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Galea (genus)
''Galea'' is a genus of South American rodents of the family Caviidae. Five extant species are known, found in Argentina, Bolivia, Chile, Peru and Brazil. They are: * Southern highland yellow-toothed cavy ('' G. comes'') * Brazilian yellow-toothed cavy (''G. flavidens'') * Lowland yellow-toothed cavy ('' G. leucoblephara'') * Common yellow-toothed cavy (''G. musteloides'') ** Muenster yellow-toothed cavy (''G. m. monasteriensis'') * Spix's yellow-toothed cavy (''G. spixii'') ''Galea'' has until recently been considered to have only three species; the Muenster yellow-toothed cavy was only described in 2004. ''G. flavidens'' is monotypic and ''G. musteloides'' and ''G. spixii'' are polytypic. ''Galea'' is in the family Caviidae and its members are described as cavies; they have sometimes also been called "guinea pigs". Cavies are widespread throughout South America. The high diversity of habitats of different species is paralleled by a high diversity of social organizations. Spec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene
The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene has been identified with the current warm period, known as MIS 1. It is considered by some to be an interglacial period within the Pleistocene Epoch, called the Flandrian interglacial.Oxford University Press – Why Geography Matters: More Than Ever (book) – "Holocene Humanity" section https://books.google.com/books?id=7P0_sWIcBNsC The Holocene corresponds with the rapid proliferation, growth and impacts of the human species worldwide, including all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. IUCN does not itself aim to mobilize the public in support of nature conservation. It tries to influence the actions of governments, business and other stakeholders by providing information and advice and through building partnerships. The organization is best known to the wider ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Promiscuous
Promiscuity is the practice of engaging in sexual activity frequently with different Sexual partner, partners or being indiscriminate in the choice of sexual partners. The term can carry a moral judgment. A common example of behavior viewed as promiscuous by many cultures is the one-night stand, and its frequency is used by researchers as a marker for promiscuity. What sexual behavior is considered promiscuous varies between cultures, as does the prevalence of promiscuity. Different standards are often applied to different genders and civil statutes. Feminism, Feminists have traditionally argued a significant double standard exists between how men and women are judged for promiscuity. Historically, stereotypes of the promiscuous woman have tended to be pejorative, such as "the slut" or "the harlot", while male stereotypes have been more varied, some expressing approval, such as "the stud" or "the player", while others imply societal deviance, such as "the womanizer" or "the philand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rouleaux
Rouleaux (singular is rouleau) are stacks or aggregations of red blood cells (RBCs) that form because of the unique discoid shape of the cells in vertebrates. The flat surface of the discoid RBCs gives them a large surface area to make contact with and stick to each other; thus forming a rouleau. They occur when the plasma protein concentration is high, and, because of them, the ESR (erythrocyte sedimentation rate) is also increased. This is a nonspecific indicator of the presence of disease.Oxford Textbook of Medicine Conversely, the presence of rouleaux is a cause of disease because it will restrict the flow of blood throughout the body because capillaries can only accept free-flowing singular and independent red blood cells. The aggregations, also known as "clumping," form as an allergic reaction to certain antibiotics and not necessarily because of disease. Conditions that cause rouleaux formation include infections, multiple myeloma, Waldenström's macroglobulinemia, infla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatozoa
A spermatozoon (; also spelled spermatozoön; ; ) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) Sperm cells contribute approximately half of the nuclear genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing an X chromosome will lead to a female (XX) offspring, while one bearing a Y chromosome will lead to a male (XY) offspring. Sperm cells were first observed in Antonie van Leeuwenhoek's laboratory in 1677. Mammalian spermatozoon structure, function, and size Humans The human sperm cell is the reproductive cell in males and will only survive in warm environments; once it leaves the male body the sperm's survival likelihood is reduced and it may die, thereby ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrosome
The acrosome is an organelle that develops over the anterior (front) half of the head in the spermatozoa (sperm cells) of many animals including humans. It is a cap-like structure derived from the Golgi apparatus. In placental mammals the acrosome contains degradative enzymes (including hyaluronidase and acrosin). These enzymes break down the outer membrane of the ovum, called the zona pellucida, allowing the haploid nucleus in the sperm cell to join with the haploid nucleus in the ovum. This shedding of the acrosome, or acrosome reaction, can be stimulated ''in vitro'' by substances a sperm cell may encounter naturally such as progesterone or follicular fluid, as well as the more commonly used calcium ionophore A23187. This can be done to serve as a positive control when assessing the acrosome reaction of a sperm sample by flow cytometry or fluorescence microscopy. This is usually done after staining with a fluoresceinated lectin such as FITC-PNA, FITC-PSA, FITC-ConA, or flu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavia
''Cavia'' is a genus in the subfamily Caviinae that contains the rodents commonly known as guinea pigs or cavies. The best-known species in this genus is the domestic guinea pig, ''Cavia porcellus'', a meat animal in South America and a common household pet outside of that continent. Former taxonomic controversy ''Cavia'' is classified in order Rodentia, although there was once a minority belief in the scientific community that evidence from mitochondrial DNA and proteins suggested the Hystricognathi might belong to a different evolutionary offshoot, and therefore a different order. If this had been so, it would have been an example of convergent evolution. However, this uncertainty is largely of historical interest, as abundant molecular genetic evidence now conclusively supports classification of ''Cavia'' as rodents. This evidence includes draft genome sequences of ''Cavia porcellus'' and several other rodents. Species Historically, there has been little consensus in regard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epididymis
The epididymis (; plural: epididymides or ) is a tube that connects a testicle to a vas deferens in the male reproductive system. It is a single, narrow, tightly-coiled tube in adult humans, in length. It serves as an interconnection between the multiple efferent ducts at the rear of a testicle (proximally), and the vas deferens (distally). Anatomy The epididymis is situated posterior and somewhat lateral to the testis. The epididymis is invested completely by the tunica vaginalis (which is continuous with the tunica vaginalis covering the testis). The epididymis can be divided into three main regions: * The head ( la, caput). The head of the epididymis receives spermatozoa via the efferent ducts of the mediastinium of the testis at the superior pole of the testis. The head is characterized histologically by a thick epithelium with long stereocilia (described below) and a little smooth muscle. It is involved in absorbing fluid to make the sperm more concentrated. The concentrat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Testes
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testosterone. Testosterone release is controlled by the anterior pituitary luteinizing hormone, whereas sperm production is controlled both by the anterior pituitary follicle-stimulating hormone and gonadal testosterone. 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 of known sizes. Another method is to use cali ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guinea Pig
The guinea pig or domestic guinea pig (''Cavia porcellus''), also known as the cavy or domestic cavy (), is a species of rodent belonging to the genus ''Cavia'' in the family Caviidae. Breeders tend to use the word ''cavy'' to describe the animal, while in scientific and laboratory contexts, it is far more commonly referred to by the common name ''guinea pig''. Despite their common name, guinea pigs are not native to Guinea, nor are they closely related biologically to pigs, and the origin of the name is still unclear. They originated in the Andes of South America. Studies based on biochemistry and hybridization suggest they are domesticated animals that do not exist naturally in the wild, descendants of a closely related cavy species such as '' C. tschudii''. They were originally domesticated as livestock for a source of meat, and are still consumed in some parts of the world. In Western society, the guinea pig has enjoyed widespread popularity as a pet since its introducti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spix's Yellow-toothed Cavy
Spix's yellow-toothed cavy (''Galea spixii'') is a rodent, a cavy species from South America. It is found in Bolivia east of the Andes and much of south central to northeastern Brazil. The species is found in open savanna and semiarid habitats, such as the Cerrado and Caatinga of Brazil. Its karyotype A karyotype is the general appearance of the complete set of metaphase chromosomes in the cells of a species or in an individual organism, mainly including their sizes, numbers, and shapes. Karyotyping is the process by which a karyotype is disce ... is 2n = 64 and FN = 118. ''Galea spixii'' and ''G. musteloides'' are similar and may actually be the same species. ''G. spixii'' tolerates a wide range of environmental changes, though they need open habitats. It is the most stable species within the ''Galea'' group because it is extremely abundant throughout its range. Gestation is about fifty days. Litter size ranges from one to five, with an average of three. They have hair and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muenster Yellow-toothed Cavy
The Muenster yellow-toothed cavy (''Galea monasteriensis'') is a species of rodent in the family Caviidae. It is known only from one location in Valle Hermoso in the Bolivian Andes, at an elevation of 2557 m. Specimens from this location were shipped to Muenster Muenster may refer to: * Münster, Germany * Muenster, Saskatchewan * Muenster, Texas * Muenster cheese Muenster ( or ) or munster is a semi-soft cheese from the United States. It is thought to be an imitation of the Alsatian washed-rind Muns ..., Germany in 1997 for laboratory research, where the species was recognized and described. ''Galea monasteriensis'' was recognized on the basis of morphological, behavioral, and reproductive differences from related species. However, its habits in the wild have not been studied. Since 2016, the IUCN has regarded this population as a subspecies of the common yellow-toothed cavy, i.e. as ''Galea musteloides'' ssp. ''monasteriensis''. Unlike the :common yellow-toothed ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
