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Faculty of Biological and Environmental Sciences


Recent Submissions

  • Toivonen, Hannele (2023)
    The heating season 2022–2023 was exceptional in Finland due to the electricity crisis. Electricity saving became a hot topic in public discussion, and households reduced their electricity consumption significantly. This study focuses on the changes that happened in detached house dwellers’ everyday routines: how detached house dwellers’ electricity consumption-related practices changed, and why they changed during the electricity crisis. Understanding how changes happen in electricity consumption-related practices is especially important in the ongoing era of the energy transition. The study is situated within social scientific energy research and the theoretical framework is based on the theories of practice. The study draws on six in-depth interviews of Finnish detached house dwellers living in the Helsinki metropolitan area or the Uusimaa region. The interviews focused on changes in detached house dwellers’ electricity consumption-related practices during the electricity crisis. The results of the study indicate that some practices are more flexible than others. The interviewed households controlled and replaced the material elements of some practices, especially heating devices of indoor spaces and household water. A new practice of monitoring electricity prices was adopted by households with spot-price electricity contracts, who also time-shifted some of their practices based on the price. The interviewed households focused especially on reducing electricity consumption which they considered ‘extra’ consumption. Some of the households also challenged some comfort-related norms and conventional ways of conducting certain practices. Electricity price was stated as the primary reason to change electricity consumption-related practices. Some of the interviewees also mentioned recommendations for saving electricity impacting their practices. It is interpreted that new meanings of scarcity were attached to electricity during the crisis. Electricity became a more visible element of practices, which led the interviewed households to reflect on their electricity consumption on a general level
  • Yrjölä, Veikko (2023)
    While the effects of agricultural land use on biodiversity are beginning to unravel in Europe and North America, Africa remains poorly studied. Biodiversity in a broad sense provides ecosystem functioning and services, whose importance has become obvious to humankind in the quickly changing modern world. In Ghana, the practice of mango farming continues to grow in popularity due to suitable climate and potential source of livelihood. With increased demand and production of mango, natural habitats, namely savannahs, are being converted to plantations. The effects of such habitat conversion on local biodiversity are unknown for most taxa, thus providing an interesting study system for biodiversity research. Given the direct relation between functional diversity and ecosystem services, in this work I compare the taxonomic and functional diversity of ground-living spiders between mango orchards and savannah. I chose spiders (Arthropoda; Araneae) as model organisms as they critically contribute to several ecosystem services, such as biological pest control and nitrogen cycling, while being ubiquitous and abundant, thus easy to collect in the field. Spiders were captured with pitfall traps from six mango and four savannah areas in the Northern region of Ghana. A total of 424 individuals and 53 (morpho)species were identified and counted. Additionally, six morphological and four ecological traits were quantified for each (morpho)species. With these data, I calculated taxonomic richness and evenness, functional richness, dispersion, and evenness, and beta diversity of the different assemblages in the R environment. These metrics were then compared between spiders collected from mango orchards and savannah. Mango orchards showed lower taxonomic and functional evenness than savannah, contrary to all other alpha diversity measures. The two habitat types share many of the same diversity of ground-living spiders, but species and traits are distributed less evenly in mango orchards due to incomplete niche differentiation between species. Both taxonomic and functional beta diversity were significantly different between habitat types indicating that mango orchards sustain a similar richness of species as savannah, but the species composition is different. In conclusion, mango orchards have the potential to conserve some aspects of the original diversity, but species composition and the way species interact are substantially different. We should strive to find the best practices to produce mango without radically changing the natural biodiversity patterns.
  • Holopainen, Katariina (2023)
    At visual threshold, the vision relies on catching incident photons. The ultimate limitation of visual sensitivity arises from the quantal nature of light. At night, the uncertainty of photon arrivals differs fundamentally from daylight conditions, where photon flow can be considered continuous, and sets an absolute physical limitation to visual sensitivity. Visual sensitivity has been postulated to be affected by circadian physiological changes. Here, we have shown, that absolute visual sensitivity is under circadian control in light decrement, or quantal shadow, detection in mice. A behavioural visual task of finding a dark stimulus spot was conducted in a white water maze across several background light intensities leading gradually from clearly visible light to darkness. The percentage of correct choices in the task as a function of light intensity was used to measure visual sensitivity, which was remarkably higher nocturnally. Another parameter affecting visual sensitivity was shown to be the decrement size. Mice were more successful in finding the bigger decrements of the three spatial scales used, as well as succeeding in the task better at night. This finding suggests that visual sensitivity is affected by the absolute number of photons, or more precisely, the absolute number of missing photons in contrast to photons of the background illumination.
  • Tornikoski, Taru (2023)
    Social behaviour can be divided into neutral, positive, and negative, depending on the social context. Positive social behaviour involves affiliative prosocial interactions that encourage social and emotional cohesion. Rat (Rattus norvegicus) is a globally distributed common rodent species adapted to living near humans. Rats are intelligent and social animals with reciprocal prosocial behaviour. However, research on the social behaviour of rats is concentrated in laboratory settings and very little is known about the social behaviour of free-living rats. Rats arouse strong prejudice in humans and are considered aggressive. Despite a long history of coexistence, there are still strong conflicts between humans and rats. In this study, I used camera trap data to investigate the types of social behaviour in free-living rats and the time allocation of different behaviours. I investigated how the rats' behaviour is divided into socially neutral or positive and negative behaviour in relation to the total time spent on the behaviour. I also investigated the types of social behaviour that occur when rats approach each other and the frequencies of these different behavioural models. For the behavioural analyses, I used data-driven ethograms that I made and the behavioural analysis software BORIS. I found that the majority (over 96.2 %) of the social behaviour of the free-living rats in my study population was neutral or positive behaviour as measured by the duration of the behaviour categories. I also found that the most significant proportion of social behavioural models in rats was socially neutral or positive. Agonistic behavioural models were rare and occurred mostly between adults. In contrast, rats exhibited a moderate amount of prosocial behaviour, particularly in the form of food sharing and muzzle touching. My study brings new information to the limited previous research on the behaviour of free-living rats. The results suggest that most of the social behaviour in free-living rats would be neutral or positive behaviour, and agonistic behaviour in rats would be relatively rare. To the best of my knowledge, this work is the first study to analyse the social behaviour of free-living rats from camera trap data. Objective research data on the social behaviour of rats may mitigate prejudice against rats and attitudes towards rats may become more positive. This can mitigate conflict between humans and rats and promote peaceful coexistence. This work can be used as a pilot for future studies. The information this work provides can also be used, for example, to educate people about their attitudes towards rats.
  • Uriona Egia, Garazi (2023)
    The ends of eukaryotic chromosomes are formed by a special heterochromatic structure, the telomere, which is essential to guarantee chromosome stability. Telomeres protect chromosomic ends from DNA degradation, repair, and recombination events. However, they are difficult to replicate due to their repetitive and heterochromatic nature, which hinder DNA replication fork progression. In yeast, Mph1 helicase promotes replication fork regression, cross-over suppression during homologous recombination (HR), and telomere maintenance. Moreover, Mte1 is a D-loop binding protein involved in response to DNA damage and maintenance of telomere length, which interacts with Mph1, thereby stimulating its regression capacity as a helicase and fork. Thus, the Mte1-Mph1 complex is recruited to stressed telomeres. Mte1 also shares a domain of unknown function, DUF2439, with Rad51 and Rdh54. Additionally, Esc2 protein is involved in the regulation of DNA damage through template switch (TS) recombination, preventing HR events caused by Mph1. This thesis aimed to uncover the potential roles and interactions of proteins involved in telomere maintenance, such as Mph1, Mte1, Esc2 and Rdh54, for which two main assays were conducted: (1) Telomere Stability assay, consisting of Tus/Ter barrier based on the high-affinity binding of the E. coli protein, Tus, to specific DNA sequence called Ter; (2) Template Switching assay, focused on the capability of the proteins in reconstructing a functional LYS2 gene by TS. The obtained results demonstrated that (1) the absence of Rdh54 enhances replication fork regression, (2) Mte1 and Esc2 show opposite roles in telomere maintenance, (3) the interaction between Mte1 and Rad51 plays a crucial role in ensuring telomere stability and nuclear foci formation, (4) Mph1 and Mte1 promote cell survival through the break-induced replication (BIR) pathway. Further studies should assess the plausible interaction between Mph1 and Rdh54 proteins and characterize the function and interplay of the proteins involved in TS.