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Displaying 101 - 125 of 244 items.

Wilhelm August Oscar Hertwig (1849-1922)

Wilhelm August Oscar Hertwig contributed to embryology through his studies of cells in development and his discovery that only one spermatozoon is necessary to fertilize an egg. He was born 21 April 1849 to Elise Trapp and Carl Hertwig in Hessen, Germany. After his brother Richard was born the family moved to Muhlhausen in Thuringen where the boys were educated. The two brothers later attended the university in Jena from 1868 to 1888 and studied under Ernst Haeckel, who later convinced Hertwig to leave chemistry and pursue medicine.

Format: Articles

Subject: People

Susceptibility Assay

Charles Manning Child designed an experimental test, the susceptibility assay, to measure the effects of different toxins on developmental processes. The susceptibility assay measured an organism s vulnerability to death when it was submerged in a noxious solution. The assay involved immersing an organism in a solution that contained a depressant or inhibitory substance, such as alcohol, and then measuring the responses of the organism. Child interpreted these measurements as revealing information about the relative levels of metabolic activity within the organism.

Format: Articles

Subject: Technologies

Ross Granville Harrison (1870-1959)

A pioneer in experimental embryology, Ross Granville Harrison made numerous discoveries that advanced biology. One of the most significant was his adaptation of the hanging drop method from bacteriology to carry out the first tissue culture. This method allowed for further studies in embryology as well as experimental improvements in oncology, virology, genetics, and a number of other fields.

Format: Articles

Subject: People

James William Kitching (1922-2003)

James William Kitching collected and studied fossils of dinosaurs and early humans in the twentieth century. He worked at the Bernard Price Institute for Paleontological Research in South Africa. During the fifty-three years he worked at the institute, Kitching spent eighteen of those in the field uncovering fossils. Kitching recovered fossils of early human ancestors, later called Australopithecines, as well as fossils of dinosaurs and ancient mammals. When he died in 2003, the Bernard Price Institute housed one of the largest fossil collections in the southern hemisphere.

Format: Articles

Subject: People

Roy Chapman Andrews (1884-1960)

Roy Chapman Andrews traveled the world studying fossils, from mammals to dinosaurs, during the first half of the twentieth century. Andrews worked and collected fossil specimens for the American Museum of Natural History (AMNH) in New York City, New York. Throughout his career, Andrews collected bones of many animal species, including a previously unknown species of a horned, herbivorous dinosaur, later named Proceratops andrewsi in his honor. Andrews published widely read narratives about his travels and field experiences, such as On the Trail of Ancient Man and Across Mongolian Plains.

Format: Articles

Subject: People

Dana Louise Raphael (1926–2016)

Dana Louise Raphael was an anthropologist and breastfeeding advocate in the US during the twentieth century. After she was unable to breastfeed her own infant, Raphael began to research why breastfeeding was more common in other cultures than in the US. As part of that research, Raphael cofounded the Human Lactation Center, where she studied the breastfeeding habits of mothers around the world. Through that research, she coordinated with formula manufacturers to educate women on the benefits of breastfeeding and formula supplementation to reduce infant mortality in developing nations.

Format: Articles

Subject: People

Torsten Wiesel (1924– )

Torsten Nils Wiesel studied visual information processing and development in the US during the twentieth century. He performed multiple experiments on cats in which he sewed one of their eyes shut and monitored the response of the cat’s visual system after opening the sutured eye. For his work on visual processing, Wiesel received the Nobel Prize in Physiology or Medicine in 1981 along with David Hubel and Roger Sperry.

Format: Articles

Subject: People

Henrietta Lacks (1920–1951)

Henrietta Lacks, born Loretta Pleasant, had terminal cervical cancer in 1951, and was diagnosed at The Johns Hopkins University in Baltimore, Maryland, where researchers collected and stored her cancer cells. Those cells went on to become the first immortal human cell line, which the researchers named HeLa. An immortal cell line is an atypical cluster of cells that continuously multiply on their own outside of the organism from which they came, often due to a mutation.

Format: Articles

Subject: People, Ethics

Ectopic Pregnancy

Many difficulties can arise with a pregnancy even after the sperm successfully fertilizes the oocyte. A major problem occurs if the fertilized egg tries to implant before reaching its normal implantation site, the uterus. An ectopic pregnancy occurs when a fertilized egg implants anywhere other than in the uterus, most commonly in the fallopian tubes. Ectopic pregnancies cannot continue to term, so a physician must remove the developing embryo as early as possible.

Format: Articles

Subject: Disorders, Processes, Reproduction

John Spangler Nicholas (1895-1963)

John Spangler Nicholas, an American biologist, was born on 10 March 1895 in Allegheny, Pennsylvania. He was the only child of Elizabeth Ellen Spangler, a teacher, and Samuel Trauger Nicholas, a Lutheran minister. Nicholas held myriad administrative positions throughout his life and his contributions to biology spanned several sub-disciplines, but his most notable accomplishments were in the field of embryology.

Format: Articles

Subject: People

Nettie Maria Stevens (1861-1912)

Multiple theories about what determines sex were tested at the turn of the twentieth century. By experimenting on germ cells, cytologist Nettie Maria Stevens collected evidence to support the connection between heredity and the sex of offspring. Stevens was able to interpret her data to conclude that chromosomes have a role in sex determination during development. For her time, she was an emerging breed: a woman of science making the leap from the world of data collection to that of male-dominated interpretive work.

Format: Articles

Subject: People, Reproduction

The Source-Sink Model

The source-sink model, first proposed by biologist Francis Crick in 1970, is a theoretical system for how morphogens distribute themselves across small fields of early embryonic cells. A morphogen is a substance that determines the fate and phenotype of a group of cells through a concentration gradient of itself across that group. Crick’s theory has been experimentally confirmed with several morphogens, most notably with the protein bicoid , the first discovered morphogen. The model provides a theoretical structure for the understanding of some features of early embryonic development.

Format: Articles

Subject: Theories

Edwin Grant Conklin (1863-1952)

Edwin Grant Conklin was born in Waldo, Ohio, on 24 November 1863 to parents Nancy Maria Hull and Dr. Abram V. Conklin. Conklin's family was very religious and he seriously considered a theistic path before choosing a career in academics. Conklin's scientific work was primarily in the areas of embryology, cytology, and morphology, though many questions regarding the relationships between science, society, and philosophy had an influence on both his writings and academic lectures.

Format: Articles

Subject: People

De Formato Foetu (c. 1600), by Girolamo Fabrici

The embryological treatise De formato foetu (The Formed Fetus) was written by anatomist and embryologist Girolamo Fabrici. There is no conclusive evidence regarding the first date of publication and what is listed on many copies ranges from 1600-1620, with speculation that the dates were altered by hand. Most forms of the book are dated 1600 and were issued by Franciscus Bolzetta who sold many copies in Venice and whose name appears on the engraved title-page. There is also verification of the book being printed in Padua by Laurentius Pasquatus in 1604.

Format: Articles

Subject: Publications

De Formatione Ovi et Pulli (1621), by Girolamo Fabrici

The embryological treatise De formatione ovi et pulli (On the Formation of the Egg and of the Chick) was written by anatomist and embryologist Girolamo Fabrici and published in Padua posthumously in 1621. The book was edited by Joahannes Prevotius and is separated into two parts that describe Fabrici's observations and assumptions on embryology and combine the traditional knowledge of his predecessors with his own first-hand anatomical observations.

Format: Articles

Subject: Publications

Golden Rice

Golden Rice was engineered from normal rice by Ingo Potrykus and Peter Beyer in the 1990s to help improve human health. Golden Rice has an engineered multi-gene biochemical pathway in its genome. This pathway produces beta-carotene, a molecule that becomes vitamin A when metabolized by humans. Ingo Potrykus worked at the Swiss Federal Institute of Technology in Zurich, Switzerland, and Peter Beyer worked at University of Freiburg, in Freiburg, Germany. The US Rockefeller Foundation supported their collaboration.

Format: Articles

Subject: Organisms, Legal

Hans Adolf Eduard Driesch (1867-1941)

Although educated as a scientist who studied with both August Weismann and Ernst Heinrich Haeckel, Hans Adolf Eduard Driesch was first employed as a professor of philosophy and became a strong proponent of vitalism. Driesch was born on 28 October 1867, the only child of Josefine Raudenkolb and Paul Driesch. He grew up in a wealthy merchant family in Hamburg, Germany, where he was educated at the humanistic Gymnasium Gelehrtenschule des Johanneums that had been founded by a friend of Martin Luther.

Format: Articles

Subject: People

Katharine McCormick (1876-1967)

Katharine Dexter McCormick, who contributed the majority of funding for the development of the oral contraceptive pill, was born to Josephine and Wirt Dexter on 27 August 1875 in Dexter, Michigan. After growing up in Chicago, Illinois, she attended the Massachusetts Institute of Technology (MIT), where she graduated in 1904 with a BS in biology. That same year, she married Stanley McCormick, the son of Cyrus McCormick, inventor and manufacturer of the mechanized reaper.

Format: Articles

Subject: People, Ethics, Reproduction

George Linius Streeter (1873-1948)

George Linius Streeter was born on 12 January 1873 in Johnstown, New York, to Hannah Green Anthony and George Austin Streeter. He completed his undergraduate studies at Union College in 1895 and received his MD degree from the College of Physicians and Surgeons of Columbia University in 1899. At Columbia, Professor George S. Huntington sparked Streeter's interest in anatomy, and Streeter also interned at Roosevelt Hospital in New York City. He then went on to Albany to teach anatomy at the Albany Medical College and to work with neurologist Henry Hun.

Format: Articles

Subject: People

Jane Marion Oppenheimer (1911-1966)

Jane Marion Oppenheimer, embryologist and historian of science and medicine, was born on 19 September 1911 in Philadelphia, Pennsylvania, to Sylvia Stern and James H. Oppenheimer. After studying zoology at Bryn Mawr College, Oppenheimer received her AB degree in 1932. Oppenheimer received her PhD in embryology at Yale University in 1935 and worked as a research fellow from 1935-1936. While at Yale she was influenced by the work of Ross Granville Harrison and John Spangler Nicholas, the latter of whom was Oppenheimer's PhD advisor.

Format: Articles

Subject: People

Lennart Nilsson (1922- )

Lennart Nilsson is a world-renowned photojournalist recognized for his exploratory images of the inside of the human body. Throughout his career, Nilsson has received a great deal of publicity for his images documenting the human reproductive system and the morphology of viruses. His photography was the first to capture early human development and the developmental stages of embryos and fetuses. These images have helped shape the way the public visualizes development.

Format: Articles

Subject: People, Outreach, Reproduction

Lazzaro Spallanzani (1729-1799)

Lazzaro Spallanzani's imaginative application of experimental methods, mastery of microscopy, and wide interests led him to significant contributions in natural history, experimental biology, and physiology. His detailed and thoughtful observations illuminated a broad spectrum of problems ranging from regeneration to the genesis of thunderclouds.

Format: Articles

Subject: People

The Mechanistic Conception of Life (1912), by Jacques Loeb

Jacques Loeb published The Mechanistic Conception of Life in 1912. Loeb's goal for the book was to further disseminate his explanations of organic processes, such as embryonic development and organisms orientations to their environments, which relied on physics and chemistry. Loeb also wanted to provide an alternative explanatory framework to vitalism and what he called romantic evolutionism, then both widespread.

Format: Articles

Subject: Publications

Jacques Loeb (1859-1924)

Jacques Loeb experimented on embryos in Europe and the United States at the end of the nineteenth and beginning of the twentieth centuries. Among the first to study embryos through experimentation, Loeb helped found the new field of experimental embryology. Notably, Loeb showed scientists how to create artificial parthenogenesis, thus refuting the idea that spermatozoa alone were necessary to develop eggs into embryos and confirming the idea that the chemical constitution of embryos environment affected their development.

Format: Articles

Subject: People

The Biological Bulletin

From 1886 to 1889 Charles Otis Whitman was director of the Allis Lake Laboratory in Milwaukee, Wisconsin. The lab was established by Edward Phelps Allis, Jr. to provide a place for biological research separate from a university setting and a place where an independent scholar like Allis himself could work. Allis had hired Whitman as an instructor to establish the lab, direct it, and lead a research program there. The lab lasted for eight years, attracted several researchers, and the papers that came out of the lab included a focus on embryology.

Format: Articles

Subject: Publications