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The Sri Lankan junglefowl (Gallus lafayettii sometimes spelled Gallus lafayetii), also known as the Ceylon junglefowl or Lafayette's junglefowl, is a member of the Galliformes bird order which is endemic to Sri Lanka, where it is the national bird.
Junglefowl are the only four living species of bird from the genus Gallus in the bird order Galliformes, and occur in parts of South and Southeast Asia.One of the species in this genus, the red junglefowl, is of historical importance as the direct ancestor of the domestic chicken, although the grey junglefowl, Sri Lankan junglefowl and green junglefowl are likely to have also been involved. [2]
The red junglefowl was the primary species to give rise to today's many breeds of domesticated chicken (G. g. domesticus); additionally, the related grey junglefowl (G. sonneratii), Sri Lankan junglefowl (G. lafayettii) and the Javanese green junglefowl (G. varius) have also contributed genetic material to the gene pool of the modern chicken.
The classification appears to be an early example of cladistic classification [clarification needed] because it codifies many intermediate levels of taxa: the "trunk" of the family tree is the class Aves, which branches into subclasses, which branch into infraclasses, and then "parvclasses", superorders, orders, suborders, infraorders, "parvorders", superfamilies, families, subfamilies, tribes ...
Molecular phylogenetics (/ m ə ˈ l ɛ k j ʊ l ər ˌ f aɪ l oʊ dʒ ə ˈ n ɛ t ɪ k s, m ɒ-, m oʊ-/ [1] [2]) is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships.
Watson and Crick used many aluminium templates like this one, which is the single base Adenine (A), to build a physical model of DNA in 1953. When Watson and Crick produced their double helix model of DNA, it was known that most of the specialized features of the many different life forms on Earth are made possible by proteins.
The DNA model shown (far right) is a space-filling, or CPK, model of the DNA double helix. Animated molecular models, such as the wire, or skeletal, type shown at the top of this article, allow one to visually explore the three-dimensional (3D) structure of DNA. Another type of DNA model is the space-filling, or CPK, model.
The current theoretical model of the atom involves a dense nucleus surrounded by a probabilistic "cloud" of electrons. Atomic theory is the scientific theory that matter is composed of particles called atoms. The definition of the word "atom" has changed over the years in response to scientific discoveries.