The ancients had a variety of ideas about heredity: Theophrastus proposed that male flowers caused female flowers to ripen; Hippocrates speculated that "seeds" were produced by various body parts and transmitted to offspring at the time of conception, and Aristotle thought that male and female semen mixed at conception. Aeschylus, in 458 BC, proposed the male as the parent, with the female as a "nurse for the young life sown within her". Stargate universe, see Ancient (Stargate). ... Theophrastus (Greek Θεόφραστος, 370 — about 285 BC), a native of Eressos in Lesbos, was the successor of Aristotle in the Peripatetic school. ... For other uses, see Hippocrates (disambiguation). ... This article is about the ancient Greek playwright. ...

Various hereditary mechanisms were envisaged without being properly tested or quantified. These included blending inheritance and the inheritance of acquired traits. Nevertheless, people were able to develop domestic breeds of animals as well as crops through artificial selection. The inheritance of acquired traits also formed a part of early Lamarckian ideas on evolution. Gregor Johann Mendel In Darwins time, biologists held to the theory of blending inheritance -- an offspring was an average of its parents. ... The theory of the inheritance of acquired traits was formulated by the French naturalist Jean-Baptiste Lamarck. ... This Chihuahua mix and Great Dane show the wide range of dog breed sizes created using artificial selection. ... Lamarckism is a now discredited theory of biological evolution developed by French biologist Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck in the 19th century. ...

During the 1700s, Dutch microscopist Antonie van Leeuwenhoek (1632-1723) discovered "animalcules" in the sperm of humans and other animals. Some scientists speculated they saw a "little man" (homunculus) inside each sperm. These scientists formed a school of thought known as the "spermists". They contended the only contributions of the female to the next generation were the womb in which the homunculus grew, and prenatal influences of the womb. An opposing school of thought, the ovists, believed that the future human was in the egg, and that sperm merely stimulated the growth of the egg. Ovists thought women carried eggs containing boy and girl children, and that the gender of the offspring was determined well before conception. Events and trends The Bonneville Slide blocks the Columbia River near the site of present-day Cascade Locks, Oregon with a land bridge 200 feet (60 m) high. ... Anton von Leeuwenhoek Anton van Leeuwenhoek (October 24, 1632 _ August 26, 1723) was a tradesman and scientist from Delft, in the Netherlands. ... The concept of a homunculus (Latin for little man, sometimes spelled homonculus, plural homunculi) is often used to illustrate the functioning of a system. ... A spermatozoon or spermatozoan ( spermatozoa), from the ancient Greek σπέρμα (seed) and (living being) and more commonly known as a sperm cell, is the haploid cell that is the male gamete. ...

Pangenesis was an idea that males and females formed "pangenes" in every organ. These pangenes subsequently moved through their blood to the genitals and then to the children. The concept originated with the ancient Greeks and influenced biology until little over 100 years ago. The terms "blood relative", "full-blooded", and "royal blood" are relicts of pangenesis. Francis Galton, Charles Darwin's cousin, experimentally tested and disproved pangenesis during the 1870s. Pangenesis was Charles Darwins hypothetical mechanism for heredity. ... This article does not cite any references or sources. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ... // The invention of the telephone (1876) by Alexander Graham Bell. ...

Charles Darwin: Theory of evolution

Main article: Charles Darwin

See also: Evolution

Charles Darwin proposed a theory of evolution in 1859 and one of its major problems was the lack of an underlying mechanism for heredity. Darwin believed in a mix of blending inheritance and the inheritance of acquired traits (pangenesis). Blending inheritance would lead to uniformity across populations in only a few generations and thus would remove variation from a population on which natural selection could act. This led to Darwin adopting some Lamarckian ideas in later editions of The Origin and his later biological works. Darwin's primary approach to heredity was to outline how it appeared to work (noticing that traits could be inherited which were not expressed explicitly in the parent at the time of reproduction, that certain traits could be sex-linked, etc.) rather than suggesting mechanisms. For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ... This article is about evolution in biology. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ... Year 1859 (MDCCCLIX) was a common year starting on Saturday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Thursday of the 12-day slower Julian calendar). ... Look up trait in Wiktionary, the free dictionary. ... Pangenesis was Charles Darwins hypothetical mechanism for heredity. ... The 1859 edition of On the Origin of Species First published in 1859, The Origin of Species (full title On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life) by British naturalist Charles Darwin is one of the pivotal... This article or section does not cite its references or sources. ...

Darwin's initial model of heredity was adopted by, and then heavily modified by, his cousin Francis Galton, who laid the framework for the biometric school of heredity. Galton rejected the aspects of Darwin's pangenesis model which relied on acquired traits. This article does not cite any references or sources. ... At Disney World, biometric measurements are taken of the fingers of multi-day pass users to ensure that the pass is used by the same person from day to day. ...

The inheritance of acquired traits was shown to have little basis in the 1880s when August Weismann cut the tails off many generations of mice to find that their offspring did continue to develop tails. // Development and commercial production of electric lighting Development and commercial production of gasoline-powered automobile by Karl Benz, Gottlieb Daimler and Maybach First commercial production and sales of phonographs and phonograph recordings. ... August Weismann Friedrich Leopold August Weismann (b. ... A scorpion tail The tail is the section at the rear end of an animals body; in general, the term refers to a distinct, flexible appendage to the torso. ... This article is about the rodent. ...

Gregor Mendel: Father of modern genetics

Main article: Gregor Mendel

See also: Modern evolutionary synthesis

The idea of particulate inheritance of genes can be attributed to the Moravian^[1] monk Gregor Mendel who published his work on pea plants in 1865. However, his work was not widely known and was rediscovered in 1901. It was initially assumed the Mendelian inheritance only accounted for large (qualitative) differences, such as those seen by Mendel in his pea plants — and the idea of additive effect of (quantitative) genes was not realised until R.A. Fisher's (1918) paper on The Correlation Between Relatives on the Supposition of Mendelian Inheritance. “Mendel” redirects here. ... The modern evolutionary synthesis refers to a set of ideas from several biological specialities that were brought together to form a unified theory of evolution accepted by the great majority of working biologists. ... For other uses, see Moravia (disambiguation). ... “Mendel” redirects here. ... 1865 (MDCCCLXV) is a common year starting on Sunday. ... Year 1901 (MCMI) was a common year starting on Tuesday (link will display calendar) of the Gregorian calendar (or a common year starting on Monday [1] of the 13-day-slower Julian calendar). ... Sir Ronald Aylmer Fisher, FRS (17 February 1890 – 29 July 1962) was an English statistician, evolutionary biologist, and geneticist. ... The Correlation Between Relatives on the Supposition of Mendelian Inheritance is a scientific paper by Ronald Fisher which was published in the Philosophical Transactions of the Royal Society of Edinburgh in 1918, (volume 52, pages 399—433). ...

Modern development of genetics and heredity

Main articles: History of genetics and Modern evolutionary synthesis

In the 1930s, work by Fisher and others resulted in a combination of Mendelian and biometric schools into the modern evolutionary synthesis. The modern synthesis bridged the gap between experimental geneticists and naturalists; and between both and palaeontologists, stating that:^[2][3] Gregor Mendel, the father of genetics The history of genetics is generally held to have started in 1865 when an Austrian monk, Gregor Mendel published his work on pea plants. ... The modern evolutionary synthesis refers to a set of ideas from several biological specialities that were brought together to form a unified theory of evolution accepted by the great majority of working biologists. ... The modern evolutionary synthesis refers to a set of ideas from several biological specialities that were brought together to form a unified theory of evolution accepted by the great majority of working biologists. ...

1. All evolutionary phenomena can be explained in a way consistent with known genetic mechanisms and the observational evidence of naturalists.
2. Evolution is gradual: small genetic changes, recombination ordered by natural selection. Discontinuities amongst species (or other taxa) are explained as originating gradually through geographical separation and extinction (not saltation).
3. Selection is overwhelmingly the main mechanism of change; even slight advantages are important when continued. The object of selection is the phenotype in its surrounding environment. The role of genetic drift is equivocal; though strongly supported initially by Dobzhansky, it was downgraded later as results from ecological genetics were obtained.
4. The primacy of population thinking: the genetic diversity carried in natural populations is a key factor in evolution. The strength of natural selection in the wild was greater than expected; the effect of ecological factors such as niche occupation and the significance of barriers to gene flow are all important.
5. In palaeontology, the ability to explain historical observations by extrapolation from micro to macro-evolution is proposed. Historical contingency means explanations at different levels may exist. Gradualism does not mean constant rate of change.

The idea that speciation occurs after populations are reproductively isolated has been much debated. In plants, polyploidy must be included in any view of speciation. Formulations such as 'evolution consists primarily of changes in the frequencies of alleles between one generation and another' were proposed rather later. The traditional view is that developmental biology ('evo-devo') played little part in the synthesis, but an account of Gavin de Beer's work by Gould suggests he may be an exception.^[4] For other uses, see Natural selection (disambiguation). ... Individuals in the mollusk species Donax variabilis show diverse coloration and patterning in their phenotypes. ... In population genetics, genetic drift is the statistical effect that results from the influence that chance has on the success of alleles (variants of a gene). ... Theodosius Grigorevich Dobzhansky (Russian — Феодосий Григорьевич Добржанский; sometimes anglicized to Theodore Dobzhansky; January 25, 1900 - November 11, 1975) was a noted geneticist and evolutionary biologist. ... Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ... Allele frequency is a measure of the relative frequency of an allele on a genetic locus in a population. ... Evolutionary developmental biology (often referred to as evo-devo or evolution of development) is a field of biology that compares the developmental processes of different animals in an attempt to determine the ancestral relationship between organisms and how developmental processes evolved. ... Portrait and short biography of Gavin de Beer from the back cover of his 1945 book Escape to Switzerland Sir Gavin Rylands de Beer FRS (1899–1972) was a British evolutionary embryologist, director of the British Museum (Natural History) and president of the Linnean Society. ... Stephen Jay Gould Stephen Jay Gould (September 10, 1941 – May 20, 2002) was a New York-born American paleontologist, evolutionary biologist, and historian of science. ...

Almost all aspects of the synthesis have been challenged at times, with varying degrees of success. There is no doubt, however, that the synthesis was a great landmark in evolutionary biology. It cleared up many confusions, and was directly responsible for stimulating a great deal of research in the post-WWII era. German soldiers at the Battle of Stalingrad World War II was the most extensive and costly armed conflict in the history of the world, involving the great majority of the worlds nations, being fought simultaneously in several major theatres, and costing tens of millions of lives. ...

Trofim Lysenko however caused a backlash of what is now called Lysenkoism in the Soviet Union when he emphasised Lamarckian ideas on the inheritance of acquired traits. This movement affected agricultural research and led to food shortages in the 1960s and seriously affected the USSR. Trofim Denisovich Lysenko (Russian: Трофи́м Дени́сович Лысе́нко) (September 29, 1898–November 20, 1976) was a Soviet politician who made pretense of being a biologist. ... Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ... Lamarckism is a now discredited theory of biological evolution developed by French biologist Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck in the 19th century. ... The theory of the inheritance of acquired traits was formulated by the French naturalist Jean-Baptiste Lamarck. ... The 1960s decade refers to the years from the beginning of 1960 to the end of 1969. ...

See also

Look up Heredity in
Wiktionary, the free dictionary.

• Genetics

Wiktionary (a portmanteau of wiki and dictionary) is a multilingual, Web-based project to create a free content dictionary, available in over 151 languages. ... This article is about the general scientific term. ...

External links

• Stanford Encyclopedia of Philosophy entry on Heredity and Heritability
• Encyclopaedia Britannica, Heredity

References