Loch fossils show life harnessed sun and sex early on

Remote lochs along the west coast of Scotland are turning up new evidence about the origins of life on land. A team of scientists exploring rocks around Loch Torridon have discovered the remarkably preserved remains of organisms that once lived on the bottom of ancient lake beds as long as a billion (1000 million) years ago. These fossils illuminate a key moment in the history of evolution when life made the leap from tiny, simple bacterial (prokaryote) cells towards larger, more complex (eukaryotic) cells which would make photosynthesis and sexual reproduction possible.The team, from Oxford University, Sheffield University and Boston College, report their findings in this week's Nature . 'These new fossils show that the move toward complex algal cells living in lakes on land had started over a billion years ago, much earlier than had been thought,' said Professor Martin Brasier of Oxford University's Department of Earth Sciences, an author of the paper. 'These new cells differ from their bacterial ancestors in that they have specialised structures including a nucleus, as well as mitochondria and chloroplasts - which are vital for photosynthesis. They also undergo sexual reproduction, leading to much more rapid rates of evolutionary turnover.' Some of these ancient fossils are so finely ornamented, and so large and complex, that they are evidence for a surprisingly early start for the emergence of complex eukaryote cells on land. Co-author Leila Battison of Oxford University said: 'What is exciting about these fossils is that they record the appearance of non-marine eukaryotic cells.