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Arvicola Sapidus
The southwestern water vole or southern water vole (''Arvicola sapidus'') is a large amphibious vole native to most of France and southwestwards through Spain and Portugal. It is listed on the IUCN Red List as Vulnerable species, vulnerable. Reproductive cycle The reproductive cycle of the southwestern water vole varies seasonally and geographically, with the most intense reproductive activity occurring from March through October, peaking between April and June. Although reproduction occurs year-round, a distinct reduction in reproductive activity occurs from November through February, coinciding with lower temperatures and shorter day lengths. Females become sexual maturity, sexually mature when they reach a weight of around 140 grams, with larger individuals typically having higher reproductive success. On average, females produce litters of about four offspring (range 1–7). Litter size is directly correlated with maternal body weight, with heavier females tending to have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerrit Smith Miller Jr
Gerrit is a Dutch male name meaning "''brave with the spear''", the Dutch and Frisian form of Gerard. People with this name include: * Gerrit Achterberg (1905–1962), Dutch poet * Gerrit van Arkel (1858–1918), Dutch architect * Gerrit Badenhorst (born 1962), South African powerlifter and professional strongman competitor * Gerrit Battem (c. 1636 – 1684), Dutch landscape painter * Gerrit Beneker (1882–1934), American painter and illustrator * Gerrit Berckheyde (1638–1698), Dutch painter * Gerrit Berkhoff (1901–1996), Dutch chemist and university rector * Gerrit Cornelis Berkouwer (1903–1996), Dutch theologian * Gerrit Berveling (born 1944), Dutch Esperanto author * Gerrit Blaauw (1924–2018), Dutch computer engineer * Gerrit de Blanken (1894–1961), Dutch pottery artist * Gerrit van Bloclant (1578–1650), Dutch Renaissance painter * Gerrit Bol (1906–1989), Dutch mathematician * Gerrit Braamcamp (1699–1771), Dutch distiller, timber merchant and art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testes
A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of androgens, primarily testosterone. The release of testosterone is regulated by luteinizing hormone (LH) from the anterior pituitary gland. Sperm production is controlled by follicle-stimulating hormone (FSH) from the anterior pituitary gland and by testosterone produced within the gonads. Structure Appearance Males have two testicles of similar size contained within the scrotum, which is an extension of the abdominal wall. Scrotal asymmetry, in which one testicle extends farther down into the scrotum than the other, is common. This is because of the differences in the vasculature's anatomy. For 85% of men, the right testis hangs lower than the left one. Measurement and volume The volume of the testicle can be estimated by palpating it and comparing it to ellipsoids (an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refugium (population Biology)
In biology, a refugium (plural: ''refugia'') is a location which supports an isolated or relict population of a once more widespread species. This isolation ( allopatry) can be due to climatic changes, geography, or human activities such as deforestation and overhunting. Present examples of refugial animal species are the mountain gorilla, isolated to specific mountains in central Africa, and the Australian sea lion, isolated to specific breeding beaches along the south-west coast of Australia, due to humans taking so many of their number as game. This resulting isolation, in many cases, can be seen as only a temporary state; however, some refugia may be longstanding, thereby having many endemic species, not found elsewhere, which survive as relict populations. The Indo-Pacific Warm Pool has been proposed to be a longstanding refugium, based on the discovery of the "living fossil" of a marine dinoflagellate called '' Dapsilidinium pastielsii'', currently found only in the ... [...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 or a small set of alleles. Specific contiguous parts of the chromosome are likely to be inherited together and not be split by chromosomal crossover, a phenomenon called genetic linkage. As a result, identifying these statistical associations and a few alleles of a specif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iberia
The Iberian Peninsula ( ), also known as Iberia, is a peninsula in south-western Europe. Mostly separated from the rest of the European landmass by the Pyrenees, it includes the territories of peninsular Spain and Continental Portugal, comprising most of the region, as well as the tiny adjuncts of Andorra, Gibraltar, and, pursuant to the traditional definition of the Pyrenees as the peninsula's northeastern boundary, a small part of France. With an area of approximately , and a population of roughly 53 million, it is the second-largest European peninsula by area, after the Scandinavian Peninsula. Etymology The Iberian Peninsula has always been associated with the River Ebro (Ibēros in ancient Greek and Ibērus or Hibērus in Latin). The association was so well known it was hardly necessary to state; for example, Ibēria was the country "this side of the Ibērus" in Strabo. Pliny goes so far as to assert that the Greeks had called "the whole of the peninsula" Hiberia beca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome B
Cytochrome b is a protein found in the membranes of aerobic cells. In eukaryotic mitochondria (inner membrane) and in aerobic prokaryotes, cytochrome b is a component of respiratory chain complex III () — also known as the bc1 complex or ubiquinol-cytochrome c reductase. In plant chloroplasts and cyanobacteria, there is a homologous protein, cytochrome b6, a component of the plastoquinone-plastocyanin reductase (), also known as the b6f complex. These complexes are involved in electron transport, the pumping of protons to create a proton-motive force ( PMF). This proton gradient is used for the generation of ATP. These complexes play a vital role in cells. Structure and function Cytochrome b/b6 is an integral membrane protein of approximately 400 amino acid residues that probably has 8 transmembrane segments. In plants and cyanobacteria, cytochrome b6 consists of two protein subunits encoded by the petB and petD genes. Cytochrome b/b6 non-covalently binds two heme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeography
Phylogeography is the study of the historical processes that may be responsible for the past to present geographic distributions of genealogical lineages. This is accomplished by considering the geographic distribution of individuals in light of genetics, particularly population genetics. This term was introduced to describe geographically structured genetic signals within and among species. An explicit focus on a species' biogeography/biogeographical past sets phylogeography apart from classical population genetics and phylogenetics. Past events that can be inferred include population expansion, population bottlenecks, vicariance, dispersal, and human migration, migration. Recently developed approaches integrating coalescent theory or the genealogical history of alleles and distributional information can more accurately address the relative roles of these different historical forces in shaping current patterns. Historical development The term phylogeography was first used by Joh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arvicola Amphibius
The European water vole (''Arvicola amphibius'') or northern water vole is a semi-aquatic rodent. It is often informally called the water rat, though it only superficially resembles a true rat. Water voles have rounder noses than rats, deep brown fur, chubby faces and short fuzzy ears; unlike rats their tails, paws and ears are covered with hair. In the wild, on average, water voles only live about five months. Maximum longevity in captivity is two and a half years. Appearance Water voles reach in length, plus a tail which is about half the length of the body. Weights reported for adults are variable. It is possible for large, optimal adults to weigh as much as However, these are peak weights. Elsewhere, the mean body mass has been reported as , although this figure includes immature water voles. The minimum weight to successfully breed as well as to survive winter is reportedly in females and in males.Yavuz, Güliz, Ercüment Çolak, and Teoman Kankılıç. ''Investigat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is distinguished from '' genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long-distance Dispersal
Biological dispersal refers to both the movement of individuals (animals, plants, fungi, bacteria, etc.) from their birth site to their breeding site ('natal dispersal') and the movement from one breeding site to another ('breeding dispersal'). Dispersal is also used to describe the movement of propagules such as seeds and spores. Technically, dispersal is defined as any movement that has the potential to lead to gene flow. The act of dispersal involves three phases: departure, transfer, and settlement. There are different fitness costs and benefits associated with each of these phases. Through simply moving from one habitat patch to another, the dispersal of an individual has consequences not only for individual fitness, but also for population dynamics, population genetics, and species distribution. Understanding dispersal and the consequences, both for evolutionary strategies at a species level and for processes at an ecosystem level, requires understanding on the type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Flow
In population genetics, gene flow (also known as migration and allele flow) is the transfer of genetic variation, genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent allele frequencies and therefore can be considered a single effective population. It has been shown that it takes only "one migrant per generation" to prevent populations from diverging due to Genetic drift, drift. Populations can diverge due to Natural selection, selection even when they are exchanging alleles, if the selection pressure is strong enough. Gene flow is an important mechanism for transferring genetic diversity among populations. Migrants change the distribution of genetic diversity among populations, by modifying allele frequencies (the proportion of members carrying a particular variant of a gene). High rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity. Gene flow has b ... [...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] |
