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Nettie Maria Stevens
Nettie Maria Stevens (July 7, 1861 – May 4, 1912) was an American geneticist who discovered sex chromosomes. In 1905, soon after the rediscovery of Mendel's paper on genetics in 1900, she observed that male mealworms produced two kinds of sperm, one with a large chromosome and one with a small chromosome. When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. The pair of sex chromosomes that she studied later became known as the X and Y chromosomes. Early life Nettie Maria Stevens was born on July 7, 1861, in Cavendish, Vermont, to Julia (née Adams) and Ephraim Stevens. In 1863, after the death of her mother, her father remarried and the family moved to Westford, Massachusetts.MB Ogilvie, CJ Choquette (1981) "Nettie Maria Stevens (1861–1912): her life and contributions to cytogenetics. ''Proc Amer Phil Soc US'' 125(4):292–311. Her father worked a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavendish, Vermont
Cavendish is a town in Windsor County, Vermont, United States. The town was likely named after William Cavendish, 4th Duke of Devonshire. The population was 1,392 at the 2020 census. The town of Cavendish includes the unincorporated villages of Cavendish and Proctorsville. History Early settlers Captain John Coffeen, the town's first permanent settler, brought his family and possessions into the wilderness of Cavendish in June 1769. They built a dwelling in the northern part of town on what is now E. I. Heald's farm, on the lot still called the "Coffeen pasture". The Coffeens remained the only family in Cavendish for two years. In the early 1780s, Leonard Proctor and Salmon Dutton came from Massachusetts and gave their names to the two major settlements on the Black River, Proctorsville and Duttonsville. In 1782, the first recorded town meeting occurred and Dutton was elected town clerk. He is credited with having conducted a 1784 survey for the first road from Duttonsville alo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physiology
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical and physical functions in a living system. According to the classes of organisms, the field can be divided into medical physiology, animal physiology, plant physiology, cell physiology, and comparative physiology. Central to physiological functioning are biophysical and biochemical processes, homeostatic control mechanisms, and communication between cells. ''Physiological state'' is the condition of normal function. In contrast, ''pathological state'' refers to abnormal conditions, including human diseases. The Nobel Prize in Physiology or Medicine is awarded by the Royal Swedish Academy of Sciences for exceptional scientific achievements in physiology related to the field of medicine. Foundations Cells Although there are differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Trait inheritance and molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded to study the function and behavior of genes. Gene structure and function, variation, and distribution are studied within the context of the cell, the organism (e.g. dominance), and within the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nettie Stevens Microscope (2)
Nettie may refer to: Literature *The Nettie Palmer Prize for Non-fiction, an Australian literary award offered for a published work of non-fiction and a component of the annual Victorian Premier's Literary Award Medicine * Nettie pot, also neti pot, a device used for nasal irrigation Music *"Nettie", a song by Type O Negative's on the album ''Life Is Killing Me'' *"Nettie Moore", a song on the album ''Modern Times'' (Bob Dylan album) People *Nettie (name) Places *Nettie, West Virginia, an unincorporated community in Nicholas County, West Virginia, in the United States *Lake Nettie National Wildlife Refuge in North Dakota in the United States Ships * USS ''Nettie'' (SP-1436), a United States Navy patrol boat in commission from 1917 to 1918 See also *Neti (other) *Netti (other) *Netty (other) Netty may refer to: * Netty (software), a Java project * North East England (Geordie) dialect for toilet or public convenience *Netty (name) See also * We ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Association Of University Women
The American Association of University Women (AAUW), officially founded in 1881, is a non-profit organization that advances equity for women and girls through advocacy, education, and research. The organization has a nationwide network of 170,000 members and supporters, 1,000 local branches, and 800 college and university partners. Its headquarters are in Washington, D.C. AAUW's CEO is Gloria L. Blackwell. History 19th century In 1881, Marion Talbot and Ellen Swallow Richards invited 15 alumnae from 8 colleges to a meeting in Boston, Massachusetts. The purpose of this meeting was to create an organization of women college graduates that would assist women in finding greater opportunities to use their education, as well as promoting and assisting other women's college attendance. The Association of Collegiate Alumnae or ACA, (AAUW's predecessor organization) was officially founded on January 14, 1882. The ACA also worked to improve standards of education for women so that men and wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spermatogenesis
Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubules. These cells are called spermatogonial stem cells. The mitotic division of these produces two types of cells. Type A cells replenish the stem cells, and type B cells differentiate into primary spermatocytes. The primary spermatocyte divides meiotically (Meiosis I) into two secondary spermatocytes; each secondary spermatocyte divides into two equal haploid spermatids by Meiosis II. The spermatids are transformed into spermatozoa (sperm) by the process of spermiogenesis. These develop into mature spermatozoa, also known as sperm cells. Thus, the primary spermatocyte gives rise to two cells, the secondary spermatocytes, and the two secondary spermatocytes by their subdivision produce four spermatozoa and four haploid cells. Spermatozoa are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex-determination System
A sex-determination system is a biological system that determines the development of sexual characteristics in an organism. Most organisms that create their offspring using sexual reproduction have two sexes. In some species there are hermaphrodites. There are also some species that are only one sex due to parthenogenesis, the act of a female reproducing without fertilization. In some species, sex determination is genetic: males and females have different alleles or even different genes that specify their sexual morphology. In animals this is often accompanied by chromosomal differences, generally through combinations of XY, ZW, XO, ZO chromosomes, or haplodiploidy. The sexual differentiation is generally triggered by a main gene (a "sex locus"), with a multitude of other genes following in a domino effect. In other cases, sex of a fetus is determined by environmental variables (such as temperature). The details of some sex-determination systems are not yet fully underst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mendelian Inheritance
Mendelian inheritance (also known as Mendelism) is a type of biological inheritance following the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 by Hugo de Vries and Carl Correns, and later popularized by William Bateson. These principles were initially controversial. When Mendel's theories were integrated with the Boveri–Sutton chromosome theory of inheritance by Thomas Hunt Morgan in 1915, they became the core of classical genetics. Ronald Fisher combined these ideas with the theory of natural selection in his 1930 book ''The Genetical Theory of Natural Selection'', putting evolution onto a mathematical footing and forming the basis for population genetics within the modern evolutionary synthesis. History The principles of Mendelian inheritance were named for and first derived by Gregor Johann Mendel, a nineteenth-century Moravian monk who formulated his ideas after conducting simple hybridisation experiments with pea plants (' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnegie Institution For Science
The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. The institution is headquartered in Washington, D.C. , the Institution's endowment was valued at $926.9 million. In 2018 the expenses for scientific programs and administration were $96.6 million. Eric Isaacs is president of the institution. Name More than 20 independent organizations were established through the philanthropy of Andrew Carnegie and now feature his surname. They perform work involving topics as diverse as art, education, international affairs, world peace, and scientific research. In 2007, the Carnegie Institution of Washington adopted the public name "Carnegie Institution for Science" to distinguish itself from other organizations established by and named for Andrew Carnegie. The Institution remains officially and legall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columbia University
Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manhattan, Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States. It is one of nine colonial colleges founded prior to the Declaration of Independence. It is a member of the Ivy League. Columbia is ranked among the top universities in the world. Columbia was established by royal charter under George II of Great Britain. It was renamed Columbia College in 1784 following the American Revolution, and in 1787 was placed under a private board of trustees headed by former students Alexander Hamilton and John Jay. In 1896, the campus was moved to its current location in Morningside Heights and renamed Columbia University. Columbia scientists and scholars have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Würzburg
The Julius Maximilian University of Würzburg (also referred to as the University of Würzburg, in German ''Julius-Maximilians-Universität Würzburg'') is a public research university in Würzburg, Germany. The University of Würzburg is one of the oldest institutions of higher learning in Germany, having been founded in 1402. The university initially had a brief run and was closed in 1415. It was reopened in 1582 on the initiative of Julius Echter von Mespelbrunn. Today, the university is named for Julius Echter von Mespelbrunn and Maximilian Joseph. The University of Würzburg is part of the U15 group of research-intensive German universities. The university is also a member of the Coimbra Group. Name Its official name is Julius-Maximilians-Universität Würzburg (or "Julius-Maximilian University of Würzburg") but it is commonly referred to as the University of Würzburg. This name is taken from Julius Echter von Mespelbrunn, Prince-Bishop of Würzburg, who reestablishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germ Cells
Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embryonic development * Cereal germ, the reproductive part of a cereal grain * Tooth germ, an aggregation of cells that eventually forms a tooth * Germ theory of disease, which states that some diseases are caused by microorganisms * Germ (mathematics), an object in a topological space that captures local properties Art and media Music * Germs (band), an American punk rock band * Germ (musician), a stage name of Tim Wright * Germ (rapper), an American rapper affiliated with Suicideboys and Pouya * "Germs" (song), by "Weird Al" Yankovic * ''The Germ'' (album), by Victim's Family Others * "Germs" (''Invader Zim''), an episode of ''Invader Zim'' * ''The Germ'' (periodical), a British art magazine published in 1850 * The Germs (comics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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