WHAT EVOLUTION IS 8i 



claimed natural selection as the all- 

 sufficient factor in evolution. 



The objections that were raised 

 against Lamarckism by its opponents 

 were first of all as to its limitations. 

 As a process effective in evolution it 

 applies to those changes that are in- 

 duced either directly by the environ- 

 ment or indirectly through exercise, 

 lack of exercise, and the like. 



Some conditions seen in organisms 

 do not easily fall under any of these 

 heads. The protective coloration of 

 insects is an example of this kind. 

 Many insects exhibit colors, forms, 

 and activities that make them easily 

 mistaken for other objects in their 

 environment. Moths resemble the 

 bark of the trees on which they rest, 

 butterflies, on closing their wings, be- 

 come indistinguishable from leaves 

 or the earth and the walking-stick 

 insect gets its name from its resem- 



