Det bortkomne faget … Naturfaget tilbake i norsk grunnskole Synteserapport for prosjektet: Natur- og miljøfag etter Reform 97, en evaluering ut fra et elevperspektiv

Flere studier på 90-tallet viste at naturfagets stilling var svekket (Sjøberg 1994; Lie, Kjærnsli og Brekke 1997; Nergård 1994). I det intergrerte orienteringsfaget (o-fag) i barneskolen var naturfagets plass svak både i lærebøkene og i klasserommet. Den internasjonale TIMSS-undersøkelsen (Third International Mathematics and Science Study) viste at norske 13. åringer lå under eller rundt gjennomsnittet når det gjaldt kunnskaper i naturfag (Lie, Kjærnsli og Brekke 1997). Spesielt var resultatene dårlige i emner knyttet til fagområdene kjemi og fysikk. Videre viste TIMSS-undersøkelsen at Norge var etter Japan det landet som hadde størst forskjell mellom gutter og jenters holdninger til faget. Gjennom arbeidet med ny læreplan for grunnskolen ble naturfagets situasjon vektlagt og et viktig resultat er at en har fått et natur- og miljøfag på alle klassetrinn i grunnskolen, og spesielt i barneskolen. Dette er utvilsomt en av de større strukturelle endringene fra Mønsterplanen 87 (M87) til Reform 97 (R97). I dette prosjektet har vi valgt å evaluere natur- og miljøfaget på slutten av mellomtrinnet. Det er på barnetrinnet en har fått overgang fra det integrerte ”orienteringsfaget” til ”natur- og miljøfag”, den største endring for naturfaget med innføring av den ny læreplanen. Hovedmålet for prosjektet har vært: I hvilken grad har en nådd de faglige og holdningsmessige målsetninger Reform 97 setter for natur og miljøfaget? Dette er konkretisert i disse spørsmåla som er laget ut fra de felles måla i Læreplanen i natur- og miljøfag 97 (L97): · har jenter og gutter på lik linje utviklet kunnskaper, ferdigheter, engasjement, interesse og holdninger til alle deler av faget? · har elevene utviklet kunnskaper og ferdigheter i alle deler av faget som de kan anvende i dagliglivet og i forhold til samfunnet og miljøet rundt seg? · har elevene fått kunnskap og øvelse i naturvitenskaplig historie, tenke- og arbeidsmåte? · har elevene møtt et bredt spekter av arbeidsmåter og gjennom praktiske aktiviteter fått opplevelser, ferdigheter og erfaringer som kan anvendes i praktiske gjøremål

«Mamma, er du mest glad i telefonen eller i meg?» En kvalitativ studie av småbarnsforeldres erfaringer med og forhold til mobilbruk rundt barna

Det er gjort mye forskning på hvilke innvirkninger småbarnsforeldres mobilbruk kan ha på forelder-barn-interaksjoner og potensielt barns utvikling. Færre studier har undersøkt foreldres holdninger til mobilbruk og blant norske populasjoner er forskningen knapp. Vi gjennomførte en kvalitativ studie med semistrukturerte intervjuer for å undersøke hvilke holdninger småbarnsforeldre har rundt sin egen og andres mobilbruk når de er i lag med barna. Utvalget var 12 småbarnsforeldre (6 kvinner og 6 menn) med minst ett barn i alderen 0-5 år. Vi baserte oss på hovedtrekkene fra systematisk tekstkondensering hvor 3 fremtredende tema ble utforsket; 1) Viktigheten av å være bevisst egen mobilbruk og ulike måter å regulere bruken sin på, 2) fremtredende normer rundt mobilbruk, og 3) et ambivalensforhold til egen mobilbruk. Våre funn viser at småbarnsforeldre i stor grad prøver å være bevisst sin egen mobilbruk, men samtidig har et anstrengt forhold til regulering. De ville alltid prioritere barna og uttrykte bekymring for eventuelle konsekvenser av overdreven bruk. De fleste fortalte å være preget av felles oppfattede normer rundt mobilbruk, hva som var akseptabel og ikke-akseptabel bruk rundt barna, men at slike normer varierte etter ulike kontekstuelle faktorer. De fortalte om å være fordomsfulle men samtidig forståelsesfulle til andre foreldres mobilbruk. Vi fant også at majoriteten av deltakerne uttrykte et ambivalent forhold til egen mobilbruk, dens tilgjengelighet og dens mangfoldige bruksområder

Regressive evolution of the pelvic complex in stickleback fishes: a study of convergent evolution

Background: Regressive evolution of the pelvic complex has been observed in populations of three of five stickleback genera, Gasterosteus, Pungitius, and Culaea, from young freshwater habitats (<18,000 years old). It has been hypothesized to be selected for by ion limitation, lack of predation by fishes, and increased predation by large aquatic insects. Stickleback pelvic reduction is often caused by deletion mutations of the Pitx1 gene, which prevent its expression during pelvic development. Lack of Pitx1 expression may be partly compensated for by Pitx2, which is preferentially expressed on the left side of the body, causing the left pelvic vestige to be larger than the right. Thus, left-biased directional asymmetry of pelvic vestiges implicates null Pitx1 alleles. Aim: Review the geographical patterns of pelvic variation in the three stickleback genera and consider their implications for hypotheses regarding the genetics and evolution of pelvic reduction in the Gasterosteidae. Data: We review published data on pelvic reduction and add previously unpublished information from populations in Scotland and Norway. Methods: We assign individual stickleback to one of three pelvic phenotypes – normal, vestigial, and lost pelvis – and explore the distribution of these three broad classes among populations. We study bilateral symmetry of the pelvis by scoring pelvic phenotypes on the left and right sides. Results: Pelvic reduction is rare in sticklebacks and occurs only in fresh water. Sticklebacks with pelvic reduction tend to occur in the western and northern parts of their ranges in Eurasia and North America, but this pattern is less evident for the ninespine stickleback. Pelvic phenotype frequency distributions within populations differ among stickleback genera. The vestigial pelvic phenotype dominates in many populations of Gasterosteus aculeatus, rarely in Pungitius, and never in Culaea inconstans. In Culaea, the lost and normal pelvic phenotypes are often dimorphic, but a vestigial pelvis is rare. This dimorphism does not occur in the other two genera. Monomorphism of the lost pelvic phenotype does not occur in Gasterosteus, and is rare in the other two genera. Asymmetry of pelvic vestiges is common in all three genera, but left-larger directional asymmetry predominates only in Gasterosteus. This bias could be due to the suggested regulatory mutation in the Pitx1 gene and/or mutations in downstream targets of Pitx1, and suggests involvement of other genes for pelvic reduction in the other genera.2014-08-3

Spatio-temporal patterns in pelvic reduction in threespine stickleback (Gasterosteus aculeatus L.) in Lake Storvatnet

Questions: The pelvic girdle with associated spines is an integrated anti-predator defence apparatus, and is assumed to protect against piscivores in the threespine stickleback. On the other hand, it might be costly to produce the pelvic apparatus in ion-poor and mineralchallenging freshwater. Hypothesis: Stickleback with a reduced pelvic apparatus should use more shelter and be more nocturnal, avoiding predation risk. In contrast, stickleback with a well-developed pelvic apparatus should have reduced mortality during ontogeny in encounters with piscivores and thus have a longer expected lifespan. Given these two life-history strategies, we expect assortative mating as a result of divergent selection. Organism: Marine and freshwater threespine stickleback (Gasterosteus aculeatus L.). Places and times: Two representative ancestral marine populations and 36 freshwater populations in northwestern Norway (Lake Storvatnet, the main focus of the study, and three lakes downstream of it). Material was collected from 2006 to 2009. Analytical methods: We categorized nominal pelvic apparatus development (CPS morphs) in all fish, and measured metrics associated with these categories in a subsample. We also studied temporal, spatial, and habitat variation in the distribution of pelvic morphs in Lake Storvatnet. In this population, and downstream populations, we contrasted the detailed pelvic morphology with the measured genetic diversity (microsatellites), also estimating gene flow. In Lake Storvatnet, we tested for genetic divergence and signs of potential build-up of reproductive isolation via assortative mating among the observed nominal categories of pelvic reduction (CPS). Results: Pelvic reduction was seen only in Lake Storvatnet, where more than 50% of fish had a reduced pelvis. The distribution of pelvic morphs was stable over time and did not differ between habitats. The proportion of fish with pelvic reduction decreased with age. Freshwater stickleback tended to have a smaller pelvis than marine fish. The Lake Storvatnet stickleback were genetically differentiated from the downstream Lake Gjerhaugsvatn population, and both of these were different from the marine populations, with little gene flow among populations. No apparent genetic structure was found between CPS morphs within Lake Storvatnet. However, genetic factorial correspondence axes were significantly correlated with pelvic principal component axes in Lake Storvatnet, suggesting some phenotype × genetic association. Conclusion: The weak association between phenotypes and genetic structure observed in this study may reflect the build-up of early steps of reproductive isolation. Given time, such mechanisms may lead to the evolution of assortative mating, which may drive adaptive pelvic morphs (niche peaks), further resulting in genetically divergent populations and pelvic morphs

Selective agents in the adaptive radiation of Hebridean sticklebacks

Question: What selective agents underpin the adaptive radiation of threespine sticklebacks (Gasterosteus aculeatus) on the Outer Hebridean island of North Uist? Hypothesis: The chief agents of selection for lateral plate number and pelvic score are predatory trout, the availability of dissolved ions, or an interaction of both. Methods: Adult threespine sticklebacks were collected from 26 lochs on North Uist. Fish were killed, stained, and scored for lateral plate number and pelvic score. We also measured the pH and concentration of dissolved calcium and phosphorous of each loch. We assessed the abundance of predatory trout in a subset of lochs by ‘fly fishing’ using a lure that mimicked the appearance of sticklebacks. Results: Dissolved calcium and phosphorous predicted stickleback lateral plate number and pelvic score, while trout abundance failed to predict either. Attack rates by trout on stickleback lures were higher in lochs with higher numbers of trout, with high water clarity, and at higher water temperatures. Our findings implicate a role for the bioavailability of dissolved ions in selection for reduced lateral plate number and pelvic score evolution, with indirect evidence for an effect of trout predation on the adaptive radiation of stickleback populations on North Uist

Population transcriptomics reveals weak parallel genetic basis in repeated marine and freshwater divergence in nine-spined sticklebacks

Abstract The degree to which adaptation to similar selection pressures is underlain by parallel vs. non-parallel genetic changes is a topic of broad interest in contemporary evolutionary biology. Sticklebacks provide opportunities to characterize and compare the genetic underpinnings of repeated marine-freshwater divergences at both intra- and interspecific levels. While the degree of genetic parallelism in repeated marine-freshwater divergences has been frequently studied in the three-spined stickleback (Gasterosteus aculeatus), much less is known about this in other stickleback species. Using a population transcriptomic approach, we identified both genetic and gene expression variations associated with marine-freshwater divergence in the nine-spined stickleback (Pungitius pungitius). Specifically, we used a genome-wide association study approach, and found that ~1% of the total 173,491 identified SNPs showed marine-freshwater ecotypic differentiation. A total of 861 genes were identified to have SNPs associated with marine-freshwater divergence in nine-spined stickleback, but only 12 of these genes have also been reported as candidates associated with marine-freshwater divergence in the three-spined stickleback. Hence, our results indicate a low degree of interspecific genetic parallelism in marine-freshwater divergence. Moreover, 1,578 genes in the brain and 1,050 genes in the liver were differentially expressed between marine and freshwater nine-spined sticklebacks, ~5% of which have also been identified as candidates associated with marine-freshwater divergence in the three-spined stickleback. However, only few of these (e.g., CLDND1) appear to have been involved in repeated marine-freshwater divergence in nine-spined sticklebacks. Taken together, the results indicate a low degree of genetic parallelism in repeated marine-freshwater divergence both at intra- and interspecific levels.Peer reviewe

Three-spined stickleback armour predicted by body size, minimum winter temperature and pH

Similar phenotypes evolve under equivalent environmental conditions through parallel evolution. Because they have repeatedly invaded and adapted to new freshwater environments, the three-spined stickleback (Gasterosteus aculeatus) offers a powerful system for understanding the agents of selection in nature that drive parallel evolution. Here we examine the ecological and environmental variables responsible for morphological variation in three-spined stickleback populations across its European range. We collected fish from 85 populations, encompassing much of the European latitudinal range of the species and including lowland rivers and lakes, coastal lagoons, and moorland ponds. We measured biotic and environmental variables at all sites along with morphological traits for 2,358 individuals. Using an information theory approach, we identified body size, minimum average winter temperature and pH as primary predictors of stickleback armour evolution, challenging current hypotheses for stickleback morphological diversification and demonstrating the fundamental role played by body size and scaling in mediating responses to selection. Stickleback lateral plate phenotype represents a potentially powerful tool for monitoring change in climate variables across the northern temperate region

A phylogenomic perspective on diversity, hybridization and evolutionary affinities in the stickleback genus Pungitius

Hybridization and convergent evolution are phenomena of broad interest in evolutionary biology, but their occurrence poses challenges for reconstructing evolutionary affinities among affected taxa. Sticklebacks in the genus Pungitius are a case in point: evolutionary relationships and taxonomic validity of different species and populations in this circumpolarly distributed species complex remain contentious due to convergent evolution of traits regarded as diagnostic in their taxonomy, and possibly also due to frequent hybridization among taxa. To clarify the evolutionary relationships among different Pungitius species and populations globally, as well as to study the prevalence and extent of introgression among recognized species, genomic data sets of both reference genome-anchored single nucleotide polymorphisms and de novo assembled RAD-tag loci were constructed with RAD-seq data. Both data sets yielded topologically identical and well-supported species trees. Incongruence between nuclear and mitochondrial DNA-based trees was found and suggested possibly frequent hybridization and mitogenome capture during the evolution of Pungitius sticklebacks. Further analyses revealed evidence for frequent nuclear genetic introgression among Pungitius species, although the estimated proportions of autosomal introgression were low. Apart from providing evidence for frequent hybridization, the results challenge earlier mitochondrial and morphology-based hypotheses regarding the number of species and their affinities in this genus: at least seven extant species can be recognized on the basis of genetic data. The results also shed new light on the biogeographical history of the Pungitius-complex, including suggestion of several trans-Arctic invasions of Europe from the Northern Pacific. The well-resolved phylogeny should facilitate the utility of this genus as a model system for future comparative evolutionary studies.Peer reviewe

Population genetic dynamics of three-spined sticklebacks (Gasterosteus aculeatus) in anthropogenic altered habitats

In industrialized and/or agriculturally used landscapes, inhabiting species are exposed to a variety of anthropogenic changes in their environments. Genetic diversity may be reduced if populations encounter founder events, bottlenecks, or isolation. Conversely, genetic diversity may increase if populations adapt to changes in selective regimes in newly created habitats. With the present study, genetic variability of 918 sticklebacks from 43 samplings (21.3 ± 3.8 per sample) at 36 locations from cultivated landscapes in Northwest Germany was analyzed at nine neutral microsatellite loci. To test if differentiation is influenced by habitat alterations, sticklebacks were collected from ancient running waters and adjacent artificial stagnant waters, from brooks with salt water inflow of anthropogenic and natural origin and adjacent freshwater sites. Overall population structure was dominated by isolation by distance (IBD), which was significant across all populations, and analysis of molecular variance (AMOVA) revealed that 10.6% of the variation was explained by river catchment area. Populations in anthropogenic modified habitats deviated from the general IBD structure and in the AMOVA, grouping by habitat type running/stagnant water explained 4.9% of variation and 1.4% of the variation was explained by salt-/freshwater habitat. Sticklebacks in salt-polluted water systems seem to exhibit elevated migratory activity between fresh- and saltwater habitats, reducing IBD. In other situations, populations showed distinct signs of genetic isolation, which in some locations was attributed to mechanical migration barriers, but in others to potential anthropogenic induced bottleneck or founder effects. The present study shows that anthropogenic habitat alterations may have diverse effects on the population genetic structure of inhabiting species. Depending on the type of habitat change, increased genetic differentiation, diversification, or isolation are possible consequences