نتایج جستجو برای: ecological conditions

تعداد نتایج: 935412  

Journal: :The American naturalist 2000
Michael Doebeli Ulf Dieckmann

Evolutionary branching occurs when frequency-dependent selection splits a phenotypically monomorphic population into two distinct phenotypic clusters. A prerequisite for evolutionary branching is that directional selection drives the population toward a fitness minimum in phenotype space. This article demonstrates that selection regimes leading to evolutionary branching readily arise from a wid...

ژورنال: طلوع بهداشت یزد 2020

   Introduction: Human ecology examines the interactions between humans and the environment. Investigation of the human happiness and health requires a systematic study of the human life and ecosystem, which includes the physical and social environment of the human species.  Ecosystem is the basis of changes that occur in the biological, psychological, and social systems, because they happen in...

2015
Gary A Wellborn R Brian Langerhans

The tenet that ecological opportunity drives adaptive diversification has been central to theories of speciation since Darwin, yet no widely accepted definition or mechanistic framework for the concept currently exists. We propose a definition for ecological opportunity that provides an explicit mechanism for its action. In our formulation, ecological opportunity refers to environmental conditi...

In a wide range of the central boundaries of the Iranian plateau, encompassing an important part of the arid areas in Asia, the phenomenon of desertification is a long his tory. In this arid and waterless expanse, living conditions are fully dependent on access to water due to the supremacy of the Kavirs and deserts. The most important and oldest ways of obtaining water have been Qanat or Kariz...

A Shafiee

The Flora of Iran is very rich due to the diverse climatic and soil conditions in mdifferent ecological regions. Iran has around 10000 species of wild plant of which about 850 are considered being medicinally important. In the present work the phytochemistry of several Iranian medicinal plants and their possible usage will be discussed.

Journal: :Ecological applications : a publication of the Ecological Society of America 2009
Takehiro Sasaki Satoru Okubo Tomoo Okayasu Undarmaa Jamsran Toshiya Ohkuro Kazuhiko Takeuchi

The current growing body of evidence for diversity-disturbance relationships suggests that the peaked pattern predicted by the intermediate disturbance hypothesis (IDH) may not be the rule. Even if ecologists could quantify the diversity-disturbance relationship consistent with the IDH, the applicability of the IDH to land management has rarely been addressed. We examined two hypotheses related...

ژورنال: بوم شناسی آبزیان 2016

Different groups of animals show phenotypic characters, which have been resulted by the reductive phenomena. The examples are the absence of pigmentation; dwindle of eyes in some cave-living animals, and also the absence of scale in some fishes. These characters are often leaded to evolution of new species with special adaptation that is so called "Regressive evolution". The reductive phenomena...

Licorice (Glycyrrhiza glabra L.) as a strategic and highly valuable medicinal plant in Iran with numerous beneficial pharmaceutical properties contributes substantially to Iranian herbs exports. In the present study, a variation on the phytochemical and antioxidant activity of 25 populations of valuable and profitable medicinal plant of G. glabra was investigated. The climate variables and soil...

Ferula pseudalliacea (Bitter asafetida) is an endemic medicinal plant grown in the center of Iran, which is used in pharmaceutical industries. There is less report about its habitat characteristics and distribution in Iran. So, this research was conducted to study the effects of topography and soil properties on distribution of this species in Yazd Province, Iran in 2016 and 2017. Two habitats ...

Journal: :Psicothema 2008
Antonio González López María Amérigo Cuervo-Arango

The present study focuses mainly on the relationship between psychological constructs and ecological behaviour. Empirical analysis links personal values, ecological beliefs, consequences of environmental conditions, denial of ecological obligation, environmental control, personal norms and environment protection behaviour. Survey data from a path analysis of a Spanish sample of 403 individuals ...

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