Darwin believed that the crossing of two types generally led to a blend, and that consequently bisexual reproduction tended to make a species uniform. He therefore had to postulate some cause constantly at work to keep up the inheritable variation within a species. He very naturally looked to the effects of differences of environment. ...It was shown that Darwin had been wrong in supposing that variations due to environment were inheritable. Selection merely picked out the best available line from a given population, and would not, as Darwin had believed, give rise to an unlimited amount of change.
J. B. S. HaldaneRelated topics
best bisexual cause change crossing due given led line postulate reproduction rise selection show variation work wrong darwinRelated quotes
Animal behavior has evolved to battle parasites. In fact, we have parasites to thank for the existence of sex. Sex is a costly and time-consuming method of reproduction. Experiments have shown that, in the absence of parasites, species evolve toward parthenogenesis-or cloning-as the reproductive method of choice. In parthenogenesis each individual is able to self-replicate. But this produces almost no genetic variation. In the presence of parasites, cloning, while more energy-efficient, is not a viable reproductive strategy. It presents a stationary genetic target to parasites, who, once introduced into such a system, will quickly dominate it. ...
Daniel Suarez
When blimp photographs are taken of giant stadia packed full of rock-concert or football fans, we get an idea of what 100,000 people look like. We all think of Hiroshima as the worst single killing of humans by humans. That was about a 75,000-capacity-coliseum-full. Each day of each year, year after year, a 75,000-capacity-stadiumfull of around-the-world humans perish from starvation or its side effects, despite an annual average 5-percent world food-production overage of the amount of food adequate for the total world's population. This daily kill of innocents dwarfs the awful Auschwitz killing.
Buckminster Fuller
The giraffe's neck supposedly supplies a crucial example for preferring natural selection over Lamarckism as a cause of evolution. But Darwin himself (however wrongly by later judgement) did not deny the Lamarckian principle of inheritance for characters acquired by use or lost by disuse. He regarded the Lamarckian mechanism as weak, infrequent, and entirely subsidiary to natural selection, but he accepted the validity of evolution by use and disuse. Darwin does speculate about the adaptive advantage of giraffe's necks, but he cites both natural selection and Lamarckism as probable causes of elongation.
Stephen Jay Gould
THE thousand injuries of Fortunato I had borne as I best could, but when he ventured upon insult I vowed revenge. You, who so well know the nature of my soul, will not suppose, however, that gave utterance to a threat. At length I would be avenged; this was a point definitely, settled --but the very definitiveness with which it was resolved precluded the idea of risk. I must not only punish but punish with impunity. A wrong is unredressed when retribution overtakes its redresser. It is equally unredressed when the avenger fails to make himself felt as such to him who has done the wrong.
Edgar Allan Poe
Reading is merely a surrogate for thinking for yourself; it means letting someone else direct your thoughts. Many books, moreover, serve merely to show how many ways there are of being wrong, and how far astray you yourself would go if you followed their guidance. You should read only when your own thoughts dry up, which will of course happen frequently enough even to the best heads; but to banish your own thoughts so as to take up a book is a sin against the holy ghost; it is like deserting untrammeled nature to look at a herbarium or engravings of landscapes.
Arthur Schopenhauer