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Western Palearctic Black-and-white Flycatchers
The term Western Palearctic black-and-white flycatchers is used to refer to a group of similar-looking birds in the genus ''Ficedula'': * Atlas pied flycatcher ''F. speculigera'' which breeds in Northwest Africa * Collared flycatcher ''F. albicollis'' which breeds in Eastern Europe * European pied flycatcher ''F. hypoleuca'' which breeds in Western Europe * Semi-collared flycatcher ''F. semitorquata'' of Southeast Europe and Southwest Asia European pied and collared flycatchers hybridise to a limited extent where their ranges meet; the hybrids have reduced fitness and usually do not survive their first winter (Parkin 2003). Female hybrids are usually sterile (Gelter ''et al.'' 1992; ''see also'' Haldane's Rule). All species leave their breeding grounds to winter in Sub-Saharan Africa. References * Gelter, H. P.; Tegelström, H. & Gustafsson, L. (1992): Evidence from hatching success and DNA fingerprinting for the fertility of hybrid Pied × Collared Flycatchers ''Ficedula hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the bee hummingbird to the ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming. B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semi-collared Flycatcher
The semicollared flycatcher (''Ficedula semitorquata'') is a small passerine bird in the Old World flycatcher family, one of the four species of Western Palearctic black-and-white flycatchers. It breeds in montane forests of the southeastern corner of Europe (Balkan Peninsula) to Northwest Iran. It is migratory, wintering in Central and Eastern Africa. It is a rare vagrant in western Europe. Tracking studies using geolocators have revealed that weather conditions during spring migration can have a large impact on the timing of Semicollared flycatcher migration and survival of adult birds. This is a 12–13.5 cm long bird, intermediate in appearance between collared flycatcher and European pied flycatcher. It has often been classed as a subspecies of collared flycatcher. The breeding male is mainly black above and white below, with a white half-collar, extending further back than in pied, large white wing patch, extensively white tail sides and a large white forehead patch. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sub-Saharan Africa
Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sovereign states and dependent territories in Africa, African countries and territories that are situated fully in that specified region, the term may also include polities that only have part of their territory located in that region, per the definition of the United Nations (UN). This is considered a non-standardized geographical region with the number of countries included varying from 46 to 48 depending on the organization describing the region (e.g. UN, WHO, World Bank, etc.). The Regions of the African Union, African Union uses a different regional breakdown, recognizing all 55 member states on the continent - grouping them into 5 distinct and standard regions. The term serves as a grouping counterpart to North Africa, which is instead ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infertility
Infertility is the inability of a person, animal or plant to reproduce by natural means. It is usually not the natural state of a healthy adult, except notably among certain eusocial species (mostly haplodiploid insects). It is the normal state of a human child or other young offspring, because they have not undergone puberty, which is the body's start of reproductive capacity. In humans, infertility is the inability to become pregnant after one year of unprotected and regular sexual intercourse involving a male and female partner.Chowdhury SH, Cozma AI, Chowdhury JH. Infertility. Essentials for the Canadian Medical Licensing Exam: Review and Prep for MCCQE Part I. 2nd edition. Wolters Kluwer. Hong Kong. 2017. There are many causes of infertility, including some that medical intervention can treat. Estimates from 1997 suggest that worldwide about five percent of all heterosexual couples have an unresolved problem with infertility. Many more couples, however, experience involu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fitness (biology)
Fitness (often denoted w or ω in population genetics models) is the quantitative representation of individual reproductive success. It is also equal to the average contribution to the gene pool of the next generation, made by the same individuals of the specified genotype or phenotype. Fitness can be defined either with respect to a genotype or to a phenotype in a given environment or time. The fitness of a genotype is manifested through its phenotype, which is also affected by the developmental environment. The fitness of a given phenotype can also be different in different selective environments. With asexual reproduction, it is sufficient to assign fitnesses to genotypes. With sexual reproduction, recombination scrambles alleles into different genotypes every generation; in this case, fitness values can be assigned to alleles by averaging over possible genetic backgrounds. Natural selection tends to make alleles with higher fitness more common over time, resulting in Darwin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southwest Asia
Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes Anatolia, the Arabian Peninsula, Iran, Mesopotamia, the Armenian highlands, Armenian Highlands, the Levant, the island of Cyprus, the Sinai Peninsula, and partly the Caucasus, Caucasus Region (Transcaucasia). The region is considered to be separated from Africa by the Isthmus of Suez in Egypt, and separated from Europe by the waterways of the Turkish Straits and the watershed of the Greater Caucasus. Central Asia lies to its northeast, while South Asia lies to its east. Twelve seas surround the region (clockwise): the Aegean Sea, the Sea of Marmara, the Black Sea, the Caspian Sea, the Persian Gulf, the Gulf of Oman, the Arabian Sea, the Gulf of Aden, the Red Sea, the Gulf of Aqaba, the Gulf of Suez, and the Mediterranean Sea. Western Asia cove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southeast Europe
Southeast Europe or Southeastern Europe (SEE) is a geographical subregion of Europe, consisting primarily of the Balkans. Sovereign states and territories that are included in the region are Albania, Bosnia and Herzegovina, Bulgaria, Croatia (alternatively placed in Central Europe), Cyprus (alternatively placed in West Asia), Greece (alternatively placed in Southern Europe), Kosovo, Montenegro, North Macedonia, Romania, Serbia, and Turkey (alternatively placed in Southern Europe or West Asia). Sometimes, Moldova (alternatively placed in Eastern Europe) and Slovenia (alternatively placed in Central Europe) are also included. The largest city of the region is Istanbul, followed by Bucharest, Sofia, Belgrade, and Athens. There are overlapping and conflicting definitions of the region, due to political, economic, historical, cultural, and geographical considerations. Definition The first known use of the term "Southeast Europe" was by Austrian researcher Johann Georg von Hahn (1811â ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean world, the Roman Empire (Western Roman Empire and Eastern Roman Empire), and medieval "Christendom" (Western Christianity and Eastern Christianity). Beginning with the Renaissance and the Age of Discovery, roughly from the 15th century, the concept of ''Europe'' as "the West" slowly became distinguished from and eventually replaced the dominant use of "Christendom" as the preferred endonym within the region. By the Age of Enlightenment and the Industrial Revolution, the concepts of "Eastern Europe" and "Western Europe" were more regularly used. Historical divisions Classical antiquity and medieval origins Prior to the Roman conquest, a large part of Western Europe had adopted the newly developed La Tène culture. As the Roman domain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
European Pied Flycatcher
The European pied flycatcher (''Ficedula hypoleuca'') is a small passerine bird in the Old World flycatcher family. One of the four species of Western Palearctic black-and-white flycatchers, it bird hybrid, hybridizes to a limited extent with the collared flycatcher. It breeds in most of Europe and across the Western Palearctic. It is migratory, wintering mainly in tropical Africa. It usually builds its nests in holes on oak trees. This species practices polygyny, usually bigamy, with the male travelling large distances to acquire a second mate. The male will mate with the secondary female and then return to the primary female in order to help with aspects of child rearing, such as feeding. The European pied flycatcher is mainly insectivorous, although its diet also includes other arthropods. This species commonly feeds on spiders, ants, bees and similar prey. The European pied flycatcher has a very large range and population size and so it is of least concern according to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eastern Europe
Eastern Europe is a subregion of the Europe, European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural, and socio-economic connotations. The vast majority of the region is covered by Russia, which spans roughly 40% of the continent's landmass while accounting for approximately 15% of its total population."The Balkans" , ''Global Perspectives: A Remote Sensing and World Issues Site''. Wheeling Jesuit University/Center for Educational Technologies, 1999–2002. It represents a significant part of Culture of Europe, European culture; the main socio-cultural characteristics of Eastern Europe have historically been defined by the traditions of Slavs and Greeks, as well as by the influence of Eastern Christianity as it developed through t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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