42 EVOLUTION. 



7. Animals and plants have rudiments of organs, 

 which are useless and in some cases disappear in 

 adult life. This can only be explained by the sup- 

 position that these forms are inherited from ancestors 

 who possessed them fully developed. 



8. Change of surroundings causes change in the 

 organs of animals, in consequence of the survival of 

 those who possess any peculiarity that makes them 

 better fitted to endure the changes, and these peculi- 

 arities become fixed in their descendants. 



9. These changes of surroundings sometimes lead 

 animals to revert to the forms of lower organisms, 

 making it probable that their race formerly arose 

 from those forms through the influence of changed 

 conditions, which ceasing, the new forms are no longer 

 useful and disappear. 



10. The mimicry by animals of resemblances that 

 are useful shows that new species may arise by the 

 perpetuation of useful variations of form or color. 



11. The distribution of animals and plants over 

 the earth shows that natural causes account for the 

 presence of each kind in its locality. 



12. The study of fossil remains of plants and 

 animals reveals links between orders so separate that 

 they have been regarded as special creations. But 

 these intermediate forms show the transition from 

 one species to another. 



13. In the oldest rocks the lowest forms of life are 

 found, and higher forms appear successively in later 



