[231]

Oct 23d

Lupinus luteus

in dark Vertical glass

[data not transcribed]

(used)

[231v]

6 (89 101

Chap. 8. Principles of Nat. Selection

shows that minor differences in fertility will be regulated by through natural selection. It is almost obvious that the fertility of each species will tends to increase, from the more fertile pairs producing a greater number of offspring, which naturally will have the best chance of surviving, and will inherit the same tendency to greater fertility. The only check to a continued augmentation of fertility of each organism seems to be either the expenditure of more more power and the greater risks run by the parents which produce a more numerous progeny, and or the contingency of very numerous eggs and young being produced of smaller size, or less vigorous, or subsequently not so well nurtured. To strike a balance in any case between their their several disadvantages from a numerous progeny, and the advantages from a large number of eggs or and young, as a means of escape from all sorts of dangers, (as favouring to escape of at least some individuals from various dangers) is quite beyond our means power of judgment in any one case.

When an organism has once been rendered extremely fertile, how its fertility can could be again reduced through natural selection is not so obvious as how this capacity was was could be first acquired. Yet it is obvious that if a species, from the decrease of its natural enemies, was habitually reared in larger numbers than could be supported, all its members would suffer. Nevertheless the

[Descent 1: 318-19: "Mr. Spencer further shews that minor differences in fertility will be regulated through natural selection. Thus the fertility of each species will tend to increase, from the more fertile pairs producing a larger number of offspring, and these from their mere number will have the best chance of surviving, and will transmit their tendency to greater fertility. The only check to a continued augmentation of fertility in each organism seems to be either the expenditure of more power and the greater risks run by the parents that produce a more numerous progeny, or the contingency of very numerous eggs and young being produced of smaller size, or less vigorous, or subsequently not so well nurtured. To strike a balance in any case between the disadvantages which follow from the production of a numerous progeny, and the advantages (such as the escape of at least some individuals from various dangers) is quite beyond our power of judgement.
When an organism has once been rendered extremely fertile, how its fertility can be reduced through natural selection is not so clear as how this capacity was first acquired. Yet it is obvious that if individuals of a species, from a decrease of their natural enemies, were habitually reared in larger numbers than could be supported, all the members would suffer. Nevertheless the offspring from the less fertile parents would have no direct advantage over the offspring from the more fertile parents, when all were mingled together in the same district."]