150 EVOLUTION OF LIFE 
know that variations appear among wild animals, and that 
these variations are transmitted to their posterity. Is there 
then also a selection in nature which brings about the same 
results as that produced by man's selection? Suppose, for 
example, a number of plants are growing in a dry place, 
it is evident that those plants whose leaves are most thickly 
haired will be favored in the struggle for water, since the 
hairs are useful in taking up moisture. These plants will 
therefore survive and reproduce their kind, while those whose 
leaves are deficient in hairs will die out. But in the next 
generation some of the plants will be characterized by still 
thicker hairs; these will therefore be preserved and pro- 
create ; but in the course of generations plants are produced 
through this Natural Selection which differ very considera- 
bly from the parent stock, not only in the hairing of the 
leaves, but in other peculiarities, as one variation sooner or 
later entails another. Thus the moisture taken up by the 
hairs furnishes a large amount of nutriment, but if the nu- 
triment is increased the flowering organs diminish ; but this 
effect in the struggle for existence will bring about other 
variations, and so on indefinitely. “The wingless condi- 
tion of so many Madeira beetles is mainly due to the action 
of natural selection, but combined probably with disuse. 
For during many successive generations, each individual 
beetle which flew least, either from its wings having been 
ever so little less perfectly developed, or from indolent habit, 
will have had the best chance of surviving from not being 
blown out to sea ; ล ท ส อ ก the other hand, those beetles which 
most readily took to flight would oftenest have been blown 
to sea, and thus have been destroyed." Through the Sur- 
vival ofthe Fittest, by Natural Selection, we see why animals 
resemble in color, etc. their surroundings or the places they 
live in. Thus, the Plant-lice and many insects are green, 
like the leaves they live upon. The Jumping Mouse, Fox, 
Lion, and Gazelle are yellow or yellowish-brown, like the 
