Ronald Fisher
| Ronald Fisher |
|---|
 |
| Ronald Fisher em outros projetos: |
Sir Ronald Fisher (17 de fevereiro de 1890 - 29 de julho de 1962), foi um biólogo evolucionista, geneticista e estatístico.
A Teoria Genética da Seleção Natural (1930)[editar]
- Nenhum biólogo prático interessado na reprodução sexuada seria levado a estudar as consequências detalhadas sofridas por organismos com três ou mais sexos; no entanto, o que mais ele deveria fazer se quisesse compreender por que os sexos são, de fato, sempre dois?
- - No practical biologist interested in sexual reproduction would be led to work out the detailed consequences experienced by organisms having three or more sexes; yet what else should he do if he wishes to understand why the sexes are, in fact, always two?
- - Prefácio, pág. ix.
- - No practical biologist interested in sexual reproduction would be led to work out the detailed consequences experienced by organisms having three or more sexes; yet what else should he do if he wishes to understand why the sexes are, in fact, always two?
- Podemos, conseqüentemente, enunciar o teorema fundamental da Seleção Natural na forma: A taxa de aumento na aptidão de qualquer organismo em qualquer momento é igual à sua variância genética na aptidão naquele momento.
- - We may consequently state the fundamental theorem of Natural Selection in the form : The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.
- - Definindo o teorema fundamental da seleção natural, cap. 2, pág. 35.
- - We may consequently state the fundamental theorem of Natural Selection in the form : The rate of increase in fitness of any organism at any time is equal to its genetic variance in fitness at that time.
Anos 1940[editar]
- Ele é um político ambicioso, de um tipo que provavelmente se tornará predominante num sistema declaradamente guiado por uma ideologia rígida, que espera usar os dogmas ideológicos com os quais encontra os seus colegas comprometidos como alavancas para o seu próprio avanço no partido e no Estado.
- - He is an ambitious politician of a type likely to become prevalent in a system avowedly guided by a rigid ideology, who hopes to use the ideological dogmas to which he finds his colleagues committed as levers for his own advancement in the party and in the state.
- - "What sort of man is Lysenko?", Listener, 40: 874-875 (1948)
- - He is an ambitious politician of a type likely to become prevalent in a system avowedly guided by a rigid ideology, who hopes to use the ideological dogmas to which he finds his colleagues committed as levers for his own advancement in the party and in the state.
Anos 1950[editar]
- A seleção natural é um mecanismo para gerar um grau extremamente alto de improbabilidade.
- - Natural selection is a mechanism for generating an exceedingly high degree of improbability.
- - Relatado por J. S. Huxley em Evolution in Action, Londres: Chatto e Windus, 1953.
- - Natural selection is a mechanism for generating an exceedingly high degree of improbability.
- ... foi a principal contribuição de Darwin, não apenas para a Biologia, mas para toda a ciência natural, ter trazido à luz um processo pelo qual contingências a priori improváveis recebem, no decorrer do tempo, uma probabilidade crescente, até que seja a sua não ocorrência e não a sua ocorrência, o que se torne altamente improvável. … Deixe o leitor … tentar calcular a probabilidade anterior de que cem gerações de sua ascendência na linha direta masculina deveriam ter deixado, cada um, pelo menos um filho. As probabilidades contra tal contingência, como teria parecido ao seu centésimo ancestral (mais ou menos na época do rei Salomão), exigiriam para serem expressas quarenta e quatro dígitos da notação decimal; no entanto, este evento improvável certamente aconteceu.
- - ...it was Darwin’s chief contribution, not only to Biology but to the whole of natural science, to have brought to light a process by which contingencies a priori improbable, are given, in the process of time, an increasing probability, until it is their non-occurrence rather than their occurrence which becomes highly improbable. … Let the reader … attempt to calculate the prior probability that a hundred generations of his ancestry in the direct male line should each have left at least one son. The odds against such a contingency as it would have appeared to his hundredth ancestor (about the time of King Solomon) would require for their expression forty- four figures of the decimal notation; yet this improbable event has certainly happened.
- - "Retrospect of criticisms of the theory of natural selection". Em Evolution as a Process, eds. J.S.Huxley, A.C.Hardy and E.B.Ford, Londres: Allen e Unwin, 1954.
- - ...it was Darwin’s chief contribution, not only to Biology but to the whole of natural science, to have brought to light a process by which contingencies a priori improbable, are given, in the process of time, an increasing probability, until it is their non-occurrence rather than their occurrence which becomes highly improbable. … Let the reader … attempt to calculate the prior probability that a hundred generations of his ancestry in the direct male line should each have left at least one son. The odds against such a contingency as it would have appeared to his hundredth ancestor (about the time of King Solomon) would require for their expression forty- four figures of the decimal notation; yet this improbable event has certainly happened.