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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
Edwin Stephen Goodrich (1868-1946)
Edwin Stephen Goodrich studied the structures of animals in England during the nineteenth and twentieth centuries. Goodrich studied how animals develop to identify their parts and to establish the evolutionary relationships between different species. Goodrich established that body structures can shift their positions relative to an organism's body during evolution, and he hypothesized that body structures can share ancestry (homology) between organisms of different species, even without identical body placement.
Format: Articles
Subject: People
"Sheep Cloned by Nuclear Transfer from a Cultured Cell Line" (1996), by Keith Campbell, Jim McWhir, William Ritchie, and Ian Wilmut
In 1995 and 1996, researchers at the Roslin Institute in Edinburgh, Scotland, cloned mammals for the first time. Keith Campbell, Jim McWhir, William Ritchie, and Ian Wilmut cloned two sheep, Megan and Morag, using sheep embryo cells. The experiments indicated how to reprogram nuclei from differentiated cells to produce live offspring, and that a single population of differentiated cells could produce multiple offspring. They reported their results in the article 'Sheep Cloned by Nuclear Transfer from a Cultured Cell Line' in March 1996.
Format: Articles
Subject: Experiments
John George Children (1777–1852)
John George Children described several species of insects and animals while working at the British Museum in London, England, in the eighteenth and nineteenth centuries. Children also conducted research on chemical batteries called voltaic cells and briefly studied and manufactured gunpowder. One of the species he described, the Children’s python, or Antaresia children, was used in the twenty-first century as the subject of experiments that involved the biological cost of reproduction in snakes.
Format: Articles
Subject: People
Paul Kammerer's Experiments on the Midwife Toad (1905-1910)
In the first decade of the twentieth century, Paul Kammerer, a zoologist working at the Vivarium in Vienna, Austria, conducted research on developmental mechanisms, including a series of breeding experiments on toads (Alytes obstetricans). Kammerer claimed that his results demonstrated that organisms could transmit acquired characteristics to their offspring.
Format: Articles
Subject: Experiments
Embryonic Differentiation in Animals
Embryonic differentiation is the process of development during which embryonic cells specialize and diverse tissue structures arise. Animals are made up of many different cell types, each with specific functions in the body. However, during early embryonic development, the embryo does not yet possess these varied cells; this is where embryonic differentiation comes into play. The differentiation of cells during embryogenesis is the key to cell, tissue, organ, and organism identity.
Format: Articles
Subject: Processes
David Edwin Wildt (1950- )
David Edwin Wildt developed and applied assisted reproductive technologies to conserve rare and endangered wildlife species in the US during the twentieth and twenty-first centuries. He advocated genome resource banks to help preserve biodiversity, and he advocated for practical ethics to guide wildlife reproductive biologists when they use technology and environmental planning. Wildt often focused on the cheetah (Acinonyx jubatus), but he researched greater than fifty vertebrate species.
Format: Articles
Subject: People
St. George Jackson Mivart (1827-1900)
St. George Jackson Mivart studied animals and worked in England during the nineteenth century. He also proposed a theory of organismal development that he called individuation, and he critiqued Charles Darwin's argument for evolution by natural selection. His work on prosimians, a group of primates excluding apes and monkeys, helped scientists better investigate the Primate group.
Format: Articles
Subject: People
Alexis Carrel (1873-1944)
Alexis Carrel was a doctor and researcher who studied tissue cultures. He continued Ross Granville Harrison's research and produced many improvements in the field of tissue culture and surgery. He was the recipient of the 1912 Nobel Prize in Physiology or Medicine for his development of surgical techniques to repair blood vessels. Carrel was born on 28 June 1873 in Sainte-Foy-les-Lyon, France, to Anne-Marie Ricard and Alexis Carrel Billiard. His father died when he was five years old.
Format: Articles
Subject: People
Luc Antoine Montagnier (1932-2022)
Luc Montagnier studied viruses, the immune system, and cancer in France during the second half of the twentieth century. In his early career, Montagnier studied how cancer-causing viruses replicate and infect host cells. He received the Nobel Prize in Physiology or Medicine in 2008 for his team’s discovery that a retrovirus, human immunodeficiency virus, or HIV, was the cause of acquired immunodeficiency syndrome, or AIDS. AIDS is a chronic condition that results from HIV infection and damages the immune system.
Format: Articles
Subject: People, Processes, Experiments
The Discovery of The Dikika Baby Fossil as Evidence for Australopithecine Growth and Development
When scientists discovered a 3.3
million-year-old skeleton of a child of the human lineage (hominin) in
2000, in the village of Hadar, Ethiopia, they were able to study growth
and development of Australopithecus
afarensis, an extinct hominin species. The team of researchers,
led by Zeresenay Alemseged of the Max Planck Institute for Evolutionary
Anthropology in Leipzig, Germany, named the fossil DIK 1-1 and nicknamed
it Dikika baby after the Dikika research site. The Dikika fossil
Format: Articles
Subject: Theories
Mechanistic Realization of the Turtle Shell
Turtle morphology is unlike that of any other vertebrate. The uniqueness of the turtle's bodyplan is attributed to the manner in which the turtle's ribs are ensnared within its hard upper shell. The exact embryological and genetic mechanisms underpinning this peculiar anatomical structure are still a matter of debate, but biologists agree that the evolution of the turtle shell lies in the embryonic development of the turtle.
Format: Articles
Subject: Processes
Gavin Rylands de Beer (1899-1972)
Gavin de Beer was an English zoologist known for his contributions to evolution and embryology, in particular for showing the inadequacy of the germ layer theory as it was then proposed. He was born in London, England, on 1 November 1899, but was raised for his first thirteen years in France where his father worked for a telegraph company. He entered Magdalen College, Oxford, in 1917 but his studies were soon interrupted by World War I. After serving in the military, he returned to Oxford where he studied under Edwin Goodrich.
Format: Articles
Subject: People
Edward Drinker Cope (1840-1897)
Edward Drinker Cope studied fossils and anatomy in the US in the late nineteenth century. Based on his observations of skeletal morphology, Cope developed a novel mechanism to explain the law of parallelism, the idea that developing organisms successively pass through stages resembling their ancestors. Others had proposed the addition of new body forms at the end of an individual organism's developed as a mechanism through which new species arose, but those proposals relied on changes in the lengths of gestation or incubation.
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
"The Outgrowth of the Nerve Fiber as a Mode of Protoplasmic Movement" (1910), by Ross Granville Harrison
In "The Outgrowth of the Nerve Fiber as a Mode of Protoplasmic Movement," Ross Granville Harrison explores the growth of nerve fibers in vitro. The purpose of this experiment was to test two possible hypotheses for the growth of nerve fibers. Santiago Ramón y Cajal suggested that nerve growth is due to the extension of nerve fibers as they push through tissue. Victor Hensen's syncytial theory proposed an opposing view of nerve growth.
Format: Articles
Subject: Experiments
“Survival of Mouse Embryos Frozen to -196 ° and -269 °C” (1972), by David Whittingham, Stanley Leibo, and Peter Mazur
In 1972, David Whittingham, Stanley Leibo, and Peter Mazur published the paper, “Survival of Mouse Embryos Frozen to -196 ° and -269 °C,” hereafter, “Survival of Mouse Embryos,” in the journal Science. The study marked one of the first times that researchers had successfully cryopreserved, or preserved and stored by freezing, a mammalian embryo and later transferred that embryo to a live mouse who gave birth to viable offspring. Previously, scientists had only been successful cryopreserving single cells, like red blood cells.
Format: Articles
Subject: Experiments, Publications
Karl Ernst von Baer's Laws of Embryology
In 1828, while working at the University of Konigsberg in Konigsberg, Germany Karl Ernst von Baer proposed four laws of animal development, which came to be called von Baer's laws of embryology. With these laws, von Baer described the development (ontogeny) of animal embryos while also critiquing popular theories of animal development at the time.
Format: Articles
Subject: Theories
August Friedrich Leopold Weismann (1834-1914)
August Friedrich Leopold Weismann studied how the traits of organisms developed and evolved in a variety of organisms, mostly insects and aquatic animals, in Germany in the late nineteenth and early twentieth centuries. Weismann proposed the theory of the continuity of germ-plasm, a theory of heredity. Weismann postulated that germ-plasm was the hereditary material in cells, and parents transmitted to their offspring only the germ-plasm present in germ-cells (sperm and egg cells) rather than somatic or body cells.
Format: Articles
Subject: People
Etienne Geoffroy Saint-Hilaire (1772-1844)
Etienne Geoffroy Saint-Hilaire, commonly known as Geoffroy, studied animals, their anatomy and their embryos, and teratogens at the National Museum of Natural History in Paris, France in the eighteenth and nineteenth centuries. Geoffroy also helped develop several specialized fields in the life sciences, including experimental embryology. In his efforts to experimentally demonstrate the theory of recapitulation, Geoffroy developed techniques to intervene in the growth of embryos to see whether they would develop into different kinds of organisms.
Format: Articles
Subject: People
Richard Woltereck's Concept of Reaktionsnorm
Richard Woltereck first described the concept of Reaktionsnorm (norm of reaction) in his 1909 paper 'Weitere experimentelle Untersuchungen uber Art-veranderung, speziell uber das Wesen quantitativer Artunterschiede bei Daphniden' ('Further investigations of type variation, specifically concerning the nature of quantitative differences between varieties of Daphnia'). This concept refers to the ways in which the environment can alter the development of an organism, and its adult characteristics.
Format: Articles
Subject: Theories
Anne Laura Dorinthea McLaren (1927-2007)
Anne Laura Dorinthea McLaren was a developmental biologist known for her work with embryology in the twentieth century. McLaren was the first researcher to grow mouse embryos outside of the womb. She experimented by culturing mouse eggs and successfully developing them into embryos, leading to advancements with in vitro fertilization.
Format: Articles
Subject: People
Thomas Henry Huxley (1825-1895)
In nineteenth century Great Britain, Thomas Henry Huxley proposed connections between the development of organisms and their evolutionary histories, critiqued previously held concepts of homology, and promoted Charles Darwin's theory of evolution. Many called him Darwin's Bulldog. Huxley helped professionalize and redefine British science. He wrote about philosophy, religion, and social issues, and researched and theorized in many biological fields.
Format: Articles
Subject: People
"The Role of Maternal Mitochondria during Oogenesis, Fertilization and Embryogenesis" (2002), by James M. Cummins
James M Cummins published 'The Role of Maternal Mitochondria during Oogenesis, Fertilization and Embryogenesis' 30 January 2002 in Reproductive BioMedicine Online. In the article, Cummins examines the role of the energy producing cytoplasmic particles, or organelles called mitochondria. Humans inherit mitochondria from their mothers, and mechanisms have evolved to eliminate sperm mitochondria in early embryonic development. Mitochondria contain their own DNA (mtDNA) separate from nuclear DNA (nDNA).
Format: Articles
Subject: Publications
"In vitro Experiments on the Effects of Mouse Sarcomas 180 and 37 on the Spinal and Sympathetic Ganglia of the Chick Embryo" (1954), by Rita Levi-Montalcini, Viktor Hamburger, and Hertha Meyer
"In vitro Experiments on the Effects of Mouse Sarcomas 180 and 37 on the Spinal and Sympathetic Ganglia of the Chick Embryo" were experiments conducted by Rita Levi-Montalcini in conjunction with Viktor Hamburger and Hertha Meyer and published in Cancer Research in 1954. In this series of experiments, conducted at the University of Brazil, Levi-Montalcini demonstrated increased nerve growth by introducing specific tumors (sarcomas) to chick ganglia. Ganglia are clusters of nerve cells, from which nerve fibers emerge.
Format: Articles
Subject: Experiments