Coevolution

This article applies the information ecology framework to explore Aula C, the headquarters of an Italian student collective that is part of the Anomalous Wave movement. It draws on a multimodal ethnography that includes participant observation and 17 semistructured interviews. Findings highlight the interrelationships among actors, practices, and technologies that constitute a system characterized by diversity, in which members of radical tech groups act as keystone species. By pointing out the coexistence and coevolution of activists and their tools, this article tries to overcome theorizations that do not consider the whole media environment with which activists interact. The newest application, it is shown, may in fact not be the most used technology for activism.

In order to cater for the predicted growth in global population and aspirations for increased living standards, the world needs to increase substantially its level of agricultural production and sustain agriculture’s increased productivity. New technologies may enable this to occur but they also bring with them increased sustainability problems. There are many complex dimensions to achieving agricultural sustainability such as deciding on what agricultural attributes are worth sustaining and considering what trade-offs in objectives are required. These issues are discussed from a conceptual point of view. It is also shown using economic theory that market-based agriculture limits the opportunity for individual farmers to adopt sustainable agricultural techniques because of competitive economic pressures. It is argued that while modern agricultural methods and increased inter-regional trade have substantially increased agricultural supplies, they have also exacerbated the problem of sustaining agricultural production and yields and have had a disequilibrating effect on rural communities. Although genetic engineering is seen by some as a way forward for increasing agricultural production, it is shown that GMOs do not ensure sustainability of agricultural production and that they can be a source of rural disharmony and can threaten the sustainability of farming communities. Extension of intellectual property rights in new genetic material in recent times, particularly the granting of patents not only on techniques for producing GMOs but on the organisms themselves, have added to sustainability problems faced by modern agriculture.

Economic, social and natural environmental systems are interdependent, and economic systems cannot be assessed in isolation from an interconnected whole.  Many parts of Asia face increasing market intrusion and forced changes in economic mechanisms and rights without concomitant social and technological co-evolution.  Consequently, serious problems for economic, social and environmental sustainability are being experienced by local communities, especially in remote regions and in peripheral areas such as Northeast India and in hilly regions of China.  Rapid Asian economic growth, extension of markets and processes of globalization are generating social tensions and magnifying stresses on natural environments.  Many subsistence and semi-subsistence communities have been suddenly confronted by the extension of markets and the backwash of globalization.  This has promoted uneven development, loss of community, disintegration of social structures which have supported economic mutualism and which have provided social safety nets.  In many cases too, natural resource bases and environments on which local communities depend for their livelihood are under threat, partly because systems of property rights and governance evolve slowly and externally imposed changes in these are often counterproductive.  This is illustrated by examples from Northeast India and China involving slash-and-burn agriculture.  Factors which may cause regional and social economic divergence in Asia in this globalizing world are discussed.  These include differential access to global knowledge and communication networks.  Urban and cosmopolitan communities probably stand to gain most from globalization processes.

Lloyd and Feldman's (this issue) continuing com-mentary on our recent target article and rejoinder (Ellis & Ketelaar, 2000; Ketelaar & Ellis, 2000) focuses on two overarching issues. First, Lloyd and Feldman claim that our description of the core metatheoretical assump-tions of ...

We investigated the bacterial gut microbiota from 32 colonies of wood-feeding termites, comprising four Microcerotermes species (Termitidae) and four Reticulitermes species (Rhinotermitidae), using terminal restriction fragment length polymorphism analysis and clonal analysis of 16S rRNA. The obtained molecular community profiles were compared statistically between individuals, colonies, locations, and species of termites. Both analyses revealed that the bacterial community structure was remarkably similar within each termite genus, with small but significant differences between sampling sites and/or termite species. In contrast, considerable differences were found between the two termite genera. Only one bacterial phylotype (defined with 97% sequence identity) was shared between the two termite genera, while 18% and 50% of the phylotypes were shared between two congeneric species in the genera Microcerotermes and Reticulitermes, respectively. Nevertheless, a phylogenetic analysis of 228 phylotypes from Microcerotermes spp. and 367 phylotypes from Reticulitermes spp. with other termite gut clones available in public databases demonstrated the monophyly of many phylotypes from distantly related termites. The monophyletic "termite clusters" comprised of phylotypes from more than one termite species were distributed among 15 bacterial phyla, including the novel candidate phyla TG2 and TG3. These termite clusters accounted for 95% of the 960 clones analyzed in this study. Moreover, the clusters in 12 phyla comprised phylotypes from more than one termite (sub)family, accounting for 75% of the analyzed clones. Our results suggest that the majority of gut bacteria are not allochthonous but are specific symbionts that have coevolved with termites and that their community structure is basically consistent within a genus of termites.

Host-parasite relationships are often characterized by the rapid evolution of parasite adaptations to exploit their host, and counteradaptations in the host to avoid the costs imposed by parasitism. Hence, the current coevolutionary state between a parasite and its hosts is predicted to vary according to the history of sympatry and local abundance of interacting species. We compared a unique reciprocal coevolutionary relationship of a fish, the European bitterling (Rhodeus amarus) and freshwater mussels (Unionidae) between areas of recent (Central Europe) and ancient (Turkey) sympatry. Bitterling parasitize freshwater mussels by laying their eggs in the gills of mussel and, in turn, mussel larvae (glochidia) parasitize the fish. We found that all bitterling from both regions avoided one mussel species. Preferences among other mussel species tended to be related to local mussel abundance rather than duration of sympatry. Individual fish were not consistent in their oviposition choices, precluding the evolution of host-specific lineages. Mussels were demonstrated to have evolved strong defenses to bitterling parasitism in the area of ancient sympatry, but have no such defenses in the large areas of Europe where bitterling are currently invasive. Bitterling avoided glochidia infection irrespective of the duration of sympatry.

Ribosome biogenesis, a central and essential cellular process, occurs through sequential association and mutual co-folding of protein–RNA constituents in a well-defined assembly pathway. Here, we construct a network of co-evolving nucleotide/amino acid residues within the ribosome and demonstrate that assembly constraints are strong predictors of co-evolutionary patterns. Predictors of co-evolution include a wide spectrum of structural reconstitution events, such as cooperativity phenomenon, protein-induced rRNA reconstitutions, molecular packing of different rRNA domains, protein–rRNA recognition, etc. A correlation between folding rate of small globular proteins and their topological features is known. We have introduced an analogous topological characteristic for co-evolutionary network of ribosome, which allows us to differentiate between rRNA regions subjected to rapid reconstitutions from those hindered by kinetic traps. Furthermore, co-evolutionary patterns provide a biological basis for deleterious mutation sites and further allow prediction of potential antibiotic targeting sites. Understanding assembly pathways of multicomponent macromolecules remains a key challenge in biophysics. Our study provides a ‘proof of concept’ that directly relates co-evolution to biophysical interactions during multicomponent assembly and suggests predictive power to identify candidates for critical functional interactions as well as for assembly-blocking antibiotic target sites.

The term 'co-evolution' originates in biology, meaning “the influence of closely associated species on each other in their evolution”. Ehrlich and Raven [10] first used the term  in reference to biological evolution when looking at the relationship between the patterns of evolution of plants and butterflies, stating that it describes the simultaneous, reciprocal evolution of interacting populations. Reciprocity is an element of co-evolutionary relationships stressed by all definitions in the literature. In biology, co-evolution refers to the change of a biological entity triggered by the change of a related entity [42]. Each entity exerts certain pressures and influences over the other, affecting the evolutionary trajectory of each.

Long-Lost Pollinators The rise of angiosperms in the Early Cretaceous (∼140 million years ago) was accompanied by coevolution of a variety of insects, including flies, bees, and wasps required for pollination. Ren et al. (p. 840 ; see the Perspective by Ollerton and Coulthard ) show that three families of scorpionflies had already evolved specialized mouth parts for feeding on the nectar of gymnosperms, as early as the Middle Jurassic (∼170 million years ago). The diversity and specialization of these insects and related plant structures suggests that they were also involved in pollination. These families died out later in the Cretaceous as angiosperms began to dominate.