Source: The Causes of Evolution (1932), Ch. IV Natural Selection, p. 102.
Quotes from book
The Causes of Evolution
The Causes of Evolution is a 1932 book on evolution by J.B.S. Haldane , based on a series of January 1931 lectures entitled "A Re-examination of Darwinism". It was influential in the founding of population genetics and the modern synthesis.
Introduction, pp.20-21.
The Causes of Evolution (1932)
Source: The Causes of Evolution (1932), Ch. IV Natural Selection, p. 104.
Introduction, pp.14-20.
The Causes of Evolution (1932)
Introduction, pp. 3-4.
The Causes of Evolution (1932)
Introduction, p. 22.
The Causes of Evolution (1932)
Introduction, p. 2.
The Causes of Evolution (1932)
Source: The Causes of Evolution (1932), Ch. IV Natural Selection, pp. 103-104.
“Our ancestors were mostly rather rare creatures.”
Appendix, pp. 213-214.
The Causes of Evolution (1932)
Context: Wright's theory certainly supports the view taken in this book that the evolution in large random-mating populations, which is recorded by palaeontology, is not representative of evolution in general, and perhaps gives a false impression of the events occurring in less numerous species. It is a striking fact that none of the extinct species, which, from the abundance of their fossil remains, are well known to us, appear to have been in our own ancestral line. Our ancestors were mostly rather rare creatures. " Blessed are the meek : for they shall inherit the earth."
Appendix
The Causes of Evolution (1932)
Context: Unaided common sense may indicate an equilibrium, but rarely, if ever, tells us whether it is stable. If much of the investigation here summarised has only proved the obvious, the obvious is worth proving when this can be done. And if the relative importance of selection and mutation is obvious, it has certainly not always been recognised as such.
Source: The Causes of Evolution (1932), Ch. V What is Fitness?, p. 150.
“Another possible mode of making rapid evolutionary jumps is by hybridisation.”
Source: The Causes of Evolution (1932), Ch. IV Natural Selection, pp. 104-106.
Context: Where natural selection slackens, new forms may arise which would not survive under more rigid competition, and many ultimately hardy combinations will thus have a chance of arising.... Thus the distinction between the principal mammalian orders seems to have arisen during an orgy of variation in the early Eocene which followed the doom of the great reptiles... Since that date mammalian evolution has been a slower affair, largely a progressive improvement of the types originally laid down in the Eocene.
Another possible mode of making rapid evolutionary jumps is by hybridisation.... hybridisation (where the hybrids are fertile) usually causes an epidemic of variation in the second generation which may include new and valuable types which could not have arisen within a species by slower evolution.
Source: The Causes of Evolution (1932), Ch. IV Natural Selection, pp. 104-106.
Context: Where natural selection slackens, new forms may arise which would not survive under more rigid competition, and many ultimately hardy combinations will thus have a chance of arising.... Thus the distinction between the principal mammalian orders seems to have arisen during an orgy of variation in the early Eocene which followed the doom of the great reptiles... Since that date mammalian evolution has been a slower affair, largely a progressive improvement of the types originally laid down in the Eocene.
Another possible mode of making rapid evolutionary jumps is by hybridisation.... hybridisation (where the hybrids are fertile) usually causes an epidemic of variation in the second generation which may include new and valuable types which could not have arisen within a species by slower evolution.
Source: The Causes of Evolution (1932), Ch. V What is Fitness?, pp. 158-159.
Context: I have given my reasons for thinking that we can probably explain evolution in terms of the capacity for variation of individual organisms, and the selection exercised on them by their environment....
The most obvious alternative to this view is to hold that evolution has throughout been guided by divine power. There are two objections to this hypothesis. Most lines of descent end in extinction, and commonly the end is reached by a number of different lines evolving in parallel. This does not suggest the work of an intelligent designer, still less of an all mighty one. But the moral objection is perhaps more serious. A very large number of originally free-living Crustacea, worms, and so on, have evolved into parasites. In doing so they have lost, to a greater or less extent, their legs, eyes, and brains, and have become in many cases the course of considerable and prolonged pain to other animals and to man. If we are going to take an ethical point of view at all (and we must do so when discussing theological questions), we are, I think, bound to place this loss of faculties coupled with increased infliction of suffering in the same class as moral breakdown in a human being, which can often be traced to genetical causes. To put the matter in a more concrete way, Blake expressed some doubt as to whether God had made the tiger. But the tiger is in many ways an admirable animal. We have now to ask whether God made the tapeworm. And it is questionable whether an affirmative answer fits in either with what we know about the process of evolution or what many of us believe about the moral perfection of God.
Introduction, p. 9.
The Causes of Evolution (1932)
Context: Comparative parasitology supports the evolutionary hypothesis. If two animals have a common ancestor, their parasites are likely to be descended from those of the ancestor. This principle has been applied with considerable effect to the classification of frogs and other groups.
