نوع (حياتيات)
نوع (species) جاندارن جي اھڙي گروھه کي چيو ويندو آهي جيڪا ساڳئي خاصيتون رکندا آهن. ھن طبقي جا جاندار (نر ۽ مادي) پنهنجي پاڻ ۾ جنسي ميلاپ ڪري پنهنجي نسل کي وڌائي سگھندا آهن.
ھي ٽيڪسانومي جو سڀ کان ننڍو ٽيڪسون آهي. ساڳئي قسم جون نوع ملي ڪري ھڪ ڪٽنب يا خاندان جوڙينديون آهن. جڏهن ساڳئي قسم جا خاندان ملي جلي رھندا آھن ئ آبادي (habitat) ٺاھيندا آھن.
نوع (species) عام طور تي جاندارن جي سڀ کان وڏي گروهه جي طور تي بيان ڪيو ويندو آهي جنهن ۾ مناسب جنس يا ملن جي قسم جا ٻه فرد، عام طور تي جنسي عمل جي ذريعي اولاد پيدا ڪري سگھن ٿا.[1] اها درجه بندي جي بنيادي اڪائي آهي ۽ هڪ جاندار جو هڪ ٽيڪسونومڪ درجو، انهي سان گڏ جيو تنوع جي هڪ اڪائي آھي. نسلن جي وضاحت ڪرڻ جي ٻين طريقن ۾، انھن جي ڪاريوٽائپ، ڊي اين اي جي ترتيب، مورفولوجي، رويا يا ماحولياتي جڳھون شامل آھن. ان کان علاوه، فوسل جا ماهر (Paleontologists) ڪرونو اسپيسس جي تصور کي استعمال ڪندا آهن ڇو ته فوسل جي پيدائش جي جانچ نه ٿي سگهي. eukaryotes جي مجموعي تعداد لاء سڀ کان تازو سخت تخمينو 8 ۽ 8.7 ملين جي وچ ۾ آهي. انهن مان اٽڪل 14 سيڪڙو 2011 تائين بيان ڪيا ويا هئا. سڀني نسلن (سواءِ وائرسن) کي ٻن حصن جو نالو ڏنو ويو آهي، هڪ "بينوميل". هڪ binomial جو پهريون حصو genus آهي جنهن سان تعلق رکندڙ ذات. ٻئي حصي کي مخصوص نالو يا مخصوص اسم سڏيو ويندو آهي (ٻوٽن جي نالي سان، ڪڏهن ڪڏهن زوولوجيڪل نالي ۾ پڻ). مثال طور، بوا ڪنسٽرڪٽر بوا جينس مان هڪ آهي، جنهن ۾ ڪنسٽرڪٽر ذات جو نالو آهي. جڏهن ته مٿي ڏنل وصفون پهرين نظر ۾ مناسب لڳي سگهن ٿيون، جڏهن وڌيڪ ويجهڙائي سان ڏٺو وڃي ته اهي مشڪلاتي نسلن جي تصورن جي نمائندگي ڪن ٿا. مثال طور، ويجهڙائي سان لاڳاپيل نسلن جي وچ ۾ حدون غير واضح ٿي وڃن ٿيون هائبرڊائيزيشن سان، هڪ قسم جي پيچيدگين ۾ سوين هڪجهڙا خوردبيني نسلن جي پيچيدگي ۾، ۽ هڪ انگن جي نسلن ۾. گڏوگڏ، جاندارن جي وچ ۾ جيڪي صرف غير جنسي طور تي ٻيهر پيدا ڪن ٿا، هڪ پيدائش واري نسل جو تصور ڀڃي ٿو، ۽ هر ڪلون ممڪن طور تي هڪ مائڪرو species آهي. جيتوڻيڪ انهن مان ڪي به مڪمل طور تي اطمينان بخش وصفون نه آهن، ۽ جڏهن ته نسلن جو تصور زندگيءَ جو هڪ مڪمل نمونو نه ٿي سگهي، اهو اڃا تائين سائنسدانن ۽ قدامت پسندن لاءِ ڌرتيءَ تي زندگيءَ جي مطالعي لاءِ هڪ ڪارائتو اوزار آهي، نظرياتي مشڪلاتن کان سواءِ.
Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour, or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million.[2][3][4] About 14% of these had been described by 2011.[4] All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes in zoological nomenclature). For example, Boa constrictor is one of the species of the genus Boa, with constrictor being the species' epithet.
While the definitions given above may seem adequate at first glance, when looked at more closely they represent problematic species concepts. For example, the boundaries between closely related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, and in a ring species. Also, among organisms that reproduce only asexually, the concept of a reproductive species breaks down, and each clone is potentially a microspecies. Although none of these are entirely satisfactory definitions, and while the concept of species may not be a perfect model of life, it is still a useful tool to scientists and conservationists for studying life on Earth, regardless of the theoretical difficulties. If species were fixed and clearly distinct from one another, there would be no problem, but evolutionary processes cause species to change. This obliges taxonomists to decide, for example, when enough change has occurred to declare that a lineage should be divided into multiple chronospecies, or when populations have diverged to have enough distinct character states to be described as cladistic species.
Species and higher taxa were seen from the time of Aristotle until the 18th century as categories that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time. Charles Darwin's 1859 book On the Origin of Species explained how species could arise by natural selection. That understanding was greatly extended in the 20th century through genetics and population ecology. Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures. Genes can sometimes be exchanged between species by horizontal gene transfer; new species can arise rapidly through hybridisation and polyploidy; and species may become extinct for a variety of reasons. Viruses are a special case, driven by a balance of mutation and selection, and can be treated as quasispecies.
حوالا
[سنواريو]- ↑ Zimmer, Carl (19 February 2024). "What Is a Species, Anyway? - Some of the best known species on Earth may not be what they seem.". The New York Times. Archived from the original on 19 February 2024. https://archive.today/20240219140255/https://www.nytimes.com/2024/02/19/science/what-is-a-species.html. Retrieved 19 February 2024.
- ↑ Wilson, Edward O. (2018-03-03). "Opinion: The 8 Million Species We Don't Know". The New York Times. ISSN 0362-4331. https://www.nytimes.com/2018/03/03/opinion/sunday/species-conservation-extinction.html.
- ↑ Borenstein, S. "UN report: Humans accelerating extinction of other species". Associated Press.
- ↑ 4.0 4.1 Mora, Camilo; Tittensor, Derek P.; Adl, Sina; Simpson, Alastair G. B.; Worm, Boris (2011-08-23). "How Many Species Are There on Earth and in the Ocean?". PLOS Biology 9 (8): e1001127. doi:. PMID 21886479.