Preservation of the Species 149 



distinguishable, until we approached close enough to startle 

 it. Many an idle rambler has reached for a leaf or twig only 

 to have it fly away from under the hand. The flatfish is in- 

 distinguishable in the water when resting on the bottom. 

 Insects match the leaves and bark of the plants upon which 

 they rest in a manner that must at least in many cases serve 

 to protect them from possible enemies. The practice of 

 camouflage during the World War was developed entirely 

 from observations made upon the protective colorations and 

 patterns of living things. It is true that many of the color- 

 ings found in plants and animals are incidental to the chemi- 

 cal constitution of their food and to the chemical processes 

 that go on within their bodies. It is true also that there are 

 many colors that can have no conceivable connection with 

 advantage to their bearers. Yet there remains a substantial 

 body of truth in the assumption that color, as well as form, 

 may often have adaptive significance in the life of many 

 plants and animals. 



Preservation of the Species 



Adaptations to reproduction include a wide range of 

 structures and processes that have always fascinated the stu- 

 dent of nature. Many water plants and animals discharge 

 their eggs and sperms into the water where fertilization is 

 largely a matter of chance meeting of two germ cells. Mil- 

 lions are called but few are chosen. In other cases, there is an 

 increased probability of mating through special structures or 

 special modes of movement, or through responsiveness to 

 special stimuli. The adaptation of flowers to the visits of 

 birds and insects and the complementary instincts of the 

 insects and birds, which bring about cross pollination for 

 the flowers while supplying food to the visitors, have im- 

 pressed the thoughtful as truly remarkable. The details of 

 structure and markings in some of the orchids and their re- 

 lation to particular species of visiting bees or butterflies are 

 most exquisite. 



