The information continuum model of evolution

Most biologists agree that evolution is contingent on inherited information shaped by natural selection. This apparent consensus could be taken to indicate agreement on the forces shaping evolution, but vivid discussions reveal divergences on how evolution is perceived. The predominant Modern Synthesis (MS) paradigm holds the position that evolution occurs through random changes acting on genomic inheritance. However, studies from recent decades have revealed that evolutionary inheritance also includes DNA-methylation, RNA, symbionts, and culture, among other factors. This has fueled a demand of a broader evolutionary perspective, for example from the proponents of the Extended Evolutionary Synthesis (EES). Despite fundamental disagreements the different views agree that natural selection happens through dissimilar perpetuation of inheritable information. Yet, neither the MS, nor the ESS dwell extensively on the nature of hereditary information. We do - and conclude that information in and of itself is immaterial. We then argue that the quality upon which natural selection acts henceforth is also immaterial. Based on these notions, we arrive at the information-centric Information Continuum Model (ICM) of evolution. The ICM asserts that hereditary information is embedded in diverse physical forms (DNA, RNA, symbionts etc.) representing a continuum of evolutionary qualities, and that information may migrate between these physical forms. The ICM leaves theoretical exploration of evolution unrestricted by the limitations imposed by the individual physical forms wherein the hereditary information is embedded (e.g. genomes). ICM bestows us with a simple heuristic model that adds explanatory dimensions to be considered in the evolution of biological systems.publishedVersio

Relative transcript quantification by Quantitative PCR: Roughly right or precisely wrong?

BACKGROUND: When estimating relative transcript abundances by quantitative real-time PCR (Q-PCR) we found that the results can vary dramatically depending on the method chosen for data analysis. RESULTS: Analyses of Q-PCR results from a salmon louse starvation experiment show that, even with apparently good raw data, different analytical approaches [1,2] may lead to opposing biological conclusions. CONCLUSION: The results emphasise the importance of being cautious when analysing Q-PCR data and indicate that uncritical routine application of an analytical method will eventually result in incorrect conclusions. We do not know the extent of, or have a universal solution to this problem. However, we strongly recommend caution when analysing Q-PCR results e.g. by using two or more analytical approaches to validate conclusions. In our view a common effort should be made to standardise methods for analysis and validation of Q-PCR results

Drift diving by hooded seals (Cystophora cristata) in the Northwest Atlantic Ocean

This work was funded through the Atlantic Seal Research Programme, International Governance Programme (GBS and MOH), the Greenland Institute of Natural Resources (ARA), and a CFI grant to YFW. The authors also acknowledge the support of the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) in the completion of this study. MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions (LB).Many pinniped species perform a specific dive type, referred to as a ‘drift dive’, where they drift passively through the water column. This dive type has been suggested to function as a resting/sleeping or food processing dive, and can be used as an indication of feeding success by calculating the daily change in vertical drift rates over time, which reflects the relative fluctuations in buoyancy of the animal as the proportion of lipids in the body change. Northwest Atlantic hooded seals perform drift dives at regular intervals throughout their annual migration across the Northwest Atlantic Ocean. We found that the daily change in drift rate varied with geographic location and the time of year and that this differed between sexes. Positive changes in buoyancy (reflecting increased lipid stores) were evident throughout their migration range and although overlapping somewhat, they were not statistically associated with high use areas as indicated by First Passage Time (FPT). Differences in the seasonal fluctuations of buoyancy between males and females suggest that they experience a difference in patterns of energy gain and loss during winter and spring, associated with breeding. The fluctuations in buoyancy around the moulting period were similar between sexes.Publisher PDFPeer reviewe

Production, mortality, and infectivity of planktonic larval sea lice, Lepeophtheirus salmonis (Krøyer, 1837): current knowledge and implications for epidemiological modelling

Current sea louse models attempt to estimate louse burdens on wild and cultured salmon by predicting the production and distribution of lice larvae and estimating the risk of transmission. While physical characteristics of water bodies and weather can be accurately modelled, many aspects of sea lice biology require further parameterization. The aims of this review are (i) to describe current knowledge regarding the production, mortality, and infectivity of planktonic sea lice larvae and (ii) to identify gaps in knowledge and suggest research approaches to filling them. Several major gaps are identified, and those likely to have the greatest impact on infection levels are (i) egg production, viability and hatching success, (ii) predation in plankton and (iii) copepodid infectivity profiles. A key problem identified in current parameter estimates is that they originate from a number of sources and have been determined using a variety of experimental approaches. This is a barrier to the provision of “best” or consensus estimates for use in modelling. Additional and more consistent data collection and experimentation will help to fill these gaps. Furthermore, coordinated international efforts are required to generate a more complete picture of sea louse infections across all regions experiencing problems with sea lice

Opportunities for advancing ecosystem-based management in a rapidly changing, high latitude ecosystem

Unprecedented and rapid changes are ongoing in northern high latitude, marine ecosystems, due to climate warming. Species distributions and abundances are changing, altering both ecosystem structure and dynamics. At the same time, human impacts are increasing. Less sea ice opens for the opportunity of more petroleum-related activities, shipping and tourism. Fisheries are moving into previously unfished habitats, targeting more species across more trophic levels. There is a need for ecosystem-based fisheries management (EBFM) and ecosystem-based management (EBM) to take the rapid, climate driven changes into account. Recently, there has been much development in qualitative, semi-quantitative, and quantitative scientific approaches to support EBFM and EBM. Here, we present some of these approaches, and discuss how they provide opportunities for advancing EBFM and EBM in one high-latitude system, namely the Barents Sea. We propose that advancing EBFM and EBM is more about adding tools to the toolbox than replacing tools, and to use the tools in coordinated efforts to tackle the increasing complexities in scientific support to management. Collaborative and participatory processes among stakeholders and scientists are pivotal for both scoping and prioritizing, and for efficient knowledge exchange. Finally, we argue that increasing uncertainty with increasing complexity is fundamental to decision making in EBFM and EBM and needs to be handled, rather than being a reason for inaction or irrelevance.publishedVersio

Disentangling the key drivers of salmon louse Lepeophtheirus salmonis fecundity using multiyear field samples

Planktonic salmon louse Lepeophtheirus salmonis salmonis larvae produced at sal - mon farms spread to and infect both wild and farmed salmonids. Understanding and forecasting the production and distribution of these larval stages from farms is critical to aquaculture management. However, model forecasts are based on available data and therefore include parameters with limited empirical support. This investigation examined salmon louse fecundity with a focus on batch egg clutch size by collecting lice from farmed Atlantic salmon Salmo salar at multiple farms and from wild Atlantic salmon and sea trout S. trutta captured at field sites throughout Norway. The data were analyzed with mixed effects models and total length of female lice was identified as the primary determinant of clutch size. Further analysis revealed that female louse total length is partially explained by temperature at sampling. However, if the temperature at sampling is spatially or temporally disconnected from rearing temperature, it may not be possible to predict the total length of a louse using temperature. The fecundity investigation further found that 66% of female lice on farmed salmon were sexually mature, and 10% of these were not egg-bearing. In comparison, 73% of adult female lice on sea trout were sexually mature, and 40% of these were not egg-bearing. Our results indicate that salmon louse production forecasts would be improved by incorporating female louse sexual maturity and a clutch size parameter that is related to total length of female lice.publishedVersio

Hvor allsidig er bardehvalenes kosthold?

Gjengitt med tillatelse fra Universitetsbiblioteket i TromsøBardehvaler er store og tallrike og viktige predatorer i Barentshavet. Hvor beiter de, hva beiter de på og hva gjør de når bestander av byttedyr kollapser? For å lære mer om dette observerte vi bardehvaler under Havforskningsinstituttets økosystemtokt i Barentshavet. Resultatene tyder på en variert diett nord i Barentshavet

Development of the salmon louse Lepeophtheirus salmonis parasitic stages in temperatures ranging from 3 to 24°C

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