Alternative Theories 



It will be observed that we have quoted very 

 largely from Professor Poulton's work. Our 

 reason for so doing is that he appears to be the 

 most prominent advocate of the theory of protec- 

 tive mimicry, and his work, which was published 

 in 1908, may be taken as the latest Neo-Dar- 

 winian pronouncement on the subject. 



Hence if we can show, as we believe we can, 

 that his arguments are not sound, we may take 

 it that we have demonstrated that the theory in 

 its present form is untenable. 



It is worthy of notice that Professor Poulton 

 sets forth three other suggestions which have 

 been proposed as substitutes for natural selec- 

 tion as an explanation of the phenomena of 

 mimicry. 



The first is the theory of External Causes, 

 namely, that the resemblance is due to some 

 external cause, such as food or climate. 



The second is the theory of Internal Causes, 

 which states that mimetic resemblance is due to 

 internal developmental causes. 



The third is the suggestion that sexual 

 selection has caused the origin of these re- 

 semblances. 



He then proceeds to demolish these to his 

 own satisfaction, and adds triumphantly, " The 

 conclusion appears inevitable that under no 

 theory, except natural selection, do the various 

 resemblances of animals to their organic and 



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