نتایج جستجو برای: environmental variation

تعداد نتایج: 647156  

Journal: :American journal of epidemiology 2001
L E Mitchell J C Murray S O'Brien K Christensen

Previous studies suggest that the risk of nonsyndromic cleft lip with or without cleft palate (CL+/-P) and isolated cleft palate (CP) is influenced by genetic variation at several loci and that the relation between specific genetic variants and disease risk may be modified by environmental factors. The present study evaluated potential associations between CL+/-P and CP and two putative cleftin...

Journal: :International journal of epidemiology 2003
George Davey Smith Shah Ebrahim

Associations between modifiable exposures and disease seen in observational epidemiology are sometimes confounded and thus misleading, despite our best efforts to improve the design and analysis of studies. Mendelian randomization-the random assortment of genes from parents to offspring that occurs during gamete formation and conception-provides one method for assessing the causal nature of som...

The shape diversity among populations of Scartelaos tenuis (Day 1876) from five stations (194 specimens) in the Persian Gulf, Strait of Hormuz (Qeshm Island), and the Sea of Oman were investigated. The shape variation was assessed by geometric morphometrics, using 14 morphological landmarks. The two sexes were not distinguishable by the shape. Fish samples were classified into two distinct grou...

Journal: :Journal of personality and social psychology 1975
L Eaves H Eysenck

A biometrical-genetical analysis of twin data to elucidate the determinants of variation in extraversion and its components, sociability and impulsiveness, revealed that both genetical and environmental factors contributed to variation in extraversion, to the variation and covariation of its component scales, and to the interaction between subjects and scales. A large environmental correlation ...

2011
Michael Gerisch

Environmental variability is the main driver for the variation of biological characteristics (life-history traits) of species. Therefore, life-history traits are particularly suited to identify mechanistic linkages between environmental variability and species occurrence and can help in explaining ecological patterns. For ground beetles, few studies directly related species traits to environmen...

2014
Tarja Silfver Matti Rousi Elina Oksanen Heikki Roininen Judith Myers Patrick Tobin

A number of recent studies have shown that intraspecific genetic variation of plants may have a profound effect on the herbivorous communities which depend on them. However less is known about the relative importance of intraspecific variation compared to other ecological factors, for example environmental variation or the effects of herbivore damage. We randomly selected 22 Betula pendula geno...

2016
Patrick Tobin Judith Myers Tarja Silfver Elina Oksanen Heikki Roininen

A number of recent studies have shown that intraspecific genetic variation of plants may have a profound effect on the herbivorous communities which depend on them. However less is known about the relative importance of intraspecific variation compared to other ecological factors, for example environmental variation or the effects of herbivore damage. We randomly selected 22 genotypes from a lo...

Journal: :Evolution; international journal of organic evolution 2006
Robert H Kaplan Patrick C Phillips

Variation in fitness generated by differences in functional performance can often be traced to morphological variation among individuals within natural populations. However, morphological variation itself is strongly influenced by environmental factors (e.g., temperature) and maternal effects (e.g., variation in egg size). Understanding the full ecological context of individual variation and na...

Journal: :Proceedings. Biological sciences 2005
John M Drake

Global circulation models predict and numerous observations confirm that anthropogenic climate change has altered high-frequency climate variability. However, it is not yet well understood how changing patterns of environmental variation will affect wildlife population dynamics and other ecological processes. Theory predicts that a population's long-run growth rate is diminished and the chance ...

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