منابع مشابه
The ghost sex-life of the paedogenetic beetle Micromalthus debilis
Genetic and sexual systems can be evolutionarily dynamic within and among clades. However, identifying the processes responsible for switches between, for instance, sexual and asexual reproduction, or cyclic and non-cyclic life histories remains challenging. When animals evolve parthenogenetic reproduction, information about the sexual mating system becomes lost. Here we report an extraordinary...
متن کاملSex Reversal in Amphibians.
Amphibians have been widely used to study developmental biology due to the fact that embryo development takes place independently of the maternal organism and that observations and experimental approaches are easy. Some amphibians like Xenopus became model organisms in this field. In the first part of this article, the differentiation of the gonads in amphibians and the mechanisms governing thi...
متن کاملSex Reversal in Birds.
Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexu...
متن کاملMicromalthus debilis
There are over 360,000 described species of beetles. Why does this one deserve its own Quick Guide? For two reasons. The first is its bizarre life cycle (Figure 1). Most of the year, a population of M. debilis consists entirely of larvae, which reproduce by giving live birth to more larvae. This is a form of parthenogenetic reproduction — all the individuals are females, and no mating occurs. B...
متن کاملmolecular and physiological characterizations of floral scent production in rosa damascena mill.
گل محمدی (r. damascena mill.)مهمترین گونه ای است که در تولید گلاب، عطر و اسانس، در صنعت عطرسازی و دارویی کاربرد دارد. با وجود اهمیت عطر گل محمدی، پژوهش های مولکولی و بیوشیمیایی عطر گل این گونه هنوز در مراحل ابتدایی است. در این پژوهش، ویژگی های مولکولی و فیزیولوژیکی تولید عطر در گل محمدی در آزمایش های مختلف مورد بررسی قرار گرفتند. در آزمایش اول، پژوهشی به منظور بررسی تنوع شیمیایی اسانس میان 44 ت...
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ژورنال
عنوان ژورنال: The Biological Bulletin
سال: 1941
ISSN: 0006-3185,1939-8697
DOI: 10.2307/1537915