Search results for "LEVEL"
showing 10 items of 3465 documents
COGNITIVE DEPTH OF TEACHING AND LEARNING PROCESS IN BIOLOGY FROM 7TH TILL 9TH GRADE
2018
From OECD PISA Science test results presented in 2016 shows that in Latvia only 3,4% of students performance is in accordance to the 5th and 6th performance level (higher order cognitive skills (HOCS) measured), which is below OECD average. In Latvia from 2016 started Curriculum Development and Implementation project, which one of the priorities is student’s ability to apply HOCS (higher order cognitive skills) to improve these results. The development of deeper thinking (cognitive activity) is one of the most advanced skills in all subjects, including biology. In order to reduce the risks, it is necessary to analyze introducing new reforms the opportunities for students to develop HOCS th…
Differences in allozyme patterns between Diaphanosoma brachyurum and Diaphanosoma mongolianum, as revealed in Central European populations
1995
Recent taxonomic revisions in the genus Diaphanosoma have made the uncertainty in species discrimination with morphological characters obvious. Therefore species characterization on a genetic basis seems to be required. Here we examined the genetic structure of two Diaphanosoma mongolianum populations and three Diaphanosoma brachyurum populations in Central Europe by allozyme electrophoresis. A genetic differentiation between both species was evident. 5 out of 9 tested loci carried diagnostic alleles. Both species differed in their habitat choice: D. mongolianum was adapted to higher trophic levels than D. brachyurum. Co-occurrence was observed in a eutrophic lake. Populations sampled from …
New insights into the diversity dynamics of Triassic conodonts
2013
International audience; In this paper, we examine the diversity trends and the evolutionary patterns of Triassic conodonts through a newly powered large-scale data-set compiled directly from the primary literature. Paleodiversity dynamics analyses have been undertaken by working at the species level and using a system of time units based on biozone subdivisions for a fine temporal level resolution. The role of heterogeneous duration of taxa in diversity estimates has been evaluated through the probabilistic profiles. Results reveal three different stages in the diversity behaviour of Triassic conodonts from standing metrics delimited by two inflections at the mid-Anisian and mid-Carnian. Su…
Response of a shallow Mediterranean lake to nutrient diversion: does it follow similar patterns as in northern shallow lakes?
2005
Summary 1. In view of the paucity of data on the response of warm shallow lakes to reductions in nutrient loading, this paper presents a long-term limnological data set to document changes in the food-web of a shallow Mediterranean lake (Lake Albufera, Valencia, Spain) that has experienced reductions in phosphorus (P) (77%) and nitrogen (N) (24%) loading following sewage diversion. 2. Nine years after sewage diversion, P concentration in the lake was reduced by 30% but remained high (TP = 0.34 mg L−1), although the mean water retention time in the lake was only 0.1 years. Nitrate concentrations did not significantly change, probably because the lake continued to receive untreated effluents …
A quantitative review of the lifestyle, habitat and trophic diversity of dinoflagellates (Dinoflagellata, Alveolata)
2012
This study reviews the trends in the lifestyle, habitat distribution and trophic diversity of the 2377 described species of dinoflagellates (Dinophyceae). Most of the dinoflagellates inhabit marine waters, whereas 17% of the total species have colonized continental waters. Dinoflagellates are dominated by planktonic species, while benthic forms represented 8% of the species. From the total number of species, 49% are heterotrophic (devoid of plastids), while 51% of the species have been reported with plastids (that does not strictly imply autotrophy). All the basal dinoflagellates (ellobiopsids, Duboscquodinida, Syndiniales) are heterotrophic, with the exception of a few Noctilucales (Spatul…
Seasonality of coastal phytoplankton in the Baltic Sea: Influence of salinity and eutrophication
2005
Abstract In this study long-term (1984–2001) phytoplankton and physico-chemical monitoring data representing different salinity regimes of the Baltic Sea were compiled from HELCOM, national and regional databases. The aim was to define seasonal succession patterns of phytoplankton in seven different areas of the Baltic sea, characterised by different salinity, climate, and trophic conditions and to delineate a set of phytoplankton community indicators that are independent of season and salinity, but indicative of trophic status of different coastal areas. The cluster analysis of the combined data set resulted in eight phytoplankton community types, common for all locations, and characterise…
Lipid-rich zooplankton subsidise the winter diet of benthivorous Arctic charr (Salvelinus alpinus) in a subarctic lake
2013
Summary Generalist fish species commonly act as important links between littoral and pelagic habitats and food-web compartments in lakes. However, diet and habitat links may depend significantly on seasonal availability of, and qualitative differences between, littoral and pelagic prey and on fish size. Despite increasing interest in food-web dynamics, little is known about the seasonal changes in, or qualitative differences between, littoral and pelagic trophic pathways supporting generalist fish species in high-latitude lakes. We used stomach contents together with analyses of stable carbon and nitrogen isotopes and fatty acids to study the winter and summer diet of generalist Arctic char…
Biodiversity and technological potential of wild lactic acid bacteria from raw cows' milk
2009
To study lactic acid bacteria (LAB) biodiversity and to evaluate their potential for use in dairy applications, eight raw cows' milk batches were sampled from five dairy factories located in different areas of the Trentino region during winter and summer milkings. A total of 370 (Gram-positive and catalase-negative) isolates were first molecularly analysed by means of randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). After strain differentiation (124 profiles), LAB were genetically identified at species level. The most frequently isolated LAB were lactococci, enterococci and streptococci. Lactobacilli, leuconostocs and pediococci were found at low levels. All strains …
Composition and Trophic Structure of Detrital Food Web in Ant Nest Mounds of Formica aquilonia and in the Surrounding Forest Soil
1998
Community composition and food web structure of soil decomposer biota in relation to various habitat properties were compared between upper parts of red wood ant (Formica aquilonia) nest mounds and the adjacent forest soil. For a description of trophic structure of the decomposer community in the two habitats, soil decomposers were classified into 14 trophic groups. Classification of the taxa into three habitat preference categories resulted in a clear division of the fauna into either soil or nest specialists, relatively few taxa falling between these two groups. A large majority of the nest specialists belonged to a non-myrmecophilous soil decomposer fauna so far largely overlooked in stu…
The trophic structure of the pipefish community (Pisces: Syngnathidae) from a western Mediterranean seagrass meadow based on stable isotope analysis
2004
Syngnathus abaster andSyngnathus typhle (Pisces: Syngnathidae) from a dense Cymodocea nodesa meadow in the western Mediterranean Stagnone di Marsala (Italy) were studied using δ13N and δ15N analysis. Because of the presence of these two species in the same habitat and the specialized parental care by the male, the effect of species and sex on the isotopic composition was also studied to investigate the different feeding strategies between and within species.S. abaster andS. typhle exhibited enriched13C and15N values throughout the sampling period (mean ±SE, δ13C =−10.5±1.8‰ and−10.8±2.0‰, δ15N=11.9±0.7‰ and 10.6±1.0%., respectively), suggesting that these species receive their energy mainly…