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Perote Ground Squirrel
The Perote ground squirrel (''Xerospermosphilus perotensis'') is a species of rodent in the family Sciuridae. It is endemic to Mexico and is currently at risk of extinction. Perote ground squirrels live within the same area as rock squirrels ('' Otospermophilus variegatus'') but they use different microhabitats. In one case it also shares its habitat with the Mexican ground squirrel (''Ictidomys mexicanus'').Valdéz, Manuel, Gerardo Ceballos. "Conservation of Endemic Mammals of Mexico: The Perote Ground Squirrel (''Spermophilus perotensis'')." Journal of Mammalogy 78.1 (1997): 74. Perote ground squirrels have traits similar to those of spotted ground squirrels ('' X. spilosoma pallescens'') found in the northern Mexican Plateau; however they are larger, have shorter tails and yellow backs. Its skull is relatively narrow with a large braincase and they have heavy, thick teeth.Fernández, Jesús A. "Phylogenetics and Biogeography of the Microendemic Rodent(Perote Ground Squirrel) in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perote Pocket Gopher
The Perote pocket gopher (''Cratogeomys perotensis''), or Cofre de Perote pocket gopher, is a species of pocket gopher in the family Geomyidae. Range Endemic to Mexico, it is found in the mountains from southern Hildalgo south through Puebla and Veracruz to the volcanic edifices of Cofre de Perote and Pico de Orizaba, the former being the type locality. Description This rodent is light to dark brown in color and weighs 400 to 650 g, with males being slightly larger. There are usually small white areas near the base of the tail. Its karyotype has 2n = 38 and FN = 72. Habitat It inhabits Zacatonal grassland and temperate pine-oak woodlands at elevations from 2400 to 4000 m. Taxonomic history Initially described as a species in 1895, ''C. perotensis'' was demoted to a subspecies of '' C. merriami'' in 1968. In 2005 it was split off again when found to be distinct in molecular, chromosomal and morphological characters. It subsumes the previously proposed taxa ''C. estor'' (Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agricultural Expansion
Agricultural expansion describes the growth of agricultural land (arable land, pastures, etc.) especially in the 20th and 21st centuries. The agricultural expansion is often explained as a direct consequence of the global increase in food and energy requirements due to continuing population growth (both which in turn have been attributed to agricultural expansion itself), with an estimated expectation of 10 to 11 billion humans on Earth by end of this century. It is foreseen that most of the world's non-agrarian ecosystems (terrestrial and aquatic) will be affected adversely, from habitat loss, land degradation, overexploitation, and other problems. The intensified food (and biofuel) production will in particular affect the tropical regions. Most modern agriculture relies on intensive methods. Further expansion of the predominant farming types that rest on a small number of highly productive crops has led to a significant loss of biodiversity on a global scale already. More ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammals Described In 1893
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tehuacán Valley Matorral
The Tehuacán Valley matorral is a xeric shrubland ecoregion, of the deserts and xeric shrublands biome, located in eastern Tehuacan, Central Mexico. Matorral is a Spanish language, Spanish word, along with ''tomillares'', for shrubland, thicket or bushes. The term is used alone for a Mediterranean climate ecosystem in Southern Europe. Geography The Tehuacán Valley matorral ecoregion occupies the Tehuacan Valley, Tehuacán Valley, Oriental Basin, and adjacent valleys, covering parts of the states of Tlaxcala, Puebla and Oaxaca. The valleys lie in the rain shadow of the surrounding mountain ranges, and are drier than the surrounding ecoregions. Adjacent ecoregions The Tehuacán Valley matorral is bounded by the Trans-Mexican Volcanic Belt pine-oak forests to the northwest, north, and northeast, the Sierra Madre de Oaxaca pine-oak forests to the east, and by the Balsas dry forests to the southeast, south, and southwest. Flora The Tehuacán Valley matorral is a center of plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Mammals Of Mexico
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can be also be referred to as an ''endemism'' or in scientific literature as an ''endemite''. For example '' Cytisus aeolicus'' is an endemite of the Italian flora. '' Adzharia renschi'' was once believed to be an endemite of the Caucasus, but it was later discovered to be a non-indigenous species from South America belonging to a different genus. The extreme opposite of an endemic species is one with a cosmopolitan distribution, having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xerospermophilus
Pygmy ground squirrels are small ground squirrels in the genus ''Xerospermophilus'', family Sciuridae, containing four species from Mexico and the United States. The members of this genus were formerly placed in the large ground squirrel genus ''Spermophilus''. Since DNA sequencing of the cytochrome ''b'' gene has shown ''Spermophilus'' to be paraphyletic to the prairie dogs and marmots, this group is now separated, along with six other genera. Within the genus, the Mohave ground squirrel and the round-tailed ground squirrel were thought to be close relatives, sometimes a subgenus ''Xerospermophilus'', while the spotted ground squirrel and the Perote ground squirrel were placed in the subgenus (now a genus) ''Ictidomys''. The name of the genus is a combination of the Greek word ''xeros'', "dry", and ''Spermophilus'', which also comes from Greek, meaning "seed lovers". Species The four species in ''Xerospermophilus'' are listed below. These are the same species that were previ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mustela Frenata
The long-tailed weasel (''Neogale frenata''), also known as the bridled weasel, masked ermine, or big stoat, is a species of mustelid distributed from southern Canada throughout all the United States and Mexico, southward through all of Central America and into northern South America. It is distinct from the short-tailed weasel (''Mustela erminea''), also known as a "stoat", a close relation in the genus '' Mustela'' that originated in Eurasia and crossed into North America some half million years ago; the two species are visually similar, especially the black tail tip. Taxonomy Originally described in the genus '' Mustela'', a 2021 study reclassified it into the genus ''Neogale'' along with 2 other former ''Mustela'' species, as well as the two species formerly classified in ''Neovison''. Evolution The long-tailed weasel is the product of a process begun 5–7 million years ago, when northern forests were replaced by open grassland, thus prompting an explosive evolution of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environmental Change
Environmental change is a change or disturbance of the environment most often caused by human influences and natural ecological processes. Environmental changes include various factors, such as natural disasters, human interferences, or animal interaction. Environmental change encompasses not only physical changes, but also factors like an infestation of invasive species. See also * Climate change (general concept) * Environmental degradation * Global warming * Human impact on the environment * Acclimatization * Atlas of Our Changing Environment * Phenotypic plasticity * Socioeconomics Socioeconomics (also known as social economics) is the social science that studies how economic activity affects and is shaped by social processes. In general it analyzes how modern society, societies social progress, progress, economic stagnation ... References {{Reflist Ecology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinction
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squirrel
Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squirrels are indigenous to the Americas, Eurasia, and Africa, and were introduced by humans to Australia. The earliest known fossilized squirrels date from the Eocene epoch, and among other living rodent families, the squirrels are most closely related to the mountain beaver and to the dormice. Etymology The word ''squirrel'', first attested in 1327, comes from the Anglo-Norman which is from the Old French , the reflex of a Latin word , which was taken from the Ancient Greek word (; from ) 'shadow-tailed', referring to the long bushy tail which many of its members have. The native Old English word for the squirrel, , survived only into Middle English (as ) before being replaced. The Old English word is of Common Germanic origin, cognat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplotype
A haplotype ( haploid genotype) is a group of alleles in an organism that are inherited together from a single parent. Many organisms contain genetic material ( DNA) which is inherited from two parents. Normally these organisms have their DNA organized in two sets of pairwise similar chromosomes. The offspring gets one chromosome in each pair from each parent. A set of pairs of chromosomes is called diploid and a set of only one half of each pair is called haploid. The haploid genotype (haplotype) is a genotype that considers the singular chromosomes rather than the pairs of chromosomes. It can be all the chromosomes from one of the parents or a minor part of a chromosome, for example a sequence of 9000 base pairs. However, there are other uses of this term. First, it is used to mean a collection of specific alleles (that is, specific DNA sequences) in a cluster of tightly linked genes on a chromosome that are likely to be inherited together—that is, they are likely to be con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus and, in plants and algae, also in plastids such as chloroplasts. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that the human mtDNA includes 16,569 base pairs and encodes 13 proteins. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits an examination of the relatedness of populations, and so has become important in anthropology and biogeography. Origin Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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