HOW PLANTS CAME TO DIFFEK. 31 



two great principles. The Struggle for Life 

 means that more creatures are produced than 

 there is room in the world for. Natural Selec- 

 tion (or Survival of the Fittest) means that among 

 them all, those which happen to be best adapted 

 to their particular circumstances oftenest suc- 

 ceed and leave most offspring. 



By the action of the two great principles in 

 question (which affect all life, animal or vege- 

 table) the world has been gradually filled with 

 an immense variety of wonderful and beautiful 

 creatures, all ultimately descended (as modern 

 thinkers hold) from the selfsame ancestors. 

 The simple little green jelly-speck, which is the 

 primitive plant, has given rise " in time to the 

 sea- weeds and liverworts, then to the mosses 

 and ferns, then to the simplest flowering plants, 

 thence to the shrubs and trees, and finally to 

 all the immense wealth and variety of fruits, 

 flowers, and foliage we now see around us. 



The rest of this book will consist mainly of an 

 exposition of the results brought about among 

 plants by Variation, the Struggle for Life, and 

 Survival of the Fittest. But before we go on to 

 examine them in detail, I shall give just a few 

 characteristic instances which show the mode of 

 action of these important principles. 



There is a pretty wild flower in our hedges 

 called a red campion, or " Eobin Hood/' Now, 

 a single red campion produces in a year three 

 thousand seeds. But there are not three thou- 

 sand times as many red campions this year as 

 last, nor will there be three thousand times as 



