[134]

Review on The Descent of Man

 

At page 297 the following words are found.

[134v]

"and we may conclude then that the successive variations, by which the adult male became modified cannot have occurred much before the age of reproduction

"How then are we to account for this coincidence between the periods of variability and that of sexual selection" Mr D. then states that the reason is that the variations "occurring at a later age have been preserved"

[135]

and explains this in the next paragraph. He states that variations occurring in youth, for instance in brightness, and which immediately were not of the least service to the animal, would run a risk good chance of being utterly lost" owing to the great mortality of youth.

Let us take an example, as he has done, — suppose a family of 25 of which 19

[135v]

died before maturity Now of the remaining 6 3 would be more beautiful and 3 less so, the former producing more offspring that the other. But it would not signify whether the 3 more beautiful became so at a late age or at an early one, hence it seems that Mr Darwin's idea of the chance of variations in youth

[136]

Thus we see that the period before reproduction may be roughly divided into two periods one in which the variations are transported to both sexes and the other in which this is not the case. In the first of these periods variations in beauty will occur in the male and be sexually selected when they come to maturity, thus

[137]

giving certain characters wh to the males, females and young, which might almost be called sexual. In the second period the females will remain unchanged, as any variations which occurred will be destroyed through intercrossing, because there is not any selection at work But with the males these variations will be selected and the male will thus

[138]

being destroyed be more than the variations occurring at an old age is a fallacy. It is based on the assumption of the mortality of youth; but with regard to this quality of brightness, which is here supposed not to effect the mortality of youth, we may suppose that the 6 left are typical and their mortality in youth is nil, hence the assumption falls to the ground.

[138v]

assumption falls to the ground.