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Morphogenetic Field
In the developmental biology of the early twentieth century, a morphogenetic field is a research hypothesis and a discrete region of cells in an embryo. The term ''morphogenetic field'' conceptualizes the scientific experimental finding that an embryonic group of cells, for example a forelimb bud, could be transplanted to another part of the embryo and in ongoing individual development still give rise to a forelimb at an odd place of the organism. And it describes a group of embryonic cells able to respond to localized biochemical signals − called '' field'' − leading to the genesis of morphological structures: tissues, organs, or parts of an organism. The spatial and temporal extents of such a region of embryonic stem cells are dynamic, and within it is a collection of interacting cells out of which a particular tissue, organ, or body part is formed. As a group, the cells within a morphogenetic field in an embryo are constrained: thus, cells in a limb field ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Morphogenetic
Morphogenesis (from the Greek ''morphê'' shape and ''genesis'' creation, literally "the generation of form") is the biological process that causes a cell, tissue or organism to develop its shape. It is one of three fundamental aspects of developmental biology along with the control of tissue growth and patterning of cellular differentiation. The process controls the organized spatial distribution of cells during the embryonic development of an organism. Morphogenesis can take place also in a mature organism, such as in the normal maintenance of tissue by stem cells or in regeneration of tissues after damage. Cancer is an example of highly abnormal and pathological tissue morphogenesis. Morphogenesis also describes the development of unicellular life forms that do not have an embryonic stage in their life cycle. Morphogenesis is essential for the evolution of new forms. Morphogenesis is a mechanical process involving forces that generate mechanical stress, strain, and movem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Imaginal Disc
An imaginal disc is one of the parts of a holometabolous insect larva that will become a portion of the outside of the adult insect during the pupal transformation to the imago. Contained within the body of the larva, there are pairs of discs that will form, for instance, the wings or legs or antennae or other structures in the adult. The role of the imaginal disc in insect development was first elucidated by Jan Swammerdam. During the pupal stage, many larval structures are broken down, and adult structures, including the discs, undergo rapid development. Each disc everts and elongates, with the central portion of the disc becoming the distal part of whichever appendage it is forming: the wing, leg, antenna, etc. During the larval stage, the cells in the growing disc appear undifferentiated, but their developmental fate in the adult is already determined. The experiment that demonstrates this developmental commitment is to take an imaginal disc from a third instar larva, abo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Scott F
Scott may refer to: Places Canada * Scott, Quebec, municipality in the Nouvelle-Beauce regional municipality in Quebec * Scott, Saskatchewan, a town in the Rural Municipality of Tramping Lake No. 380 * Rural Municipality of Scott No. 98, Saskatchewan United States * Scott, Arkansas * Scott, Georgia * Scott, Indiana * Scott, Louisiana * Scott, Missouri * Scott, New York * Scott, Ohio * Scott, Wisconsin (other) (several places) * Fort Scott, Kansas * Great Scott Township, St. Louis County, Minnesota * Scott Air Force Base, Illinois * Scott City, Kansas * Scott City, Missouri * Scott County (other) (various states) * Scott Mountain (other) (several places) * Scott River, in California * Scott Township (other) (several places) Elsewhere * 876 Scott, minor planet orbiting the Sun * Scott (crater), a lunar impact crater near the south pole of the Moon *Scott Conservation Park, a protected area in South Australia Lists * Scott P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Homeobox
A homeobox is a Nucleic acid sequence, DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development. Mutations in a homeobox may change large-scale anatomical features of the full-grown organism. Homeoboxes are found within genes that are involved in the regulation of patterns of anatomical development (morphogenesis) in animals, fungus, fungi, plants, and numerous single cell eukaryotes. Homeobox genes encode homeodomain protein products that are transcription factors sharing a characteristic protein fold structure that binds DNA to regulate expression of target genes. Homeodomain proteins regulate gene expression and cell differentiation during early embryonic development, thus mutations in homeobox genes can cause developmental disorders. Homeosis is a term coined by William Bateson to describe the outright replacement of a discrete body part with another body part, e.g. antennapedia—replacement of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hypothesis
A hypothesis (: hypotheses) is a proposed explanation for a phenomenon. A scientific hypothesis must be based on observations and make a testable and reproducible prediction about reality, in a process beginning with an educated guess or thought. If a hypothesis is repeatedly independently demonstrated by experiment to be true, it becomes a scientific theory. In colloquial usage, the words "hypothesis" and "theory" are often used interchangeably, but this is incorrect in the context of science. A working hypothesis is a provisionally-accepted hypothesis used for the purpose of pursuing further progress in research. Working hypotheses are frequently discarded, and often proposed with knowledge (and warning) that they are incomplete and thus false, with the intent of moving research in at least somewhat the right direction, especially when scientists are stuck on an issue and brainstorming ideas. A different meaning of the term ''hypothesis'' is used in formal l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Modern Synthesis (20th Century)
The modern synthesis was the early 20th-century synthesis of Charles Darwin's theory of evolution and Gregor Mendel's ideas on Mendelian inheritance, heredity into a joint mathematical framework. Julian Huxley coined the term in his 1942 book, ''Evolution: The Modern Synthesis''. The synthesis combined the ideas of natural selection, Mendelian inheritance, Mendelian genetics, and population genetics. It also related the broad-scale macroevolution seen by paleontology, palaeontologists to the small-scale microevolution of local population, populations. The synthesis was defined differently by its founders, with Ernst Mayr in 1959, G. Ledyard Stebbins in 1966, and Theodosius Dobzhansky in 1974 offering differing basic postulates, though they all include natural selection, working on heritable variation supplied by mutation. Other major figures in the synthesis included E. B. Ford, Bernhard Rensch, Ivan Schmalhausen, and George Gaylord Simpson. An early event in the modern synthesi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Thomas Hunt Morgan
Thomas Hunt Morgan (September 25, 1866 – December 4, 1945) was an Americans, American evolutionary biologist, geneticist, Embryology, embryologist, and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries elucidating the role that the chromosome plays in heredity. Morgan received his Ph.D. from Johns Hopkins University in zoology in 1890 and researched embryology during his tenure at Bryn Mawr College, Bryn Mawr. Following the rediscovery of Mendelian inheritance in 1900, Morgan began to study the genetic characteristics of the fruit fly ''Drosophila melanogaster''. In his famous Fly Room at Columbia University's Schermerhorn Hall, Morgan demonstrated that genes are carried on chromosomes and are the mechanical basis of heredity. These discoveries formed the basis of the modern science of genetics. During his distinguished career, Morgan wrote List of books by Thomas Hunt Morgan, 22 books and 370 scientific papers. As a result of his work, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Ontogeny
Ontogeny (also ontogenesis) is the origination and development of an organism (both physical and psychological, e.g., moral development), usually from the time of fertilization of the ovum, egg to adult. The term can also be used to refer to the study of the entirety of an organism's lifespan. Ontogeny is the developmental history of an organism within its own lifetime, as distinct from phylogeny, which refers to the evolutionary history of a species. Another way to think of ontogeny is that it is the process of an organism going through all of the developmental stages over its lifetime. The developmental history includes all the developmental events that occur during the existence of an organism, beginning with the changes in the egg at the time of fertilization and events from the time of birth or hatching and afterward (i.e., growth, remolding of body shape, development of secondary sexual characteristics, etc.). While developmental (i.e., ontogenetic) processes can influen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hans Adolf Eduard Driesch
Hans Adolf Eduard Driesch (28 October 1867 – 17 April 1941) was a German biologist and philosopher from Bad Kreuznach. He is most noted for his early experimental work in embryology and for his neo-vitalism, vitalist philosophy of entelechy. He has also been credited with performing the first artificial 'cloning' of an animal in the 1880s, although this claim is dependent on how one defines cloning. Early years Driesch was educated at the Gelehrtenschule des Johanneums. He began to study medicine in 1886 under August Weismann at the University of Freiburg. In 1887 he attended the University of Jena under Ernst Haeckel, Oscar Hertwig and Christian Ernst Stahl. In 1888 he studied physics and chemistry at the University of Munich. He received his doctorate in 1889. He travelled widely on field and study trips and lecture-tours, visiting Plymouth, India, Zurich and Leipzig where, in 1894, he published his ''Analytische Theorie der organischen Entwicklung'' or ''Analytic Theory of O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Entelechy
In philosophy, potentiality and actuality are a pair of closely connected principles which Aristotle used to analyze motion, causality, ethics, and physiology in his ''Physics'', ''Metaphysics'', '' Nicomachean Ethics'', and '' De Anima''. The concept of potentiality, in this context, generally refers to any "possibility" that a thing can be said to have. Aristotle did not consider all possibilities the same, and emphasized the importance of those that become real of their own accord when conditions are right and nothing stops them. Actuality, in contrast to potentiality, is the motion, change or activity that represents an exercise or fulfillment of a possibility, when a possibility becomes real in the fullest sense. Both these concepts therefore reflect Aristotle's belief that events in nature are not all natural in a true sense. As he saw it, many things happen accidentally, and therefore not according to the natural purposes of things. These concepts, in modified forms, re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Paul Alfred Weiss
Paul Alfred Weiss (March 21, 1898 – September 8, 1989) was an Austrian biologist who specialised in morphogenesis, development, differentiation and neurobiology. A teacher, experimenter and theorist, he made a lasting contribution to science in his lengthy career, throughout which he sought to encourage specialists in different fields to meet and share insights. Life and career Paul Weiss was born in Vienna, the son of a Jewish couple, Carl S. Weiss, a businessman, and Rosalie Kohn Weiss. His background favoured music, poetry, and philosophy – Weiss himself was a violinist – but an uncle encouraged an interest in science. Weiss received his baccalaureate in 1916. After the end of the First World War, having served for three years as an officer in the artillery, he commenced studies in mechanical engineering at the Technische Hochschule in Vienna, (now Vienna University of Technology). He then shifted his focus to biology with a minor in physics. He absorbed the studie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hans Spemann
Hans Spemann (; 27 June 1869 – 9 September 1941) was a German embryologist who was awarded a Nobel Prize in Physiology or Medicine in 1935 for his student Hilde Mangold's discovery of the effect now known as embryonic induction, an influence, exercised by various parts of the embryo, that directs the development of groups of cells into particular tissues and organs, one of the first steps towards cloning. Spemann added his name as an author to Hilde Mangold's dissertation (although she objected) and won a Nobel Prize for her work. Biography Hans Spemann was born in Stuttgart, the eldest son of publisher Wilhelm Spemann and his wife Lisinka, née Hoffman. After he left school in 1888 he spent a year in his father's business, then, in 1889–1890, he did military service in the Kassel Hussars followed by a short time as a bookseller in Hamburg. In 1891 he entered the University of Heidelberg where he studied medicine, taking his preliminary examination in 1893. There he met th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
