STRUGGLE FOR EXISTENCE 71 



plant another, and so in other cases. We can dimlj 

 see why the competition should be most severe betweei: 

 allied forms, which fill nearly the same place in the- 

 economy of nature ; but probably in no one case could 

 we precisely say why one species has been victorious 

 over another in the great battle of life. 



A corollary of the highest importance may be de- 

 duced from the foregoing remarks, namely, that the 

 structure of every organic being is related, in the most 

 essential yet often hidden manner, to that of all other 

 organic beings, with which it comes into competition 

 for food or residence, or from which it has to escape, or 

 on which it preys. This is obvious in the structure of 

 the teeth and talons of the tiger ; and in that of the 

 legs and claws of the parasite which clings to the hair 

 on the tiger's body. But in the beautifully plumed seed 

 of the dandelion, and in the flattened and fringed legs 

 of the water-beetle, the relation seems at first confined 

 to the elements of air and water. Yet the advantage 

 of plumed seeds no doubt stands in the closest re- 

 lation to the land being already thickly clothed by other 

 plants ; so that the seeds may be widely distributed and 

 fall on unoccupied ground. In the water-beetle, the 

 structure of its legs, so well adapted for diving, allows 

 it to compete with other aquatic insects, to hunt for its 

 own prey, and to escape serving as prey to other animals. 



The store of nutriment laid up within the seeds of 

 many plants seems at first sight to have no sort of 

 relation to other plants. But from the strong growth 

 of young plants produced from such seeds (as peas 

 and beans), when sown in the midst of long grass, I 

 suspect that the chief use of the nutriment in the seed is 

 to favour the growth of the young seedling, whilst strug- 

 gling with other plants growing vigorously all around. 



Look at a plant in the midst of its range, why does 

 it not double or quadruple its numbers? We know 

 that it can perfectly well withstand a little more heat 

 or cold, dampness or dryness, for elsewhere it ranges 

 into slightly hotter or colder, damper or drier districts. 

 In this case we can clearly see that if we wished in 



