Ecosystem engineer Dotaz Zobrazit nápovědu
The higher termites (Termitidae) are keystone species and ecosystem engineers. They have exceptional biomass and play important roles in decomposition of dead plant matter, in soil manipulation, and as the primary food for many animals, especially in the tropics. Higher termites are most diverse in rainforests, with estimated origins in the late Eocene (∼54 Ma), postdating the breakup of Pangaea and Gondwana when most continents became separated. Since termites are poor fliers, their origin and spread across the globe requires alternative explanation. Here, we show that higher termites originated 42-54 Ma in Africa and subsequently underwent at least 24 dispersal events between the continents in two main periods. Using phylogenetic analyses of mitochondrial genomes from 415 species, including all higher termite taxonomic and feeding groups, we inferred 10 dispersal events to South America and Asia 35-23 Ma, coinciding with the sharp decrease in global temperature, sea level, and rainforest cover in the Oligocene. After global temperatures increased, 23-5 Ma, there was only one more dispersal to South America but 11 to Asia and Australia, and one dispersal back to Africa. Most of these dispersal events were transoceanic and might have occurred via floating logs. The spread of higher termites across oceans was helped by the novel ecological opportunities brought about by environmental and ecosystem change, and led termites to become one of the few insect groups with specialized mammal predators. This has parallels with modern invasive species that have been able to thrive in human-impacted ecosystems.
- MeSH
- deštný prales MeSH
- ekosystém MeSH
- fylogeneze MeSH
- fylogeografie metody MeSH
- genom mitochondriální MeSH
- Isoptera genetika růst a vývoj MeSH
- mitochondriální DNA genetika MeSH
- mitochondrie genetika MeSH
- rozšíření zvířat MeSH
- zavlečené druhy MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Parameters characterizing the structure of the decomposer food web, biomass of the soil microflora (bacteria and fungi) and soil micro-, meso- and macrofauna were studied at 14 non-reclaimed 1- 41-year-old post-mining sites near the town of Sokolov (Czech Republic). These observations on the decomposer food webs were compared with knowledge of vegetation and soil microstructure development from previous studies. The amount of carbon entering the food web increased with succession age in a similar way as the total amount of C in food web biomass and the number of functional groups in the food web. Connectance did not show any significant changes with succession age, however. In early stages of the succession, the bacterial channel dominated the food web. Later on, in shrub-dominated stands, the fungal channel took over. Even later, in the forest stage, the bacterial channel prevailed again. The best predictor of fungal bacterial ratio is thickness of fermentation layer. We argue that these changes correspond with changes in topsoil microstructure driven by a combination of plant organic matter input and engineering effects of earthworms. In early stages, soil is alkaline, and a discontinuous litter layer on the soil surface promotes bacterial biomass growth, so the bacterial food web channel can dominate. Litter accumulation on the soil surface supports the development of the fungal channel. In older stages, earthworms arrive, mix litter into the mineral soil and form an organo-mineral topsoil, which is beneficial for bacteria and enhances the bacterial food web channel.
- MeSH
- ekosystém MeSH
- hornictví * MeSH
- potravní řetězec * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
For decades, biologists have relied on software to visualize and interpret imaging data. As techniques for acquiring images increase in complexity, resulting in larger multidimensional datasets, imaging software must adapt. ImageJ is an open-source image analysis software platform that has aided researchers with a variety of image analysis applications, driven mainly by engaged and collaborative user and developer communities. The close collaboration between programmers and users has resulted in adaptations to accommodate new challenges in image analysis that address the needs of ImageJ's diverse user base. ImageJ consists of many components, some relevant primarily for developers and a vast collection of user-centric plugins. It is available in many forms, including the widely used Fiji distribution. We refer to this entire ImageJ codebase and community as the ImageJ ecosystem. Here we review the core features of this ecosystem and highlight how ImageJ has responded to imaging technology advancements with new plugins and tools in recent years. These plugins and tools have been developed to address user needs in several areas such as visualization, segmentation, and tracking of biological entities in large, complex datasets. Moreover, new capabilities for deep learning are being added to ImageJ, reflecting a shift in the bioimage analysis community towards exploiting artificial intelligence. These new tools have been facilitated by profound architectural changes to the ImageJ core brought about by the ImageJ2 project. Therefore, we also discuss the contributions of ImageJ2 to enhancing multidimensional image processing and interoperability in the ImageJ ecosystem.
Digital health information systems (DHIS) are increasingly members of ecosystems, collecting, using and sharing a huge amount of personal health information (PHI), frequently without control and authorization through the data subject. From the data subject's perspective, there is frequently no guarantee and therefore no trust that PHI is processed ethically in Digital Health Ecosystems. This results in new ethical, privacy and trust challenges to be solved. The authors' objective is to find a combination of ethical principles, privacy and trust models, together enabling design, implementation of DHIS acting ethically, being trustworthy, and supporting the user's privacy needs. Research published in journals, conference proceedings, and standards documents is analyzed from the viewpoint of ethics, privacy and trust. In that context, systems theory and systems engineering approaches together with heuristic analysis are deployed. The ethical model proposed is a combination of consequentialism, professional medical ethics and utilitarianism. Privacy enforcement can be facilitated by defining it as health information specific contextual intellectual property right, where a service user can express their own privacy needs using computer-understandable policies. Thereby, privacy as a dynamic, indeterminate concept, and computational trust, deploys linguistic values and fuzzy mathematics. The proposed solution, combining ethical principles, privacy as intellectual property and computational trust models, shows a new way to achieve ethically acceptable, trustworthy and privacy-enabling DHIS and Digital Health Ecosystems.
Biological diversity is of fundamental importance for the functioning of all natural and human-engineered ecosystems and, by extension, for the ecosystem services that Nature provides, free of charge, for human society. Biodiversity is most frequently quantified as the number of species. Microbial diversity has driven the evolution of all life on Earth as well as the nutrient cycles, which are key for the operation of the biosphere. The review explains basic concepts of diversity studies such as structural, generic, genetic or functional diversity and describes evolution of taxonomy.
Geneticky modifikované organizmy jsou deřmovány legislativně jako živé entity, schopné množení a/nebo přenosu dědičného materiálu, u kterých byl dědičný materiál změněn přidáním nebo odebráním části nukleové kyseliny. Legislativou EU, a tedy i českou jsou tyto organizmy klasi%kovány jako rizikové, zatímco jiné produkty šlechtitelství, třeba získané navozenou mutagenezí, jsou považovány za bezpečné, stejně jako organizmy přenesené z jiných ekosystémů. Český zákon je založen na vedení seznamů uživatelů a organizmů pro jednotlivé způsoby nakládání. Zápis do seznamu se rovná povolení a je třeba o něj žádat ministerstvo životního prostředí. Žadatel musí mj. provést hodnocení rizika spojeného se zamýšleným nakládáním s geneticky modi%kovaných organizmem. Modi%kované organizmy s sebou nesou jistá ekologická rizika. Zdravotní rizika jsou spojena většinou pouze s mikroorganizmy. Modifikované organizmy určené pro potravinářství se podrobně kontrolují jak co do shody s nemodifikovanou kontrolou, tak z hlediska zdravotní bezpečnosti nových bílkovin vnesených modi%kací. Podrobnost a nákladnost kontrol se blíží kontrolám nových léčiv. Značení potravin podle evropské a české legislativy je motivováno psychologií spotřebitelů a nemá zdravotní význam. Vede k absurditám, ale současně svůj psychologický účel neplní. Proto orgány EU přijaly řadu opatření k nápravě, protože současná situace by vedla k hlubokému zaostávání Evropy.
Genetically modified organisms are deřmed by law as entities capable of replication and/or transmission of hereditary materiál that had been altered by the insertion or removal of a DNA fragment. By the EU legal regulation as well as by the Czech law, such organisms are considered risky whereas other products of breeding, though obtained by, e.g., induced mutagenesis, are claimed as safe. Organisms transferred from other ecosystems are also considered safe. The Czech law on the use of genetically modified organisms is based on registers of users and organisms for specific use. Application for the registration that is valid as an approval should be submitted to the Ministry of Environment. The applicant is obliged to present the risk assessment of the particular use of genetically modi%ed organisms. Genetically modi%ed organisms are connected with certain risk to ecology, however health risky are brought about almost exclusively by microorganisms. Modi%ed organisms used for food production are thoroughly tested for substantial equivalency with standard crops and with respect to health parameters of the protein(s) netyly introduced due to genetic modification. Detail tests as well as their cost are Glose to the testing of new drugs. European as well as Czech rules for food labelling are motivated by the psychology of consumers rather than by health impact. They result to absurdities but do not meet the task of public psychology. This is why the EU authorities are looking for measures to change the present situation that other wise would bring Europe well behind the developed countries.
BACKGROUND: Quaternary climate fluctuations are an engine of biotic diversification. Global cooling cycles, such as the Last Glacial Maximum (LGM), are known to have fragmented the ranges of higher-latitude fauna and flora into smaller refugia, dramatically reducing species ranges. However, relatively less is known about the effects of cooling cycles on tropical biota. RESULTS: We analyzed thousands of genome-wide DNA markers across an assemblage of three closely related understorey-inhabiting scrubwrens (Sericornis and Aethomyias; Aves) from montane forest along an elevational gradient on Mt. Wilhelm, the highest mountain of Papua New Guinea. Despite species-specific differences in elevational preference, we found limited differentiation within each scrubwren species, but detected a strong genomic signature of simultaneous population expansions at 27-29 ka, coinciding with the onset of the LGM. CONCLUSION: The remarkable synchronous timing of population expansions of all three species demonstrates the importance of global cooling cycles in expanding highland habitat. Global cooling cycles have likely had strongly different impacts on tropical montane areas versus boreal and temperate latitudes, leading to population expansions in the former and serious fragmentation in the latter.
- MeSH
- biologická evoluce * MeSH
- databáze jako téma MeSH
- druhová specificita MeSH
- ekosystém * MeSH
- fylogeneze MeSH
- fylogeografie MeSH
- jednonukleotidový polymorfismus genetika MeSH
- ledový příkrov * MeSH
- nadmořská výška MeSH
- počítačová simulace MeSH
- populační genetika MeSH
- pravděpodobnost MeSH
- sekvence nukleotidů MeSH
- zeměpis MeSH
- zpěvní ptáci růst a vývoj MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Papua Nová Guinea MeSH
V současné době již existuje několik druhů transgenních ryb. Každý z nich se vyznačuje určitou výhodou oproti svým divoce žijícím příbuzným. Především rychlejší růst a velikost transgenních ryb z nich dělají velké lákadlo pro chovatele. Legislativa komerční chov takovýchto ryb ve většině zemí zatím zakazuje.Možný dopad transgetiních ryb na jejich konzumenty a celý ekosystém je předmětem studií. Přesto je v Americe již povolen prodej a chov transgenních „svítících" ryb.
Currently, there are already several species of transgenic fish available. Each of the transgenic species has some specific advantage in comparison to its wild living peer. Particularly faster growth and larger size make transgenic fish attractive for fish farmers. However, commercial breeding of these species is legislatively forbidden in the majority of countries. Potential impact ot transgenic tish on their consumers and the whole ecosystem is a subject of studies. Nevertheless, the breeding and the sale of transgenic GloFish (glowing fish) is already allowed in America.
Parasitoids acting as biocontrol agents provide farmers with valuable ecosystem services, but are sensitive to insecticides applied against pests. Besides lethal effects of insecticides, sublethal effects observed among survivors may further influence parasitoids' performance. However, information on sublethal effects is scattered across case studies, without a quantitative synthesis and evaluation of generality of respective data. We conducted an analysis of 85 primary empirical datasets to quantify sublethal effects of insecticide application on two key parameters of parasitoid fitness, offspring production and proportion of females among offspring (i.e. sex ratio). To create a direct link to existing agricultural practices, we primarily focused on studies in which parasitoids were exposed to field-recommended concentrations of insecticides. Insecticide-exposed females produced substantially fewer and more male-biased offspring, accounting for an average of about 28% cumulative loss in parasitoid reproductive capacity per generation. The magnitude of sublethal effects was significantly affected by insecticide mode of action, with broad-spectrum insecticides being particularly harmful to parasitoid reproductive performance. Transgenic crops and toxins derived from such plants were generally associated with weaker sublethal effects than majority of synthetic insecticides. Nevertheless, species responses, even to the same insecticides and transgenic crops, showed high variability, cautioning against extrapolating results from individual studies to a wider range of species. Overall, our results indicate that sublethal side-effects on parasitoid reproductive performance represent a significant and widespread cost of insecticides that should explicitly be taken into account when evaluating their harmfulness. Linking laboratory results to field situations remains a key challenge for future research.
- MeSH
- geneticky modifikované rostliny účinky léků růst a vývoj parazitologie MeSH
- Hymenoptera účinky léků růst a vývoj MeSH
- insekticidy toxicita MeSH
- interakce hostitele a parazita účinky léků MeSH
- LD50 MeSH
- rozmnožování * MeSH
- sexuální faktory MeSH
- zemědělské plodiny účinky léků růst a vývoj parazitologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
