoll.

 

Darwin's interest in variation in animals and plants led him to examine many different organisms, both wild and domestic. However, he was aware that his unusual scientific background meant that he had not developed a his reputation on the basis of detailed scientific study in a particular area.  Therefore, from 1846 to 1854 Darwin focused on barnacle diversity and revolutionised understanding of barnacles, producing the monographs Living Cirripedia that are still relevant today.

 

capitulum-mitella4_57395_1.jpg

Capitulum mitella

 

Darwin's barnacle studies gave him the credibility to pronounce on the origin of species; he found great variation in morphology, and a series of related species with remarkable reproductive adaptation, culminating in the presence of dwarf males. Barnacles laid out an evolutionary narrative before him, and contributed greatly to his qualification and confidence to write with authority on the origin of species by 1859.


PS Rainbow (2011) Charles Darwin and marine biology. Marine Ecology. doi:10.1111/j.1439-0485.2010.00421.x

 

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Worm Sperm and Evolution

Posted by John Jackson Mar 4, 2011

Drs Tim Littlewood and Andrea Waeschenbach (Zoology) have collaborated with colleagues from Switzerland and Japan on a paper, recently published in the Proceedings of the National Academy of Sciences, that attracted widespread media attention from the science and popular press. Headlines such as “‘Worm porn’ sheds light on evolution of sperm” (MSN Science) and “X-rated worm movies reveal sex secrets” (Nature News) reflect the more restrained coverage.

 

It is a continuing challenge in science to explain why sex evolved in different species in such a variety of forms - internal or external fertilisation; separate sexes or hermaphrodites; mate selection; number of offspring; number of mates; timing of reproduction; and many other questions.  Sperm in particular are intriguing - these are highly specialised cells with the function of exchanging genetic material, evolved to survive and function in quite different situations in different species.  The huge variety of different sorts of sperm cells reflects the variety of different reproductive strategies in various groups of organism.

 

This study looked at a number of related species of a small transparent flatworm - Macrostomum. The team used a robust molecular phylogeny (developed by TL and AW) using DNA to define evolutionary history of the worms.  They then looked at mating strategies, the morphology of the bodies and the types of sperm in different species.

 

They found that one group of worms had very complex sperm with spines and a pattern of hermaphrodite exchange of sperm cells.  However, a different strategy had evolved in one member of this group and in four worms in another group in which the sperm is injected by one worm into the body of another. In these injecting species, the form of the sperm has evolved to become simpler, losing certain characteristics such as spines: the form of sperm seems to be related to mating techniques. It seems possible that the hypodermic injection gives certain advantages in some species - this might be to avoid competition from the sperm of rivals, or to avoid female rejection of sperm, but more work will be needed to answer this question.

 

The team was led by Dr Lukas Scharer (University  of Basel, Switzerland) and included Dr Dita Vizoso (Basel) and Dr Wataru Yoshida (Hirosaki University,  Japan).

 

Schärer, L., Littlewood, D.T.J., Waeschenbach, A., Yoshida, W. & Vizoso, D.B. (2011). Mating behaviour and the evolution of sperm design. Proceedings of the National Academy of Sciences USA 108:1490-1495.


 

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Just over one hundred years ago in Feburary 1911, Captain R.F. Scott RN received news from Roald Amundsen that he was intending to make a bid for the South Pole in competition with Scott’s. Scott’s expedition had a range of important scientific goals: the race for the Pole for which he is best known was only one of the objectives. The science involved resulted in a number of Antarctic collections, some of which are in the Museum today.

 

These collections have been used to show a dramatic doubling in the growth of bryozoans in Antarctic seas in the last twenty years. Bryozoans are tiny colonial animals that encrust rocks, algae and other objects beneath the sea, filtering food from the water.  It is another use of older collections that could never have been anticipated at the time of collection, but shows the value and importance of these collections to modern science and current concerns.

 

Dr Piotr Kuklinski, a Scientific Associate of the Museum who works for the Polish  Academy of Sciences Institute of Oceanography, has collaborated with other scientists from the British Antarctic Survey and US institutions to examine collections to tell how growth has changed over time and to suggest reasons why this might be happening.

 

They looked at a whole series of Antarctic collections in the Museum from 1909 to the 1930s, and other collections in the US and New Zealand up to the present day.  The species Cellarinella nutti from the Ross Sea was used – it shows annual growth lines as the colony expands and so yearly growth can be measured. The growth measurements showed no particular change in rates of growth from 1890 to 1970, but there was a rapid increase in growth from the 1990s to the present day.

 

Why is this happening?  Growth seems to be increasing because of increased availability of food – tiny single-celled plants known as phytoplankton. This increase would result from higher concentrations of phytoplankton or a longer growing season. Climate change?  Probably not - the scientists point out that there is little evidence of changes to sea ice or water temperatures in the Ross Sea.

 

However, they do suggest that this may be linked to depletion of stratospheric ozone – the ozone holes that occur in the Antarctic summer.  This could be causing stronger west winds that result in currents bringing in more nutrients to the area, in turn resulting in higher growth of plankton and higher growth of bryozoans.  Our understanding of the detail of these questions helps refine our understanding of the Earth’s carbon cycle, which is closely linked to our climate system.

 

The authors conclude ‘Amundsen claimed that Scott's “..British expedition was designed entirely for scientific research. The Pole was only a side-issue…”. Being first to reach the pole was foremost in fundraising and probably in Scott's thinking but coming second in the ensuing ‘race’ and dying there completely overshadowed the many scientific achievements of the expedition. However, the baselines that they established and crucial subsequent curation may prove key to interpretation of trends with significance way beyond the polar regions.’

 

David K.A. Barnes, Piotr Kuklinski, Jennifer A. Jackson, Geoff W. Keel, Simon A. Morley, Judith E. Winston (2011) Scott's collections help reveal accelerating marine life growth in Antarctica.  Current Biology - 22 February 2011 (Vol. 21, Issue 4, pp. R147-R148) doi:10.1016/j.cub.2011.01.033

 

 

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St Valentine's day is better known for sentiment, but in addition to the death of the eponymous saint, Captain James Cook died in Hawai'i in on the morning of 14 January 1779 during the voyage of the Resolution.  The Museum has strong connections with Cook and his collaborators, with a tremendous legacy of collections, drawings, art and other records.

 

In particular, Sir Joseph Banks, Daniel Solander and Sidney Parkinson all travelled with Cook on his earlier voyage on the EndeavourPlant collections from this voyage and others originating from Banks are held in the Museum's Botany department collections. Illustrations from the Library are described on the Endeavour botanical illustrations pages.  More of the Museum's resources are available on ArtStor, but this is currently only available via some academic institutions. Further images can be found on the NHM picture library by searching for "Endeavour" or "Resolution".

 

B000973X.jpg

Barringtonia calyptrata

 

Cook is particularly well known for his supreme skill in navigation and naval mapping. In the words of the Oxford Dictionary of National Biography "In his three voyages to the Pacific, Cook disproved the existence of a  great southern continent, completed the outlines of Australia and New  Zealand, charted the Society Islands, the New Hebrides, New Caledonia,  and the Hawaiian Islands, and depicted accurately for the first time the  north-west coast of America, leaving no major discoveries for his  successors. In addition the scientific discoveries in the fields of  natural history and ethnology were considerable and the drawings made by  the artists were of great significance."

 

In other words, he transformed the 18th Century European view of the Pacific.  He was also recognised for his acheivements in practical health care, developing new ways of preventing the disease scurvy, caused by a deficiency of vitamin C.


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Adrian Glover (Zoology) and Helena Wiklund have also been awarded a Marie Curie Intra-European Fellowship for Helena to work on deep sea biology.  This Marie Curie scheme, funded by the European Union, allows experienced EU researchers to work in other EU countries to develop skills and collaboration, producing high-quality science.  The NHM bids successfully for funds to a wide range of research funding agencies each year in the UK and elsewhere.

 

They will be working on worms in the deep sea: the last unexplored frontier on Earth, where in recent years many hundreds of new species have been discovered. We are familar with shallow coastal seas affected by tidal currents, richly productive and fertile.  In contrast, the deep sea has many areas where nutrients are scarce, cold and subject to high pressure, deep ocean basins over 4 kilometres below the surface.  The lives of organisms in the deep sea are often very different from those of related species near the surface.

 

A key question in deep-sea biology is that of whether and how deep-sea animals are able to disperse. Many organisms, such as worms, have limited abilty to move over any distance as adults: some have planktonic young that can be carried over distance by currents.

 

The dominant idea for the deep sea has been one of cosmopolitanism: that animals are relatively mobile at certain stages of their lfe cycle and have easy access to all ocean basins around the world. However, this has been recently challenged and for many species there may be barriers to dispersal in the form of substrate specialisation (the requirement to live in particular types of sediment) limited mobility or particular reproductive characteristics.

 

This study will target one of the most abundant and species-rich groups, the polychaetes. To answer questions of dispersal and evolution in the deep sea Helena will study three contrasting groups of polychaetes:one group with mobile planktonic larvae; a second group with direct-developing larvae, similar in form to the adults; and a third group, the newly discovered genus of ’bone-eating’ worms, Osedax, that are sessile (non-mobile) and exist on the most specialised of habitats – whale bones on the sea floor. (One of which, Osedax mucofloris, was a NHM species of the day in 2010)

 

osedax-sem_69101_1.jpg

Osedax mucofloris


The study will use molecular data (such as from DNA analysis) from material from several ocean basins to construct phylogenies (evolutionary trees) to evaluate the relationships within the three groups.  It will have great value in understanding species formation, population connections and the processes that drive biodiversity in the deep sea.

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Myxozoans are a diverse group of microscopic endoparasites - tiny worm-like parasites that live within other organisms, depending on their hosts for nutrition, oxygen and other needs.  Examples of myxozoans featured as NHM species of the day in 2010 were  Buddenbrockia plumatellae  and Tetracapsuloides bryosalmonae.

Scientific study of evolution and evolutionary relationships has in the past often depended on study of the physical forms of organisms (morphology) and comparing particular characteristics, such as body plan, organs, limbs or other features. Similarities and differences in these characters are used to classify the organisms.  However, with some organisms, particularly parasites, evolution can result in the loss of features with an apparently more simple body form.  This makes clarification of relationships difficult.  However, the use of DNA sequences can provide additional information that leads to understanding of evolutionary relationships and a clear evolutionary classification (phylogeny).

Myxozoans have been the focus of much controversy regarding their phylogenetic position. Two dramatically different hypotheses have been put forward for the position of the Myxozoa within Metazoa (all multicelled animals).

The first hypothesis, supported by rDNA sequence data (a specific kind of DNA from the ribosomes of the cell), suggests that Myxozoa is a sister group to Bilateria (all organisms with a single line of symmetry to their body plan, ranging from simple worms to humans, and representing most groups of animals). However, the alternative hypothesis, supported by phylogenomic data (a broader range of DNA) and morphology, suggests that Myxozoan are cnidarian. Cnidarians are an animal group containing sea anemones, coral and jellyfish that have radial symmetry and a very different body plan from the Bilateria.  These different ideas represent evolutionary events that would have occurred hundreds of millions of years ago.

Professor Beth Okamura (NHM department of Zoology) and colleagues, funded by the US National Science Foundation, investigated these conflicting hypotheses with Buddenbrockia and explored the effects of missing data, different statistical methods, and different models on evolutionary classification.  In addition, they identified subsets of the data that most influence the placement of Myxozoa and explored their effects by removing them from the datasets.

The results confirm the existence of two relatively stable placements for myxozoans and demonstrate that conflicting signal exists not only between the two types of data but also within the phylogenomic dataset. These analyses underscore the importance of careful model selection, taxon and data sampling, and in-depth data exploration, when investigating the phylogenetic placement of highly divergent taxa.

In other words, the  available information does not yet allow Myxozoans to be placed  definitely within one or other fundamental group - further development of data, and new scientific techniques will be needed to answer this question, but the work in the paper is important in defining the current limits and uncertainties of this area of science, and suggests ways forward for the future.

Evans, N.M., Holder, M.T., Barbeitos, M.S., Okamura, B. & Cartwright, P. 2010. The phylogenetic position of Myxozoa: Exploring conflicting signals in phylogenomic and ribosomal datasets. Molecular Biology and Evolution 27: 2733-2746. doi:10.1093/molbev/msq159

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Trichuriasis is a common intestinal worm infection in Africa and in other parts of the World, affecting almost 800 million people.  Trichuris is the nematode worm that causes the condition and is usually transmitted by faecal contamination of soil or food.  Heavier infestation can lead to pain and a range of health impacts that can seriously diminish quality of life and which may contribute to premature death, particularly in children. 

The World Health Organisation describes trichuriasis as one of the Neglected Tropical Diseases - diseases that thrive in conditions of poverty. Unsafe water, lack of access to health services, inadequate housing, malnutrition and poor sanitation all increase vulnerability to infection by this and other diseases such as leprosy, dengue and schistosomiasis.

It is not uncommon for people to suffer from both trichuriasis and from schistosomiasis, another condition caused by a parasite, and these may be treated by the same drugs. Research on the disease leads to better understanding and more effective treatment.

Dr Stefanie Knopp undertook her PhD research on treatment of trichuriasis at the University of Basel in collaboration with Dr David Rollinson and Dr Russell Stothard in the Museum's Department of Zoology, who are specialists in schistosomiasis.  She has recently published important research from her PhD in Clinical Infectious Diseases (a high-profile journal with an impact factor of 8.3) in a paper on on the treatment of trichuriasis in Zanzibar, Tanzania. 

Single doses of the drugs albendazole and mebendazole had in the past shown limited effectiveness in the treatment of trichuriasis. The combination of albendazole with ivermectin was known to improve treatment, but a mebendazole–ivermectin combination had not been previously investigated.

The research showed that addition of ivermectin improves the therapeutic outcomes of both albendazole and mebendazole against Trichuris trichiura, and may be considered for use in soil-transmitted helminth control programs and individual patient management.

 

Knopp S, Mohammed K A, Speich B, Hattendorf J, Khamis I S, Khamis A N, Stothard, J R, Rollinson D, Marti H and Utzinger, J  (2010) Albendazole and Mebendazole Administered Alone or in Combination with Ivermectin against Trichuris trichiura: A Randomized Controlled Trial.  Clin Infect Dis.  51 (12): 1420-1428. doi:                                                                          10.1086/657310

 

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