|
Two-toed Sloth
''Choloepus'' is a genus of xenarthran mammals from Central and South America within the monotypic family Choloepodidae, consisting of two-toed sloths, sometimes also called two-fingered sloths. The two species of ''Choloepus'' (which means "lame foot" in Ancient Greek), Linnaeus's two-toed sloth (''Choloepus didactylus'') and Hoffmann's two-toed sloth (''Choloepus hoffmanni''), were formerly believed on the basis of morphological studies to be the only surviving members of the sloth family Megalonychidae, but have now been shown by molecular results to be closest to extinct ground sloths of the family Mylodontidae. Extant species Evolution A study of retrovirus and mitochondrial DNA suggests that ''C. didactylus'' and ''C. hoffmani'' diverged 6 to 7 million years ago. Furthermore, based on cytochrome c oxidase subunit I sequences, a similar divergence date ( years ago) between the two populations of ''C. hofmanni'' separated by the Andes has been reported. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoffmann's Two-toed Sloth
The Hoffmann's two-toed sloth (''Choloepus hoffmanni''), also known as the northern two-toed sloth, is a species of sloth from Central and South America. It is a solitary, largely nocturnal and arboreal animal, found in mature and secondary rainforests and deciduous forests. The common name commemorates the German naturalist Karl Hoffmann, who discovered the Hoffmann sloth. Description Hoffmann's two-toed sloth is a heavily built animal with shaggy fur and slow, deliberate movements. The fore feet have only two toes, each ending with long, curved claws, although three clawed toes are on each of the hind feet. Other features that distinguish it from three-toed sloths, which may be found in the same geographic areas, include the longer snout, separate rather than partially fused toes of the forefeet, the absence of hair on the soles of the feet, fewer dark markings around the eyes, and larger overall size. The wrist of the sloth has developed some specific traits due to their ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mylodontidae
Mylodontidae is a family of extinct South American and North American ground sloths within the suborder Folivora of order Pilosa, living from around 23 million years ago (Mya) to 11,000 years ago. This family is most closely related to another family of extinct ground sloths, Scelidotheriidae, as well as to the extant arboreal two-toed sloths, family Choloepus, Choloepodidae; together these make up the superfamily Mylodontoidea. Phylogenetic analyses based on morphology uncovered the relationship between Mylodontidae and Scelidotheriidae; in fact, the latter was for a time considered a subfamily of mylodontids. However, molecular sequence comparisons were needed for the correct placement of Choloepodidae. These studies have been carried out using mitochondrial DNA sequences as well as with collagen amino acid sequences. The latter results indicate that Choloepodidae is closer to Mylodontidae than Scelidotheriidae is. The only other living sloth family, Bradypodidae (three-toed slot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical data and observed heritable traits of DNA sequences, protein amino acid sequences, and morphology. The results are a phylogenetic tree—a diagram depicting the hypothetical relationships among the organisms, reflecting their inferred evolutionary history. The tips of a phylogenetic tree represent the observed entities, which can be living taxa or fossils. A phylogenetic diagram can be rooted or unrooted. A rooted tree diagram indicates the hypothetical common ancestor of the taxa represented on the tree. An unrooted tree diagram (a network) makes no assumption about directionality of character state transformation, and does not show the origin or "root" of the taxa in question. In addition to their use for inferring phylogenetic pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-toed Sloth
The three-toed or three-fingered sloths are arboreal neotropical mammals. They are the only members of the genus ''Bradypus'' (meaning "slow-footed") and the family Bradypodidae. The five living species of three-toed sloths are the brown-throated sloth, the maned sloth, the pale-throated sloth, the southern maned sloth, and the pygmy three-toed sloth. In complete contrast to past morphological studies, which tended to place ''Bradypus'' as the sister group to all other folivorans, molecular studies place them nested within the sloth superfamily Megatherioidea, making them the only surviving members of that radiation. Extant species Evolution A study of mitochondrial cytochrome b and 16S rRNA sequences suggests that '' B. torquatus'' diverged from '' B. variegatus'' and '' B. tridactylus'' about 12 million years ago, while the latter two split 5 to 6 million years ago. The diversification of ''B. variegatus'' lineages was estimated to have started 4 to 5 million years a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andes
The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18th parallel south, 18°S and 20th parallel south, 20°S latitude) and has an average height of about . The Andes extend from south to north through seven South American countries: Argentina, Chile, Bolivia, Peru, Ecuador, Colombia, and Venezuela. Along their length, the Andes are split into several ranges, separated by intermediate depression (geology), depressions. The Andes are the location of several high plateaus—some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Bucaramanga, Sucre, Mérida, Mérida, Mérida, El Alto, and La Paz. The Altiplano, Altiplano Plateau is the world's second highest after the Tibetan Plateau. These ranges are in turn grouped into three majo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome C Oxidase Subunit I
Cytochrome c oxidase I (COX1) also known as mitochondrially encoded cytochrome c oxidase I (MT-CO1) is a protein that is encoded by the ''MT-CO1'' gene in eukaryotes. The gene is also called ''COX1'', ''CO1'', or ''COI''. Cytochrome c oxidase I is the main subunit of the cytochrome c oxidase complex. In humans, mutations in MT-CO1 have been associated with Leber's hereditary optic neuropathy (LHON), acquired Idiopathic disease, idiopathic sideroblastic anemia, Cytochrome c oxidase, Complex IV deficiency, colorectal cancer, sensorineural deafness, and recurrent myoglobinuria. Structure In humans, the MT-CO1 gene is located from nucleotide pairs 5904 to 7444 on the guanine-rich heavy (H) section of Mitochondrial DNA, mtDNA. The gene product is a 57 kDa protein composed of 513 amino acids. Function Cytochrome c oxidase subunit I (CO1 or MT-CO1) is one of three mitochondrial DNA (mtDNA) encoded subunits (MT-CO1, MT-CO2, MT-CO3) of cytochrome c oxidase, also known as Electron t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in a eukaryotic cell; most of the DNA is in the cell nucleus, and, in plants and algae, the DNA also is found in plastids, such as chloroplasts. Mitochondrial DNA is responsible for coding of 13 essential subunits of the complex oxidative phosphorylation (OXPHOS) system which has a role in cellular energy conversion. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that human mtDNA has 16,569 base pairs and encodes 13 proteins. As in other vertebrates, the human mitochondrial genetic code differs slightly from nuclear DNA. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retrovirus
A retrovirus is a type of virus that inserts a DNA copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell. After invading a host cell's cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus ''retro'' (backward). The new DNA is then retroviral integration, incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell's own genes, producing the proteins required to assemble new copies of the virus. Many retroviruses cause serious diseases in humans, other mammals, and birds. Retroviruses have many subfamilies in three basic groups. * Oncovirus, Oncoretroviruses (cancer-causing retroviruses) include human T-lymphotropic virus (HTLV) causing a type of leuk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Einar Lönnberg
Axel Johann Einar Lönnberg (24 December 1865 – 21 November 1942) was a Swedish zoologist and conservationist. Lönnberg was born in Stockholm. He was head of the Vertebrate Department of the '' Naturhistoriska Riksmuseet'' (Swedish Natural History Museum) from 1904 to 1933. In 1891 he obtained his PhD from the University of Uppsala, spending the next twelve years as an inspector in the fisheries service. During this time-frame he made scientific trips to Florida (1892 – 1893) and the Caspian Sea (1899). In 1904 he was appointed head of the department of vertebrates at the ''Naturhistoriska Riksmuseet'' in Stockholm. In 1910 – 1911 he participated in an expedition to East Africa. From 1925 to 1942 he served as prefect of the ''Kristineberg Marina Forskningsstation'' (Kristineberg Marine Zoological Station). In regard to his zoological research, his primary focus dealt with mammals, birds and fish, but he also made significant contributions in his studies of reptiles a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colombia
Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuela to the east and northeast, Brazil to the southeast, Peru and Ecuador to the south and southwest, the Pacific Ocean to the west, and Panama to the northwest. Colombia is divided into 32 Departments of Colombia, departments. The Capital District of Bogotá is also the List of cities in Colombia by population, country's largest city hosting the main financial and cultural hub. Other major urban areas include Medellín, Cali, Barranquilla, Cartagena, Colombia, Cartagena, Santa Marta, Cúcuta, Ibagué, Villavicencio and Bucaramanga. It covers an area of 1,141,748 square kilometers (440,831 sq mi) and has a population of around 52 million. Its rich cultural heritage—including language, religion, cuisine, and art—reflects its history as a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joel Asaph Allen
Joel Asaph Allen (July 19, 1838 – August 29, 1921) was an American zoology, zoologist, mammalogy, mammalogist, and ornithology, ornithologist. He became the first president of the American Ornithologists' Union, the first curator of birds and mammals at the American Museum of Natural History, and the first head of that museum's Department of Ornithology. He is remembered for Allen's rule, which states that the bodies of endotherms (warm-blooded animals) vary in shape with climate, having increased surface area in hot climates to lose heat, and minimized surface area in cold climates, to conserve heat. Early life Allen was born in Springfield, Massachusetts, the son of Joel Allen and Harriet Trumbull. He studied and collected specimen of natural history early in life, but he was forced to sell his relatively large collection so that he could attend the Wilbraham & Monson Academy in 1861. The following year, he transferred to Harvard University, where he studied under Louis Agassi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panama
Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and the Pacific Ocean to the south. Its capital and largest city is Panama City, whose metropolitan area is home to nearly half of the country's over million inhabitants. Before the arrival of Spanish Empire, Spanish colonists in the 16th century, Panama was inhabited by a number of different Indigenous peoples of Panama, indigenous tribes. It Independence Act of Panama, broke away from Spain in 1821 and joined the Republic of Gran Colombia, a union of Viceroyalty of New Granada, Nueva Granada, Ecuador, and Venezuela. After Gran Colombia dissolved in 1831, Panama and Nueva Granada eventually became the Republic of Colombia. With the backing of the United States, Panama seceded from Colombia in 1903, allowing the construction of the Panama Ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
