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Biogenesis
Spontaneous generation is a superseded scientific theory that held that living creatures could arise from nonliving matter and that such processes were commonplace and regular. It was hypothesized that certain forms, such as fleas, could arise from inanimate matter such as dust, or that maggots could arise from dead flesh. The doctrine of spontaneous generation was coherently synthesized by Aristotle, who compiled and expanded the work of earlier natural philosophers and the various ancient explanations for the appearance of organisms. Spontaneous generation was taken as scientific fact for two millennia. Though challenged in the 17th and 18th centuries by the experiments of Francesco Redi and Lazzaro Spallanzani, it was not discredited until the work of the French chemist Louis Pasteur and the Irish physicist John Tyndall in the mid-19th century. Rejection of spontaneous generation is no longer controversial among biologists. By the middle of the 19th century, experiments by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Origin Of Life
In biology, abiogenesis (from a- 'not' + Greek bios 'life' + genesis 'origin') or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single event, but an evolutionary process of increasing complexity that involved the formation of a habitable planet, the prebiotic synthesis of organic molecules, molecular self-replication, self-assembly, autocatalysis, and the emergence of cell membranes. Many proposals have been made for different stages of the process. The study of abiogenesis aims to determine how pre-life chemical reactions gave rise to life under conditions strikingly different from those on Earth today. It primarily uses tools from biology and chemistry, with more recent approaches attempting a synthesis of many sciences. Life functions through the specialized chemistry of carbon and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abiogenesis
In biology, abiogenesis (from a- 'not' + Greek bios 'life' + genesis 'origin') or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single event, but an evolutionary process of increasing complexity that involved the formation of a habitable planet, the prebiotic synthesis of organic molecules, molecular self-replication, self-assembly, autocatalysis, and the emergence of cell membranes. Many proposals have been made for different stages of the process. The study of abiogenesis aims to determine how pre-life chemical reactions gave rise to life under conditions strikingly different from those on Earth today. It primarily uses tools from biology and chemistry, with more recent approaches attempting a synthesis of many sciences. Life functions through the specialized chemistry of carbon and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexander Oparin
Alexander Ivanovich Oparin (russian: Александр Иванович Опарин; – April 21, 1980) was a Soviet biochemist notable for his theories about the origin of life, and for his book ''The Origin of Life''. He also studied the biochemistry of material processing by plants and enzyme reactions in plant cells. He showed that many food production processes were based on biocatalysis and developed the foundations for industrial biochemistry in the USSR. Life Born in Uglich in 1894, Oparin graduated from the Moscow State University in 1917 and became a professor of biochemistry there in 1927. Many of his early papers were about plant enzymes and their role in metabolism. In 1924 he put forward a hypothesis suggesting that life on Earth developed through a gradual chemical evolution of carbon-based molecules in the Earth's primordial soup. In 1935, along with academician Alexey Bakh, he founded the Biochemistry Institute of the Soviet Academy of Sciences. In 1939, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which in his view is intentional, whereas natural selection is not. Genetic diversity, Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits. The environment of a genome includes the molecular biology in the Cell (biology), cell, other cells, other individuals, populations, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Francesco Redi
Francesco Redi (18 February 1626 – 1 March 1697) was an Italian physician, naturalist, biologist, and poet. He is referred to as the "founder of experimental biology", and as the "father of modern parasitology". He was the first person to challenge the theory of spontaneous generation by demonstrating that maggots come from eggs of flies. Having a doctoral degree in both medicine and philosophy from the University of Pisa at the age of 21, he worked in various cities of Italy. A rationalist of his time, he was a critic of verifiable myths, such as spontaneous generation. His most famous experiments are described in his magnum opus ''Esperienze intorno alla generazione degl'insetti'' (''Experiments on the Generation of Insects''), published in 1668. He disproved that vipers drink wine and could break glasses, and that their venom was poisonous when ingested. He correctly observed that snake venoms were produced from the fangs, not the gallbladder, as was believed. He was also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lazzaro Spallanzani
Lazzaro Spallanzani (; 12 January 1729 – 11 February 1799) was an Italian Catholic priest (for which he was nicknamed Abbé Spallanzani), biologist and physiologist who made important contributions to the experimental study of bodily functions, animal reproduction, and animal echolocation. His research on biogenesis paved the way for the downfall of the theory of spontaneous generation, a prevailing idea at the time that organisms develop from inanimate matters, though the final death blow to the idea was dealt by French scientist Louis Pasteur a century later. His most important works were summed up in his book ''Experiencias Para Servir a La Historia de La Generación De Animales y Plantas'' (''Experiences to Serve to the History of the Generation of Animals and Plants''), published in 1786. Among his contributions were experimental demonstrations of fertilisation between ova and spermatozoa, and ''in vitro'' fertilisation''.'' Biography Spallanzani was born in Scandian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenomena
A phenomenon ( : phenomena) is an observable event. The term came into its modern philosophical usage through Immanuel Kant, who contrasted it with the noumenon, which ''cannot'' be directly observed. Kant was heavily influenced by Gottfried Wilhelm Leibniz in this part of his philosophy, in which phenomenon and noumenon serve as interrelated technical terms. Far predating this, the ancient Greek Pyrrhonist philosopher Sextus Empiricus also used ''phenomenon'' and ''noumenon'' as interrelated technical terms. Common usage In popular usage, a ''phenomenon'' often refers to an extraordinary event. The term is most commonly used to refer to occurrences that at first defy explanation or baffle the observer. According to the ''Dictionary of Visual Discourse'':In ordinary language 'phenomenon/phenomena' refer to any occurrence worthy of note and investigation, typically an untoward or unusual event, person or fact that is of special significance or otherwise notable. Philosophy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arche
''Arche'' (; grc, ἀρχή; sometimes also transcribed as ''arkhé'') is a Greek word with primary senses "beginning", "origin" or "source of action" (: from the beginning, οr : the original argument), and later "first principle" or "element". By extension, it may mean "first place", "method of government", "empire, realm", "authorities" (in plural: ), "command". The first principle or element corresponds to the "ultimate underlying substance" and "ultimate indemonstrable principle". In the philosophical language of the archaic period (8th to 6th century BC), ''arche'' (or ''archai'') designates the source, origin or root of things that exist. In ancient Greek philosophy, Aristotle foregrounded the meaning of ''arche'' as the element or principle of a thing, which although undemonstrable and intangible in itself, provides the conditions of the possibility of that thing. Mythical cosmogonies In the mythical Greek cosmogony of Hesiod (8th to 7th century BC), the origin of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anaximander
Anaximander (; grc-gre, Ἀναξίμανδρος ''Anaximandros''; ) was a pre-Socratic Greek philosopher who lived in Miletus,"Anaximander" in ''Chambers's Encyclopædia''. London: George Newnes, 1961, Vol. 1, p. 403. a city of Ionia (in modern-day Turkey). He belonged to the Milesian school and learned the teachings of his master Thales. He succeeded Thales and became the second master of that school where he counted Anaximenes and, arguably, Pythagoras amongst his pupils. Little of his life and work is known today. According to available historical documents, he is the first philosopher known to have written down his studies, although only one fragment of his work remains. Fragmentary testimonies found in documents after his death provide a portrait of the man. Anaximander was an early proponent of science and tried to observe and explain different aspects of the universe, with a particular interest in its origins, claiming that nature is ruled by laws, just like human soc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substance Theory
Substance theory, or substance–attribute theory, is an ontological theory positing that objects are constituted each by a ''substance'' and properties borne by the substance but distinct from it. In this role, a substance can be referred to as a ''substratum'' or a ''thing-in-itself''. ''Substances'' are particulars that are ontologically independent: they are able to exist all by themselves. Another defining feature often attributed to substances is their ability to ''undergo changes''. Changes involve something existing ''before'', ''during'' and ''after'' the change. They can be described in terms of a persisting substance gaining or losing properties. ''Attributes'' or ''properties'', on the other hand, are entities that can be exemplified by substances. Properties characterize their bearers, they express what their bearer is like. ''Substance'' is a key concept in ontology and metaphysics, which may be classified into monist, dualist, or pluralist varieties according to how ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Apeiron (cosmology)
''Apeiron'' (; ) is a Greek word meaning "(that which is) unlimited," "boundless", "infinite", or "indefinite" from ''a-'', "without" and ''peirar'', "end, limit", "boundary", the Ionic Greek form of ''peras'', "end, limit, boundary". Origin of everything The ''apeiron'' is central to the cosmological theory created by Anaximander, a 6th-century BC pre-Socratic Greek philosopher whose work is mostly lost. From the few existing fragments, we learn that he believed the beginning or ultimate reality (''arche'') is eternal and infinite, or boundless (''apeiron''), subject to neither old age nor decay, which perpetually yields fresh materials from which everything we can perceive is derived. ''Apeiron'' generated the opposites (hot–cold, wet–dry, etc.) which acted on the creation of the world (cf. Heraclitus). Everything is generated from ''apeiron'' and then it is destroyed by going back to ''apeiron'', according to necessity. He believed that infinite worlds are generated f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eucestoda
Eucestoda, commonly referred to as tapeworms, is the larger of the two Class (biology), subclasses of flatworms in the class Cestoda (the other subclass is Cestodaria). Larvae have six posterior hooks on the scolex (head), in contrast to the ten-hooked Cestodaria. All tapeworms are Parasitism, endoparasites of vertebrates, living in the digestive tract or related ducts. Examples are the pork tapeworm (''Taenia solium'') with a human Host (biology)#Definitive and secondary hosts, definitive host, and pigs as the Host (biology)#Definitive and secondary hosts, secondary host, and ''Moniezia expansa'', the definitive hosts of which are ruminants. Body structure Adult Eucestoda have a white-opaque dorso-ventrally flattened appearance, and are elongated, ranging in length from a few millimeters to 25 meters. Almost all members, except members of the orders Caryophyllidea and Spathebothriidea, are polyzoism, polyzoic with repeated sets of reproductive organs down the body length, and al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
