Rotten Fish and Fossils

Images shows progressive stages of decay of a close relative of vertebrates, the lancelet (AKA amphioxus). As they rot, specimens look more and more like fossils from the earliest parts of the vertebrate evolutionary tree. (image credit: Mark Purnell, Rob Sansom, Sarah Gabbott, University of Leicester).

Our palaeobiological research into how decay influences the preservation and interpretation of soft tissues in the fossil record has been highlighted by various agencies and media reports, and was selected for presentation at the Royal Society Summer Science Exhibition. Check out the Rotten Fossils website for details.

Drilling into the Earth’s oceans: a tale of climate change and Earth’s evolution

In 2009, six scientists, including PhD students and postdoctoral Research Associates, from the University of Leicester will spend a total of 12 months at sea through participating in 5 Integrated Ocean Drilling Program (IODP) expeditions. These expeditions are scheduled to drill in the Pacific Ocean, on the North American margin of the Atlantic Ocean, in Nankai Trough, offshore Japan and on the ancient Great Barrier Reef, NE Australia. The expeditions address a range of scientific objectives: from recovering data from the oceanic sedimentary archive to enable reconstruction of past climatic and tectonic conditions over geological (millions of years) timescales to the fundamentals of plate tectonics through investigating character of rocks and sediments material that will be transported by the plate subduction system.
The Integrated Ocean Drilling Program (IODP) is an international marine research program that explores Earth's history and structure recorded in seafloor sediments and rocks. This year's activities are part of a 10-year program (2003-2013). Through an international consortium involving the University of Leicester (lead) in partnership with Aachen and Montpellier and in association with the Lamont Doherty Earth Observatory, USA, we provide major support and expertise in the fields of wireline logging, core-log integration and petrophysics on a variety of drill platforms. We hold contracts to provide logging services and expertise worldwide to the IODP and IODP Research Associates Drs Jenny Inwood, Louise Anderson and Sally Morgan will participate as petrophysicists on mission-specific and riserless (Joides Resolution) Expeditions. In addition, we have encouraged our PhD students to apply to sail as scientists, Peter Fitch (currently at sea in the Pacific) and Joanne Tudge (Nankai Trough, offshore Japan in the Autumn 2009) successfully gained places on IODP Expeditions.
IODP builds upon earlier successes of the Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP), which revolutionized our view of Earth history and global processes through ocean basin exploration. IODP has expanded the reach of these previous programs by using multiple drilling platforms, including riser, riserless, and mission-specific, to achieve its scientific goals.

Contact: Dr Sarah Davies
Email: sjd27@le.ac.uk
Phone extension 3624

Fossils, fish and chips: a study of eating and evolution

Work by the internationally recognised palaeobiology group at the University of Leicester regularly graces the pages of the best scientific journals, and attracts media attention from around the world. Their research focuses on understanding of the processes and patterns of the evolution of life, but among many highlights, recent research on sticklebacks stands out as a worth shouting about. The following information is based on the submission to the Times Higher Awards for research Project of the Year, for which this research was shortlisted.

You are what you eat- but how do you set about proving this over a span of a few millennia?

A Leicester-led international study sought to determine the extent environmental change impacts the evolutionary process and test the hypothesis that speciation and evolutionary change were driven by shifts in feeding.

But there is a fundamental problem in the study of speciation: field and laboratory experiments take place over the limited spans of human timescales, a few decades at best, yet species originate over much longer intervals of time.

The primary objective of the study was to bridge this gap using a new technique – involving fish and chips!

By analysing the microscopic wear patterns- or tiny chips - that form on a fish’s teeth as it feeds, the scientists aimed to interpret the dietary preferences and feeding ecology of 10-million-year-old fossil fishes and examine if changes in feeding had impacted on the evolution of the fish. This kind of study, published in the journal Science, has previously not been possible.

The study is important because understanding how ecology controls the origin of new species is central to understanding evolution with significant implications for conservation biology and for evaluating how organisms respond to environmental change.

The research team, led my Dr Mark Purnell (Geology) and Prof Paul Hart (Biology) captured living stickleback, fed them different kinds of food in different conditions, and then examined their teeth using a powerful electron microscope. The team also looked at the teeth of wild stickleback, which had been feeding naturally, from Alaskan lakes. From this, they got a clear picture of tooth wear in living fish, which they could compare with the fossils.

The work, funded by the Natural Environment Research Council, revealed for the first time how changes in the way a fossil animal fed affected its evolution.

Stickleback are spiky little characters, with armour and spines on their sides and along their backs. The researchers found that evolutionary changes in these characteristics were closely linked to how stickleback fed. As feeding shifted, over thousands of years, away from the lake bottom to open water the stickleback in the fossil sequence evolved to have fewer spines.

Scientifically, this is highly significant. This is the first time that the relationship between feeding habits and evolution has been directly testable using fossils that record real directional evolutionary change over many thousands of years. Another key milestone was to demonstrate that the methods developed actually work.

Amongst other applications, the researchers are currently investigating how the method can been applied to commercially important fish species like cod, for example, to understand how overfishing and climate change have affected feeding patterns and cod numbers.

The research was selected as a top NERC achievement by the funding body. A picture produced by the research team was selected by Nature as one of its ‘images of the year’. It received widespread media coverage and included BBC television footage as well as a picture story in the Times Higher.

The prize winning image – selected as Image of the Year by Nature
 
A prey’s-eye view of a stickleback, showing the rows of small teeth lining the jaws. Each tooth is less than a millimetre long, and roughly the thickness of a human hair. The skeleton has been stained to show the bones. Picture credit: Mark Purnell, University of Leicester

Contact: Dr Mark Purnell

Email: map2@le.ac.uk
Phone extension 3645