Search results for "adaptation"
showing 10 items of 1775 documents
Botāniskā dārza sekciju "Augu daudzveidības pētījumi ex situ", "Augu selekcija un introdukcija" tēžu krājums (2018. gada 1. februāris, LU Botāniskais…
2018
Latvijas Universitātes 76. starptautiskās zinātniskā konferences Botāniskā dārza sekciju "Augu daudzveidības pētījumi ex situ" un "Augu selekcija un introdukcija" tēžu krājums. Sekciju sēdes notiek 2018. gada 1. februārī LU Botāniskajā dārzā Rīgā, Kandavas ielā 2.
Cooperation between Different CRISPR-Cas Types Enables Adaptation in an RNA-Targeting System
2021
CRISPR-Cas systems are immune systems that protect bacteria and archaea against their viruses, bacteriophages. Immunity is achieved through the acquisition of short DNA fragments from the viral invader’s genome.
Climate variability in forest management planning: The LIFE AForClimate project.
2018
Previous research experiences have shown that climate variability can play a relevant role in forest planning and management within a climate change scenario. In forest planning and management, yield tables, site quality indices, age classes, and rates of growth are some of the most frequently used parameters and tools. However, these ‘traditional’ methods do not include the influence of climate variability on forest growth over time, although it is one of the main influencing factors in tree growth. Changes in climate determine changes in thermo-pluviometric regimes that often have a marked influence on forest growth trends. Forest biomass, resilience, and carbon sequestration may be damag…
Trudności w szkolnej adaptacji dzieci sześcioletnich
2016
Jedną z istotniejszych idei ostatniej reformy edukacji w Polsce było obniżenie wieku obowiązku szkolnego z siedmiu do sześciu lat. We wrześniu 2015 roku wszystkie dzieci sześcioletnie rozpoczęły naukę w klasie pierwszej. Objęcie dzieci sześcioletnich obowiązkiem szkolnym wzbudziło wiele kontrowersji i liczne protesty społeczne, których efektem jest dzisiaj zapowiedź cofnięcia reformy. Celem opracowania jest próba oceny obecnej sytuacji - przedstawienie argumentów za i przeciw rozpoczęciu szkolnej edukacji dzieci sześcioletnich. Autorka zamieszcza także uwagi skierowane do najbliższego otoczenia dziecka - rodziców i nauczycieli, które mogą złagodzić trudy związane ze szkolną adaptacją.
AN ANALYSIS OF CONTINENT-WIDE PATTERNS OF SEXUAL SELECTION IN A PASSERINE BIRD
2006
Patterns of selection are widely believed to differ geographically, causing adaptation to local environmental conditions. However, few studies have investigated patterns of phenotypic selection across large spatial scales. We quantified the intensity of selection on morphology in a monogamous passerine bird, the barn swallow Hirundo rustica, using 6495 adults from 22 populations distributed across Europe and North Africa. According to the classical Darwin-Fisher mechanism of sexual selection in monogamous species, two important components of fitness due to sexual selection are the advantages that the most attractive males acquire by starting to breed early and their high annual fecundity. W…
Shoaling behaviour of fish under parasitism and predation risk
2008
Shoaling is a common antipredatory adaptation in several fish species. However, parasite infections may alter shoaling behaviour of fish by impairing fish sensory/motor systems and by reducing the net benefit of shoaling. In an experimental study, we investigated whether Diplostomum spathaceum (Trematoda) eye flukes alter shoaling behaviour of rainbow trout, Oncorhynchus mykiss, and if this has an interaction with predation risk. The parasite reduces the vision of fish by inducing cataract formation, which in previous studies has been shown to alter fish escape responses and crypsis. We found that the shoals of infected fish contained fewer individuals and they divided into separate groups …
Energy use, diapause behaviour and northern range expansion potential in the invasive Colorado potato beetle
2011
Summary 1. As organisms expand their range towards northern latitudes they will encounter selective factors like harsh winter conditions. The ability to cope with and adapt to harsh winters may depend on the variability and evolutionary potential of relevant traits. 2. One adaptation in insects is winter diapause. It is characterized by changes in physiology, behaviour or in both. Physiological changes include lowered metabolic rate that enhances survival by saving limited energy reserves during overwintering. Active behavioural changes like burrowing into the soil allow individuals to escape harsh conditions. 3. We examined variation in overwintering body mass, resting metabolic rate (CO2 …
Cryptic microgeographic variation in responses of larval Atlantic cod to warmer temperatures
2021
AbstractAlthough temperature is known to drive species dynamics and distributions, our understanding of the extent to which thermal plasticity varies within species is poor. Differences in plasticity can arise through local adaptation to heterogeneous environments, hybridization, and the release of cryptic genetic variation in novel environments. Here, wild Atlantic cod (Gadus morhua) from contrasting environments inside and outside of a fjord system in southern Norway spawned freely in a semi-natural laboratory environment, generating pure crosses and reciprocal hybrids. A common-garden rearing experiment of the larvae at 6°C, 9.5°C, and 13°C revealed cryptic genetic variation in thermal r…
2001
Duration from sowing to flowering is the most important trait influencing adaptation in pigeon pea (Cajanus cajan), but the inheritance of this trait has not been elucidated clearly. Crosses were made between two early (60 to 70d) and one late (160 to 170d) flowering pigeonpea genotype and F1, F2 and BC1 populations produced. These populations, comprising 60 to 100 parents, 30 F1, 400F2 and 40 to 50 BC1 plants, were grown under natural (mean13.4 hd-1) and artificially extended (to 15 hd-1) daylength and duration from sowing to first flowering recorded. Genetic analysis of the segregation ratios, supported by Chi-square tests, indicated that the duration from sowing to flowering in each of t…
1993
Lobsters and dolphins are adapted to aquatic life whereas the green woodpecker and the fly are adapted to aerial life. The way in which these organisms are constructed allows them to execute certain functions within certain environments. This is a first, simple definition of adaptation which describes:The evolutionary process of adjustment of an organism to its environment. This historical aspect will be discussed in subsequent chapters.The result of this process — the state of adaptation — or the form of an organism at a certain point in its history. This functional-structural aspect will be dealt with here.