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Predicting how species and ecosystems will respond to newenvironments is an important task for biology. However, moststudies of evolutionary adaptation have considered single speciesin isolation, despite the fact that all species live in diversecommunities alongside many other species. Recent theories havesuggested that interactions between species might have a profoundeffect on how each species evolves, but there has been littleexperimental support for these ideas. The research, published May 15 in the online, open-access journal PLoS Biology , involved culturing five bacterial species in the laboratory,studying them both in isolation and mixed together in a communityof all five species. Cultures were allowed to adapt to newconditions over seventy bacterial generations. The feeding habitsof each species were then measured using chemical analyses; bycomparing chemical resource use at the start and end of theexperiment, it was possible to show how the resource use and wasteproduction of each species had evolved. The research team, from Imperial College London, found thatbacteria that evolved in a mixed community with other speciesaltered their feeding habits to share resources more effectivelyamongst themselves and to make use of each other's waste productsin a cooperative manner. In contrast, when grown alone, the samespecies evolved to use the same resources as each other, therebycompeting and impairing each other's growth. The changes in feeding habits led to a greatly improved functioningof the community of species as a whole. Communities that werereassembled with bacteria that previously evolved together werebetter, collectively, at breaking down resources than thosereassembled with bacteria that had previously evolved in isolation.Together, the results show that the way in which species adapt isgreatly altered by the presence of other species, and thatco-evolution enhances the ecological functioning of groups ofspecies. "Our findings have wide implications for understanding howspecies respond to changing conditions," says Diane Lawrence,a PhD student in the Department of Life Sciences and GranthamInstitute for Climate Change, and lead author of the study."Because all species live together with many hundred otherspecies present, the kind of phenomena observed here are likely toapply widely." For example, predicting how insects and plantswill respond to climate change over the next hundred years -- atimescale in generations similar to the one studied here forbacteria -- will need interactions with other species to bemeasured and taken into account. Similarly, the way in which the bacteria living in the human gutadapt to changes such as antibiotic treatments or a shift to ahigh-fibre diet is likely to depend on interactions among species.Tim Barraclough, who initiated the study, explains:"Engineering bacterial communities to improve human healthrequires greater understanding of the interactions among componentspecies than we currently have. Our results provide a step in theright direction to developing that understanding." The challenge now is to test whether species interactions are asimportant in shaping evolution in nature as they have been shown tobe in the laboratory. This will require scaling up theseexperiments to include the hundreds or thousands of species foundin real ecosystems. We are high quality suppliers, our products such as HTC Protective Case Manufacturer , China iPhone 4 Protective Cases for oversee buyer. To know more, please visits iPhone 4 Silicone Cases.
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