|
Dwarf Manatee
The dwarf manatee (''Trichechus pygmaeus'', or mistakenly ''Trichechus bernhardi'') is a disputed species of manatee allegedly found in the freshwater habitats of the Amazon, though restricted to one tributary of the Aripuanã River. According to Marc van Roosmalen, the scientist who proposed it as a new species, it lives in shallow, fast-running water, and feeds on different species of aquatic plants from the Amazonian manatee, which prefers deeper, slower-moving waters and the plants found there. The dwarf manatee reportedly migrates upriver during the rainy season when the river floods to the headwaters and shallow ponds. Based on its small range, the dwarf manatee is suggested to be considered critically endangered if indeed a separate species, but is not recognized by the IUCN.International Union for Conservation of Nature (2008). IUCN Red List'' Accessed November 09, 2009. The dwarf manatee is described as typically being about long and weighing about , which would make i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marc Van Roosmalen
Marc van Roosmalen (born 23 June 1947) is a Dutch-Brazilian primatologist. He was elected as one of the "Heroes for the Planet" by ''Time'' magazine in 2000. His research has led to the identification of several new monkey species, as well as other mammals and plants, although some of these identifications are challenged. He is also an activist in the protection of the Brazilian rainforest. Van Roosmalen was awarded the honour of officer in the Order of the Golden Ark by Prince Bernhard of the Netherlands in 1997. Career Van Roosmalen studied biology at the University of Amsterdam and did four years of doctoral fieldwork beginning in 1976 studying the red-faced spider monkey in Suriname. He later did two more years of work in French Guiana, following which he published the book ''Fruits of the Guianan Flora''. In 1986 he was hired by the INPA (Brazilian National Institute of Amazonian Research, where he initially thrived. During this period, he launched a non-governmental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mutation Rate
In genetics, the mutation rate is the frequency of new mutations in a single gene, nucleotide sequence, or organism over time. Mutation rates are not constant and are not limited to a single type of mutation; there are many different types of mutations. Mutation rates are given for specific classes of mutations. Point mutations are a class of mutations that are changes to a single base. Missense, nonsense, and synonymous mutations are three subtypes of point mutations. The rate of these types of substitutions can be further subdivided into a mutation spectrum, which describes the influence of the genetic context on the mutation rate. There are several natural units of time for each of these rates, with rates being characterized either as mutations per base pair per cell division, per gene per generation, or genome per generation. The mutation rate of an organism is an evolved characteristic and is strongly influenced by the genetics of each organism, in addition to a strong in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controversial Mammal Taxa
Controversy (, ) is a state of prolonged public dispute or debate, usually concerning a matter of conflicting opinion or point of view. The word was coined from the Latin ''controversia'', as a composite of ''controversus'' – "turned in an opposite direction", and also means an exercise in rhetoric practiced in Rome. Legal In the theory of law, a controversy differs from a legal case; while legal cases include all suits, criminal as well as civil, a controversy is a purely civil proceeding. For example, the Case or Controversy Clause of Article Three of the United States Constitution ( Section 2, Clause 1) states that "the judicial Power shall extend ... to Controversies to which the United States shall be a Party". This clause has been deemed to impose a requirement that United States federal courts are not permitted to cases that do not pose an actual controversy—that is, an actual dispute between adverse parties which is capable of being resolved by the our ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manatees
Manatees (, family Trichechidae, genus ''Trichechus'') are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living species in the order Sirenia: the Amazonian manatee (''Trichechus inunguis''), the West Indian manatee (''Trichechus manatus''), and the West African manatee (''Trichechus senegalensis''). They measure up to long, weigh as much as , and have paddle-like tails. Manatees are herbivores and eat over 60 different freshwater and saltwater plants. Manatees inhabit the shallow, marshy coastal areas and rivers of the Caribbean Sea, the Gulf of Mexico, the Amazon basin, and West Africa. The main causes of death for manatees are human-related issues, such as habitat destruction and human objects. Their slow-moving, curious nature has led to violent collisions with propeller-driven boats and ships. Some manatees have been found with over 50 scars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biodiversity Journal
Biodiversity is the variability of life on Earth. It can be measured on various levels. There is for example genetic variability, species diversity, ecosystem diversity and phylogenetic diversity. Diversity is not distributed evenly on Earth. It is greater in the tropics as a result of the warm climate and high primary productivity in the region near the equator. Tropical forest ecosystems cover less than one-fifth of Earth's terrestrial area and contain about 50% of the world's species. There are latitudinal gradients in species diversity for both marine and terrestrial taxa. Since life began on Earth, six major mass extinctions and several minor events have led to large and sudden drops in biodiversity. The Phanerozoic aeon (the last 540 million years) marked a rapid growth in biodiversity via the Cambrian explosion. In this period, the majority of multicellular phyla first appeared. The next 400 million years included repeated, massive biodiversity losses. Thos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smithsonian Magazine
''Smithsonian'' is a magazine covering science, history, art, popular culture and innovation. The first issue was published in 1970. History The history of ''Smithsonian'' began when Edward K. Thompson, the retired editor of ''Life'' magazine, was asked by then-Secretary of the Smithsonian, S. Dillon Ripley, to produce a magazine "about things in which the Smithsonian nstitutionis interested, might be interested or ought to be interested." Thompson later recalled that his philosophy for the new magazine was that it "would stir curiosity in already receptive minds. It would deal with history as it is relevant to the present. It would present art, since true art is never dated, in the richest possible reproduction. It would peer into the future via coverage of social progress and of science and technology. Technical matters would be digested and made intelligible by skilled writers who would stimulate readers to reach upward while not turning them off with jargon. We would fin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution Of Sirenians
Sirenia is the order (biology), order of Eutheria, placental mammals which comprises modern "sea cows" (manatees and the Dugong) and their extinct relatives. They are the only extant herbivorous marine mammals and the only group of herbivorous mammals to have become completely aquatic. Sirenians are thought to have a 50-million-year-old fossil record (early Eocene-recent). They attained modest diversity during the Oligocene and Miocene, but have since declined as a result of climatic cooling, oceanographic changes, and human interference. Two genera and four species are extant: ''Trichechus'', which includes the three species of manatee that live along the Atlantic Ocean, Atlantic coasts and in rivers and coastlines of the Americas and western Africa, and ''Dugong'', which is found in the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Origins Sirenians, along with Proboscidea (elephants), group together with the extinct Desmostylia and likely the extinct Embritho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smithsonian Institution
The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums, Education center, education and Research institute, research centers, created by the Federal government of the United States, U.S. government "for the increase and diffusion of knowledge". Founded on August 10, 1846, it operates as a trust instrumentality and is not formally a part of any of the Federal government of the United States#branches, three branches of the federal government. The institution is named after its founding donor, British scientist James Smithson. It was originally organized as the United States National Museum, but that name ceased to exist administratively in 1967. The Smithsonian Institution has historical holdings of over 157 million items, 21 museums, 21 libraries, 14 education and research centers, a zoo, and historical and architectural landmarks, mostly located in Washington, D.C. Additional facilities are located in Maryland, New York (state), New York, and Virg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Divergence
Genetic divergence is the process in which two or more populations of an ancestral species accumulate independent genetic changes ( mutations) through time, often leading to reproductive isolation and continued mutation even after the populations have become reproductively isolated for some period of time, as there is not any genetic exchange anymore. In some cases, subpopulations cover living in ecologically distinct peripheral environments can exhibit genetic divergence from the remainder of a population, especially where the range of a population is very large (see parapatric speciation). The genetic differences among divergent populations can involve silent mutations (that have no effect on the phenotype) or give rise to significant morphological and/or physiological changes. Genetic divergence will always accompany reproductive isolation, either due to novel adaptations via selection and/or due to genetic drift, and is the principal mechanism underlying speciation. On a m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MtDNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the 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 also permits tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manatee
Manatees (, family (biology), family Trichechidae, genus ''Trichechus'') are large, fully aquatic, mostly herbivory, herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living species in the order Sirenia: the Amazonian manatee (''Trichechus inunguis''), the West Indian manatee (''Trichechus manatus''), and the West African manatee (''Trichechus senegalensis''). They measure up to long, weigh as much as , and have paddle-like tails. Manatees are Herbivory, herbivores and eat over 60 different freshwater and saltwater plants. Manatees inhabit the shallow, marshy coastal areas and rivers of the Caribbean Sea, the Gulf of Mexico, the Amazon basin, and West Africa. The main causes of death for manatees are human-related issues, such as habitat destruction and human objects. Their slow-moving, curious nature has led to violent collisions with propeller-driven boats and ships. Some manatees h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
