Letteratura scientifica selezionata sul tema "Biology"

Kemampuan kuantitatif dibutuhkan calon guru biologi dalam memahami fenomena biologis. Hal pertama yang perlu dilakukan dalam menyelesaikan masalah ini adalah perlunya eksplorasi kondisi kecemasan matematika calon guru biologi. Penelitian ini bertujuan mengeksplorasi tingkat kecemasan matematika calon guru biologi dan perbedaannya berdasarkan gender dan angkatan masuk kuliah. Data dikumpulkan dengan menggunakan kuisioner AMAS (Abbreviated Math Anxiety Scale). Data dianalisis dengan menggunakan statistic deskriptif, uji anova satu arah, dan uji Kruskal-Wallis. Hasil penelitian menunjukkan calon guru biologi memiliki tingkat kecemasan matematika dan kecemasan belajar matematika berdasarkan angkatan dan gender berada pada kategori sedang. Sementara kecemasan evaluasi matematika berada pada kategori tinggi berdasarkan angkatan dan gender. Hasil penelitian juga menunjukkan tidak terdapat perbedaan kecemasan matematika, kecemasan belajar matematika, kecemasan atas evaluasi matematika berdasarkan gender dan angkatan. Hasil penelitian ini layak menjadi perhatian dalam pendidikan biologi bahwa perlu dikonstruksi suatu desain didaktis ataupun perubahan kurikulum yang mendorong integrasi dan interdisiplinari matematika dan biologi sehingga kecemasan matematika dapat berkurang. Quantitative ability is needed by prospective biology teachers in understanding biological phenomena. The first thing that needs to be done in solving this problem is the need to explore the condition of pre-service biology teachers’ mathematics anxiety. This study aims to explore the mathematics anxiety level of pre-service biology teachers and their differences by gender and cohort. Data were collected using the AMAS (Abbreviated Math Anxiety Scale) questionnaire. Data were analyzed using descriptive statistics, one-way ANOVA test, and Kruskal-Wallis test. The results showed that pre-service biology teachers had mathematics anxiety levels and mathematics learning anxiety based on cohort and gender were in the medium category. Meanwhile, mathematics evaluation anxiety is in the high category based on cohort and gender. The results also showed that there was no difference between mathematics anxiety, mathematics learning anxiety, anxiety over mathematics evaluation based on gender and cohort. The results of this study deserve attention in biology education that it is necessary to construct a didactic design or curriculum change that encourages integration and interdisciplinary mathematics and biology so that mathematics anxiety can be reduced.

Kemampuan kuantitatif dibutuhkan calon guru biologi dalam memahami fenomena biologis. Hal pertama yang perlu dilakukan dalam menyelesaikan masalah ini adalah perlunya eksplorasi kondisi kecemasan matematika calon guru biologi. Penelitian ini bertujuan mengeksplorasi tingkat kecemasan matematika calon guru biologi dan perbedaannya berdasarkan gender dan angkatan masuk kuliah. Data dikumpulkan dengan menggunakan kuisioner AMAS (Abbreviated Math Anxiety Scale). Data dianalisis dengan menggunakan statistic deskriptif, uji anova satu arah, dan uji Kruskal-Wallis. Hasil penelitian menunjukkan calon guru biologi memiliki tingkat kecemasan matematika dan kecemasan belajar matematika berdasarkan angkatan dan gender berada pada kategori sedang. Sementara kecemasan evaluasi matematika berada pada kategori tinggi berdasarkan angkatan dan gender. Hasil penelitian juga menunjukkan tidak terdapat perbedaan kecemasan matematika, kecemasan belajar matematika, kecemasan atas evaluasi matematika berdasarkan gender dan angkatan. Hasil penelitian ini layak menjadi perhatian dalam pendidikan biologi bahwa perlu dikonstruksi suatu desain didaktis ataupun perubahan kurikulum yang mendorong integrasi dan interdisiplinari matematika dan biologi sehingga kecemasan matematika dapat berkurang. Quantitative ability is needed by prospective biology teachers in understanding biological phenomena. The first thing that needs to be done in solving this problem is the need to explore the condition of pre-service biology teachers’ mathematics anxiety. This study aims to explore the mathematics anxiety level of pre-service biology teachers and their differences by gender and cohort. Data were collected using the AMAS (Abbreviated Math Anxiety Scale) questionnaire. Data were analyzed using descriptive statistics, one-way ANOVA test, and Kruskal-Wallis test. The results showed that pre-service biology teachers had mathematics anxiety levels and mathematics learning anxiety based on cohort and gender were in the medium category. Meanwhile, mathematics evaluation anxiety is in the high category based on cohort and gender. The results also showed that there was no difference between mathematics anxiety, mathematics learning anxiety, anxiety over mathematics evaluation based on gender and cohort. The results of this study deserve attention in biology education that it is necessary to construct a didactic design or curriculum change that encourages integration and interdisciplinary mathematics and biology so that mathematics anxiety can be reduced.

The characteristics of biology education students in lectures must be known to design better lectures. This study aims to analyze and determine students' characteristics in the Biology Education Study Program enrolled in basic biology courses at Universitas Labuhanbatu. This study employed a descriptive qualitative approach. A total of 30 first-semester biology education students were sampled from the population of first-semester biology education students. The tool for data collection was interviewed, and the strategy for data collection was the distribution of a questionnaire. The results of this study indicated that Biology Education students' characteristics enrolled in basic biology courses at Universitas Labuhanbatu were as follows: (1) Confidence in analyzing and understanding basic biology materials 47.20%, (2) Discipline 76.66%, (3) Honesty 48.66%, (4) Responsible 81.86%, and (5) Social care 69.66%. According to the results of this study, the student's character in the education system is one of the main aims for supporting a learning process in students so that they can become the next generation of individuals with excellent character souls.Abstrak Karakteristik mahasiswa pendidikan biologi dalam perkuliahan perlu diketahui guna mendesain perkuliahan yang lebih baik. Penelitian ini bertujuan untuk dapat menganalisis dan mengetahui karakter yang ada pada mahasiswa Program Studi Pendidikan Biologi pada mata kuliah biologi dasar di Universitas Labuhanbatu. Metode yang digunakan dalam penelitian adalah kualitatif deskriptif, Populasi yang digunakan adalah mahasiswa pendidikan biologi semester satu dengan pengambilan sampel total sampling yang berjumlah 30 mahasiswa pendidikan biologi, Instrumen dalam pengumpulan data yang digunakan adalah wawancara serta teknik dalam pengumpulan data dilakukan dengan pemberian angket. Hasil dalam penelitian ini memperoleh hasil bahwa karakter pada mahasiswa Pendidikan Biologi pada mata kuliah biologi dasar di Universitas Labuhanbatu memperoleh hasil sebagai berikut bahwa perolehan hasil data berupa: (1) Percaya diri menganalisis dan memahami materi biologi dasar 47,20%, (2) Disiplin 76,66%, (3) Kejujuran 48,66%, (4) Bertanggungjawab 81,86%, (5) Peduli sosial 69,66%. Hasil penelitian ini menunjukkan bahwa karakter pada mahasiswa dalam sistem pendidikkan merupakan salah satu prioritas yang sangat penting dalam menunjang suatu proses pembelajaran yang ada pada diri mahasiswa agar dapat menjadi generasi penerus yang terbentuk jiwa karakter yang baik.

A model is a key element in the daily practice of biologists, students, and teachers in learning biology. The existence of models, both physical and non-physical models, is crucial in learning implementation. Therefore, this article aims to explain the importance of the nature of model (NoM) in learning biology. This study used the literature review method. The literature review contains reviews, summaries, and the author's thoughts on several library sources. Thus, this study provides a description, summary, and information about the nature of models, especially in biology learning. Based on the literature study results, the study of the nature of models in the biology class is on the implementation of learning, teaching materials, and assessments. Models can be divided into types and characteristics that become alternative solutions to represent an object since biology studies a lot about living objects.Abstrak Model merupakan elemen kunci dalam praktik sehari-hari bagi para ahli biologi, siswa guru dalam pembelajaran biologi. Keberadaan model baik itu model fisik maupun nonfisik sangat penting dalam pelaksanaan pembelajaran. Oleh karena itu, tujuan dari penyusunan artikel ini adalah untuk menjelaskan pentingnya hakikat model dalam pembelajaran biologi. Kajian ini menggunakan metode studi kepustakaan (literature review). Studi kepustakaan berisi ulasan, rangkuman dan pemikiran penulis tentang beberapa sumber pustaka. Dengan demikian, kajian ini memberikan deskripsi, ringkasan dan informasi mengenai Nature of Models khususnya dalam pembelajaran biologi. Berdasarkan hasil studi literatur, kajian Nature of Models dalam kelas biologi terdapat pada pelaksanaan pembelajaran, bahan ajar, dan asesmen. Model dapat dibagi ke dalam tipe dan karakteristik yang menjadi solusi alternatif untuk merepresentasikan suatu objek, karena ilmu biologi banyak mempelajari tentang objek-objek kehidupan.

The purpose of this study was to examine prospective biology teachers’ perceptions and attitudes towards Instagram as a potential edutainment tool in biology learning. The study involved 87 prospective biology teachers from 4 public universities in Indonesia. Participants answered 15 closed questions and three open questions. Then data were analysed quantitatively and qualitatively. The results demonstrated that prospective biology teachers had highly positive perceptions of Instagram as an edutainment tool in biology learning. Respondents strongly agree that Instagram is easier to use than other learning platforms to create and upload learning content. Prospective biology teachers’ attitudes show that they agree to use Instagram as an edutainment tool in biology learning. The use of Instagram also has the potential to increase motivation, interaction, and creativity and is enjoyable in learning biology. Key words: Instagram, edutainment, perceptions, prospective biology teacher Abstrak. Tujuan dari penelitian ini adalah untuk menguji persepsi dan sikap calon guru biologi terhadap Instagram sebagai sarana edutainment yang potensial dalam pembelajaran biologi. Penelitian ini melibatkan 87 calon guru biologi dari 4 perguruan tinggi negeri di Indonesia. Partisipan menjawab 15 pertanyaan tertutup dan tiga pertanyaan terbuka. Kemudian data dianalisis secara kuantitatif dan kualitatif. Hasil penelitian menunjukkan bahwa calon guru biologi memiliki persepsi yang sangat positif terhadap Instagram sebagai sarana edutainment dalam pembelajaran biologi. Responden sangat setuju bahwa Instagram lebih mudah digunakan dibandingkan platform pembelajaran lain untuk membuat dan mengunggah konten pembelajaran. Sikap calon guru biologi menunjukkan bahwa mereka setuju untuk menggunakan Instagram sebagai sarana edutainment dalam pembelajaran biologi. Penggunaan Instagram juga berpotensi untuk meningkatkan motivasi, interaksi, dan kreativitas serta menyenangkan dalam pembelajaran biologi. Kata kunci: Instagram, edutainment, persepsi, calon guru biologi,

AbstrakPenelitian ini bertujuan untuk mengetahui pengaruh persepsi siswa pada mata pelajaran biologi, ekspektasi karir, dan regulasi diri terhadap hasil belajar biologi. Penelitian ini adalah penelitian ex-post facto dengan pendekatan jalur. Variabel eksogenus dalam penelitian ini adalah persepsi siswa pada mata pelajaran biologi dan ekspektasi karir, sedangkan variabel endogenusnya adalah regulasi diri dan hasil belajar biologi. Penelitian ini dilakukan di SMA Laboratorium Undiksha Singaraja pada siswa kelas X MIA dengan besar sampel 43 orang siswa. Data persepsi siswa pada mata pelajaran biologi, ekspektasi karir, dan regulasi diri dikumpulkan dengan angket, sedangkan data hasil belajar diperoleh dari nilai ulangan harian dan penilaian akhir semester. Data dianalisis dengan analisis jalur (pathway analysis). Hasil penelitian menunjukkan bahwa: 1) ada pengaruh yang signifikan persepsi siswa pada mata pelajaran biologi terhadap regulasi diri, 2) ada pengaruh yang signifikan ekspektasi karir terhadap regulasi diri 3) ada pengaruh langsung persepsi siswa pada mata pelajaran biologi terhadap hasil belajar biologi 4) ada pengaruh langsung ekspektasi karir terhadap hasil belajar biologi 5) ada pengaruh tidak langsung persepsi siswa terhadap hasil belajar biologi melalui regulasi diri, dan 6) ada pengaruh tidak langsung ekspektasi karir terhadap hasil belajar biologi melalui regulasi diri. Dengan demikian dapat disimpulkan bahwa peningkatan hasil belajar biologi dapat diupayakan dengan peningkatan persepsi siswa, ekspektasi karir, dan regulasi diri.Kata kunci: ekspektasi karir, hasil belajar biologi, regulasi diri, persepsi AbstractThis study aims to determine the effect of students' perceptions on biology subjects, career expectations and self-regulation towards biology learning outcomes. This research was an ex-post facto with pathway approach. Exogenous variables in this study were students' perceptions on biology subjects and career expectations, while endogenous variables were self-regulation and biology learning outcomes. This research was conducted at SMA Laboratorium Undiksha Singaraja in X Grade Natural Science students with total sample were 43 students. The data in this study were collected using student perception questionnaires on biology subjects, career expectations, and self-regulation. While learning outcomes data was collected from tests and final test. Data was analyzed by pathway analysis. The result show 1) there are effects of students 'perception on biology subject toward self-regulation, 2) there are effects of career expectation toward self-regulation, 3) there are direct effects of students' perception on biology subject toward biology learning outcomes, 4) there are direct effects of career expectations toward biology learning outcomes, 5) there are indirect effects of students' perception on biology subject toward biology learning outcomes through self-regulation, and 6) there are indirect effects of career expectations toward biology learning outcomes through self-regulation. So it can be conclude that the improvement of biology learning outcomes can be pursue from increase of student perception , carrer expectation, and self-regulation.Keywords : career expectations, learning outcomes, self-regulation, studens’ perception

Life-like behaviors such as fission, fusion and movement can be artificially re-created exploiting highly simplified protocell systems. This thesis is mainly focused on chemotaxis protocell systems and their integration with biological systems in order to show potential future applications. 1-Decanol droplets, formed in an aqueous medium containing decanoate at high pH, become chemotactic when a chemical gradient is placed in the external aqueous environment. We investigated the behavior of these droplets, their ability to transport and deposit living and non-living objects and to interface them with biofilms. To make the artificial system compatible with natural living systems we developed a partially hydrophobic alginate capsule as a protective unit that can be precisely embedded in a droplet, transported along chemical gradients and deposited. We developed a system that was able to transport: Escherichia coli, Bacillus subtilis and Saccharomyces cerevisiae. Both bacteria survived the transport. However, yeast survived but not in a consistent and repeatable way. Next, we evolved the system to transport human cell lines. We found that A549 cells survive encapsulation but not the transport. A549 cells are in fact very sensitive to toxic 1-decanol. We however found out that this cell line secretes compounds able to decrease the surface tension and to increase the capsule-droplet affinity. Finally we discuss future solutions for the effective transport of human cells.

Life-like behaviors such as fission, fusion and movement can be artificially re-created exploiting highly simplified protocell systems. This thesis is mainly focused on chemotaxis protocell systems and their integration with biological systems in order to show potential future applications. 1-Decanol droplets, formed in an aqueous medium containing decanoate at high pH, become chemotactic when a chemical gradient is placed in the external aqueous environment. We investigated the behavior of these droplets, their ability to transport and deposit living and non-living objects and to interface them with biofilms. To make the artificial system compatible with natural living systems we developed a partially hydrophobic alginate capsule as a protective unit that can be precisely embedded in a droplet, transported along chemical gradients and deposited. We developed a system that was able to transport: Escherichia coli, Bacillus subtilis and Saccharomyces cerevisiae. Both bacteria survived the transport. However, yeast survived but not in a consistent and repeatable way. Next, we evolved the system to transport human cell lines. We found that A549 cells survive encapsulation but not the transport. A549 cells are in fact very sensitive to toxic 1-decanol. We however found out that this cell line secretes compounds able to decrease the surface tension and to increase the capsule-droplet affinity. Finally we discuss future solutions for the effective transport of human cells.

Essential oils (EO) are plant secondary metabolites that are known for their fragrance and food flavour properties. They consist of a complex mixture of mono- and sesquiterpenes, phenyl propanoids and oxygenated compounds. EOs can be present in different plant organs and materials, and their storage is related to specialised secretory structures. The yield of EOs from plant raw materials by distillation or pressing may on average vary from 0.1 – 1%, thus restricting the major EO production to the plant group of aromatic plants. Due to their function as signalling compounds between different types of organisms and diverse biological systems, their general antimicrobial and antioxidative effects and medicinal activity, EOs offer a promising potential for future applications within the fields of agriculture, medicine, pharmaceutical industry and biotechnology.

Changed consumer demands and raised interest in natural product compounds, especially essential oils, have formed the basis for initiating the research project “Norwegian Herb Production (Norsk Urteproduksjon NUP)” to encourage the cultivation, processing, marketing and distribution of aromatic and medicinal plants. The production, composition and quality characteristics of EOs (yield and terpene composition) from chamomile, lemon balm, oregano, peppermint, sachalinmint, thyme and yarrow have been investigated in the project period between 1994-1998.

Much focus has been put on the application of solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS) for the analysis of EO volatiles from various aromatic and medicinal plants. SPME is a fast, solvent-free and non- destructive sample preparation technique where the analytes are extracted from fluid or solid matrices by headspace (HS) or direct immersion sampling (DI). Apart from EO isolation by common distillation, the applicability and sensitivity of the SPME fibre has made it feasible to carry out qualitative and semi-quantitative HS analyses of aromatic plants with regard to changes of EO metabolism during ontogenesis and plant development.

Based on NUP-results from field trials in the period between 1995-1996, the mint species peppermint (Mentha × piperita L.) and sachalinmint (Mentha sachalinensis (Briq.) Kudô) have been studied in detail (Papers B, D and E). Comparative analyses by applying distillation sampling and SPME have been carried out in order to study the advantages and disadvantages of both techniques (Papers B and E). It could be shown, that SPME offers a fast and reliable method for detecting quality-impact compounds from the p-menthane group (menthol, menthone, neomenthol, isomenthone and menthyl acetate). A distinct increase in the menthol/menthone ratio in the basipetal direction could be detected for peppermint and sachalinmint by applying SPME, thus revealing within-plant quality differences according to pharmacopeial requirements. Taking the increase of EO production from the vegetative to the generative growth stage into account, the harvest of mint plants in bloom will result in better EO yield and quality with regard to higher amounts of menthol.

When applying HS-SPME on complex EO volatile matrices such as known for yarrow (Achillea millefolium L.; Paper C), one might deal with fibre-partitioning effects of the different mono- and sesquiterpenes due to their physical and chemical properties. Despite these disadvantages, HS-SPME appears to be a sensitive extraction method for the screening of EO volatiles from complex sample matrices. Comparative analyses of volatiles from rose root rhizomes (Rhodiola rosea L.) have been carried out in order to characterize the rose-like odour compounds (Paper F). A total of 75 and 59 compounds have been identified by distillation sampling and HS-SPME, respectively, thus underscoring the excellent extraction properties and applicability of the SPME fibre.

Paper A gives a brief overview of EO biosynthesis and chemical structures, plant sources and methods of EO production. Before leading over to the main topic of HS-SPME applications by referring to numerous examples from the research work at The Plant Biocenter in the past 5 years, an introduction of solid-phase microextraction with regard to devices, procedures and extraction parameters is given.

The advantages and disadvantages of distillation vs. SPME are outlined on the background of comparative analyses of peppermint, chamomile, basil and dill. Furthermore, the utilization of HS-SPME for quantitative studies with regard to extraction time and analyte concentration is being highlighted. Examples for the screening of chemotypes (hops −Humulus lupulus L.) and cultivars (dill – Anethum graveolens L.) and ontogenetic studies are given (Mentha species; arnica −Arnica montana L.). Finally, the applicability of HS-SPME for the quality assessment of processed herbs (sweet basil −Ocimum basilicum L.) and phytomedicinal preparations (red coneflower – Echinacea purpurea L.) is being discussed.

The advantages of HS-SPME over classical distillation and headspace applications are impressive due to drastically reduced analysis time and will introduce new frontiers in plant volatile research with regard to secondary metabolism, plant-insect interactions and in vivo studies. The user-friendliness of operating SPME will initiate the development of future applications and equipment for the monitoring of volatiles for plant biological and environmental studies, extraction automation, on-site sampling and on-fibre storage of analytes.

Paper VI reprinted with kind permission of Elsevier, Sciencedirect, www.sciencedirect.com

The aims of this study were to investigate the effects of known environmental contaminants on defined behavioural variables in fish, and to discuss properties of these behavioural traits that make them useful as potential indicators of pollution.

In studying the effects of pollution, the resulting biochemical and physiological alterations are more commonly measured. However, effects of pollution can manifest itself at all levels of biological organisation, including behaviour. In this respect, behaviour can be considered a valid biomarker of pollution in that it is expected to be both susceptible to pollution and of high ecological significance, as it influences the fitness of the affected individuals.

This thesis is based on four individual studies, in which the threespine stickleback Gasterosteus aculeatus was used as a model species. Results from these studies show that antipredator behaviour, feeding behaviour, shoaling behaviour, bottom-dwelling behaviour and reproductive behaviour are all sensitive to exposure to sublethal concentrations of defined environmentally relevant chemicals.

The results showed that antipredator behaviour and fright response in threespine stickleback were impaired following exposure to sublethal concentrations of bis(tributyltin)oxide (TBTO). However, for some of the tested antipredator variables the effects were reversed after the ending of exposure. Further, it was shown that feeding motivation in fish exposed to butyl benzyl phthalate (BBP) and/or 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene (DDE) was increased in that exposed fish initiated feeding more often than the controls. Exposure to BBP also caused sticklebacks to aggregate into tight shoals and to spend more time at the bottom of the aquarium compared to the control fish.

The reported significant differences between the controls and BBPexposed fish with respect to feeding and shoaling behaviour were shown even though the levels of BBP were below the analytical detection limit. Different suggested explanations, for example, too high detection limit, or degradation to its BBP metabolites are given to this result.

17β-Oestradiol (E₂) exposed male sticklebacks started nest building later than non-exposed males, but there were no differences between exposed and control males with respect to the number of males that built nests. Further, the exposed males spent less time displaying paternal care compared to the control males, although there were no differences between the two groups in the number of performed courtship displays. Because of the significant effect upon some but not all reproductive behavioural traits, it was suggested that the different variables might vary in sensitivity, implying that a variety of variables should be studied in order to obtain a more reliable evaluation of the effects of pollution.

Chemicals can cause deleterious effects at one or more levels of biological organisation, from biochemical, physiological, individual, population and through to the ecosystem levels. In contrast to the established hypothesis that a pollutant affects the different biological levels in an escalating timedependent pattern, starting at the biochemical level, it is here suggested that biomarkers at the biochemical, physiological and behavioural levels often will respond early and simultaneously in the same individual.

Whereas some biochemical responses are specifically related to one class of exposure agents and thus may act as specific indicators of pollution, most behavioural traits may be altered in response to a variety of chemicals. One exception may be alterations in reproductive behaviour caused by endocrine disrupting chemicals, due to effects of the chemicals on hormones that result in immediate reproductive behavioural effects. In spite of the specific action of some biochemical biomarkers, they are often considered to be of little ecological relevance since many of them are not related to individual fitness.

In this thesis, it is argued that behavioural variables can be employed as useful and reliable biomarkers of environmental contamination. It is also important to focus on behaviour to map and quantify the resposes. However, to reliably evaluate the effects of pollution, behavioural variables should be used in association with biochemical and physiological traits. Moreover, optimal combination of results from laboratory and field experiments would enhance the ecological relevance of the study.

All papers reprinted with kind permission of Elsevier, sciencedirect.com

This thesis deals with effects of climate on tree growth of the dominating conifer species, Picea abies (L) Karst. (Norway spruce) and Pinus sylvestris L (Scots pine), in central Norway and Fennoscandia. Both species are sampled along major environmental gradients, i.e. altitude and oceanicity, and growth responses to climate, i.e. temperature and precipitation, are examined along these gradients. Additionally, time is considered as an environmental gradient and temporal responses are carefully deciphered. Special attention is given to large-scale climate oscillation and their effect on tree growth. In the individual papers the specific aims have been to:

1. identify climate variables (all seasons) with significant influence on radial tree growth of P. abies and P. sylvestris along major environmental gradients (Paper I-IV)

2. identify if and how the growth response to climate has changed through time along these gradients (Paper I-IV)

3. make interregional comparisons of P. sylvestris growth pattern across Fennoscandia from oceanic western Norway to continental eastern Finland (Paper III)

4. analyse to what degree large-scale circulation patterns of air masses are registered in regional tree growth of both P. abies and P. sylvestris (Paper I, III and IV)

5. discuss possible effects on radial tree growth of a predicted warmer climate (Paper I, III and IV)

When the study of this thesis was initiated, hardly any work had been carried out on how plant odour information was encoded by the olfactory RNs in heliothine moths. The method of gas chromatography linked to single cell recordings (GC-SCR) was employed and improved for identifying naturally occurring plant odorants that are detected by single RNs and can be considered as biologically relevant. Three species of the subfamily Heliothinae were included in this work, the two polyphagous H. virescens and H. armigera and the oligophagous H. assulta. The American H. virescens is geographically separated from the other two species. H. armigera and H. assulta are partly sympatric in Asia and Australia.

The aims of the thesis elucidated in Papers I-IV were as follows:

1. To identify plant produced volatiles detected by antennal RNs in the three species of the subfamily Heliothinae.

2. To elucidate whether the single RNs can be classified into distinct types according to their specificity.

3. To characterise the plant odour RN types by their molecular receptive ranges, sensitivity and specificity.

4. To compare the specificity of plant odour RN types across the three related species of Heliothinae, with the aim to reveal any differences in the peripheral olfactory system that may have evolved through evolution.

The bacterial origin of mitochondria from an ancient endosymbiosis is now widely accepted and the mitochondrial ancestor is generally believed to belong to the bacterial subdivision α-proteobacteria. The high fraction of mitochondrial proteins encoded in the nucleus has commonly been explained with a massive transfer of genes from the genome of the ancestral mitochondrion.

The aim of this work was to get a better understanding of the mitochondrial origin and evolution by comparative genomics and phylogenetic analyses on mitochondria and α-proteobacteria. To this end, we sequenced the genomes of the intracellular parasites Bartonella henselae and Bartonella quintana, the causative agents of cat-scratch disease and trench fever, and compared them with other α-proteobacteria as well as mitochondrial eukaryotes.

Our results suggest that the adaptation to an intracellular life-style is coupled to an increased rate of genome degradation and a reduced ability to accommodate environmental changes. Reconstruction of the α-proteobacterial ancestor and phylogenetic analyses of the mitochondrial proteome in yeast revealed that only a small fraction of the proteins used for mitochondrial functions could be traced to the α-proteobacteria. Furthermore, a substantial fraction of the mitochondrial proteins was of eukaryotic origin and while most of the genes of the α-proteobacterial ancestor have been lost, many of those that have been transferred to the nuclear genome seem to encode non-mitochondrial proteins.

Symbiosis is a widely common phenomenon in nature and has undoubtedly contributed to the evolution of all organisms on earth. Symbiotic associations can be of varying character, such as parasitic or mutualistic, but all imply a close relationship. To study the evolution of genomes of insect endosymbionts, we have sequenced the genomes of the mutualist Buchnera aphidicola from the aphid Schizaphis graminum (Sg) and the reproductive manipulator Wolbachia pipientis strain wRi from Drosophila simulans that show strikingly different evolutionary patterns.

The comparison between the genome of B.aphidicola (Sg) and the genome of B.aphidicola from the aphid Acyrthosiphon pisum (Ap), that are believed to have diverged 50 million years ago, revealed a perfect gene order conservation and loss of only 14 genes in either of the lineages. In contrast, the rate of nucleotide turnover is very fast probably due to relaxed selection and loss of DNA repair genes. The genomic stasis observed in Buchnera was attributed to the loss of repeats and of the gene recA.

In striking contrast to the genomes of B.aphidicola, a vast amount of repeats were found in the genome sequence of W.pipientis strain wMel. The comparison between the genomes of W.pipientis strain wRi and W.pipientis strain wMel shows that a lot of rearrangements have occurred since their divergence. The massive amount of repeats might stem from relaxed selection pressure but possibly also from selection to create variability via recombination.

Comparisons between pairs of genomes from closely related bacteria showed that the stability of gene order and content is connected to an intracellular lifestyle and indicated that homologous recombination between repeats is an important mechanisms for causing intrachromosomal rearrangements. Our studies show that the lifestyle of a bacterium to a great extent shapes the evolution of their genetic material and future capabilities to adapt to new environments.