Sökning: "Population size"

Visar resultat 1 - 5 av 766 avhandlingar innehållade orden Population size.

1. 1. Population size, viability and genetic diversity in the orchid Gymnadenia conopsea

   Författare :Linus Söderquist; Nina Sletvold; Sophie Karrenberg; Hans Jacquemyn; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; demography; extinction probability; genetic diversity; genetic rescue; genetic structure; Gymnadenia conopsea; orchid conservation; population viability; population size; Biology with specialization in Ecological Botany; Biologi med inriktning mot ekologisk botanik;

   Sammanfattning : In this thesis, I combined controlled crosses with genetic and demographic data to examine how a main conservation value indicator, population size, was associated with estimates of population viability. I focused on the still common, but decreasing, perennial orchid Gymnadenia conopsea at two spatial scales—locally on the island Öland, in SE Sweden, and regionally across Scandinavia. LÄS MER

3. 2. Finding fitness : empirical and theoretical explorations of inferring fitness effects from population-level SNP data

   Författare :Bea Angelica Andersson; Xiao-Ru Wang; Åke Brännström; Tanja Slotte; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; distribution of fitness effects; site frequency spectra; missing data filtering; downsampling; imputation; sample size; population structure; inbreeding; selfing; homozygosity; Arabidopsis; Pinus; DFE-alpha; SLiM; population genomics; adaptation; biology; biologi; evolutionär genetik; evolutionary genetics; populationsbiologi; Population Biology; molekylärbiologi; Molecular Biology; Genetics; genetik;

   Sammanfattning : The distribution of fitness effects (DFE) describes the likelihood that a new mutation has a specific effect on the fitness of an individual in a given population. The shape of the DFE is a result of several factors such as population size, mating system and selective environment, and can in turn influence the evolutionary potential of a species. LÄS MER

4. 3. Effects of size-dependent predation and competition on population and community dynamics

   Författare :Karin Nilsson; Lennart Persson; Volker Rudolf; Umeå universitet; []
   Nyckelord :size-structure; cannibalism; resource competition; predation; emergent facilitation; population regulation; population dynamics; overcompensation; density-dependence; cycles; zooekologi; Animal Ecology;

   Sammanfattning : Most animals grow substantially during their lifetime and change in competitive ability, predatory capacity and their susceptibility to predation as they grow. This thesis addresses the implications of this on regulation and dynamics within populations as well as between population interactions. LÄS MER

5. 4. Population Genetic Methods and Applications to Human Genomes

   Författare :Lucie Gattepaille; Mattias Jakobsson; Kevin Thornton; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Population genetics; Human evolution; Genetic diversity; Genetic differentiation; Adaptation; Population structure; Effective population size; Biology with specialization in Evolutionary Genetics; Biologi med inriktning mot evolutionär genetik;

   Sammanfattning : Population Genetics has led to countless numbers of fruitful studies of evolution, due to its abilities for prediction and description of the most important evolutionary processes such as mutation, genetic drift and selection. The field is still growing today, with new methods and models being developed to answer questions of evolutionary relevance and to lift the veil on the past of all life forms. LÄS MER

7. 5. Population viability analysis for plants : practical recommendations and applications

   Författare :Satu Ramula; Kari Lehtilä; Patrik Dinnétz; Esa Ranta; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; demography; matrix population models; population viability analysis; population growth rate; stochastic models; Biology; Biologi;

   Sammanfattning : Population viability analysis (PVA) is commonly used in conservation biology to predict population viability in terms of population growth rate and risk of extinction. However, large data requirements limit the use of PVA for many rare and threatened species. LÄS MER