Search results for "vuodenajat"

"Vaahterasta putoo helikoptereita" : ensimmäisen luokan oppilaan käsitteiden hallinta

1997

Adaptation and ecological speciation in seasonally varying environments at high latitudes: Drosophila virilis group

2022

Living in high latitudes and altitudes sets specific requirements on species’ ability to forecast seasonal changes and to respond to them in an appropriate way. Adaptation into diverse environmental conditions can also lead to ecological speciation through habitat isolation or by inducing changes in traits that influence assortative mating. In this review, we explain how the unique time-measuring systems of Drosophila virilis group species have enabled the species to occupy high latitudes and how the traits involved in species reproduction and survival exhibit strong linkage with latitudinally varying photoperiodic and climatic conditions. We also describe variation in reproductive barriers…

Dependence of Arctic char (Salvelinus alpinus L.) on littoral and pelagic energy sources in a subarctic lake, Saanajärvi

2007

Seasonality of Ixodes ricinus and Ixodes trianguliceps tick on the bank vole (Myodes glareolus) and on vegetation in Central Finland

2014

Children's Types of Physical Activity and Sedentary Behaviour in Day Care Environment during Outdoor Play over the Course of Four Seasons in Finland

2019

What makes John move? Outdoor play physical environmental factors changing a child’s activity from sedentary to physically active: longitudinal mixed…

2021

Children’s low physical activity levels call for an investigation of what can promote activity for excessively sedentary children. The purpose of this longitudinal mixed-method case study in an early childhood education (ECE) environment was to observe one sedentary child’s free outdoor playtime in four seasons and determine the physical environmental factors changing his activity from sedentary to physically active. Systematic observation of video material and quantitative analysis were used to identify the most sedentary individual of the one ECE group. The child was named “John”. Qualitative analysis of John’s video material showed that during the four seasons he spent an average of 25% …

Home range and movements of the Saimaa ringed seal (Phoca hispida saimensis Nordq.)

2010

Uhanalaisen saimaannorpan (Phoca hispida saimensis Nordq.) spatiaalinen käyttäytymisekologia on puutteellisesti tunnettua: liikkumista on tutkittu jonkin verran avovesiajalla, mutta talviajalta vastaavia tutkimuksia ei ole tehty. Saimaannorpan on osoitettu olevan paikkauskollinen karvanvaihto- ja pesintäalueille, ja sen on ehdotettu olevan paikkauskollinen myös läpi vuoden. Tässä tutkimuksessa pyrittiin selvittämään saimaannorpan elinpiirin kokoa, liikkumista ja paikkauskollisuutta läpi vuoden VHF-radiotelemetrian avulla. Seurantajaksoilla 1999-2000 ja 2006-2007 seurattiin yhteensä viittä yksilöä lähetinten kiinnittämisestä toukokuussa niiden tippumiseen saakka (marraskuu-huhtikuu). Kesä- j…

Seasonal changes in European whitefish muscle and invertebrate prey fatty acid composition in a subarctic lake

2019

Ambient light and temperature show extreme seasonal variation in subarctic lakes due to the midnight sun period in summer and cold polar night period in winter. These changes have clear impacts on fish feeding and reproduction cycles, potentially affecting the fatty acid (FA) composition of muscle. Despite extensive research into fish FA over recent decades, we know little about intra‐annual changes of fish FA profile and content. We studied intra‐annual changes in the FA profile (mol%) and content (mg g‐1 dry weight) of sexually mature European whitefish (Coregonus lavaretus) muscle in a large and deep subarctic lake located in northern Fennoscandia. We collected fish, zooplankton, and ben…

Plasticity in Photoperiodism : Drosophila montana Females Have a Life-Long Ability to Switch From Reproduction to Diapause

2022

Photoperiodic reproductive diapause is an essential part of female life cycle in several insect species living on high latitudes, where overwintering in reproductive stage involves high risks for survival and progeny production. The sensitive period (SP), during which photoperiodic cues can trigger the switch from direct development to diapause, can last from a few hours or days after emergence to the entire life span of females. Moreover, in some species, sexually mature females can enter post-reproductive diapause as a response to decreasing day length and/or temperature. We studied the duration of SP for diapause induction and the females’ ability to enter post-reproductive diapause at s…

Development of Henneguya zschokkei (Myxozoa: Myxosporea) actinospores in oligochaetes and plasmodia in whitefish Coregonous lavaretus

2013

The aim of this study was to describe the life cycle of H. zschokkei by observing the development of actinospores in oligochaete and the morphological development of H. zschokkei cysts in whitefish. Laboratory observation of seasonal occurrence of actinospores sampled from oligochaetes from RTKL Tervo Fish Farm revealed 6 types of actinospores from collective groups of Triactinomyxon, Raabeia and Aurantiactinomyxon in 2010, and 3 types of actinospores in 2011. Both years showed similar patterns with the release of actinospores peaking in both summer (June and July) and winter (January and February) times. The infection experiment was not successful in infecting Coregonus lavaretus with myxo…