No. 643] 



EFFECTS OF ENVIRONMENT 



145 



particular internal pattern that consists of a graded 

 series of metabolic activities which {de Child) is a direct 

 response to stimuli received from the environment. 



In responding to environment plants and animals show 

 fundamental similarity. Many plants adjust themselves 

 to their surroundings by assuming the form that best 

 suits them to the particular space in which they happen 

 to take up a sessile life, and many animals secure a place 

 which is suited to their system of activities by moving 

 about until they find it. This difference between plants 

 and animals is largely due to the fact that the former 

 usually are able to subsist on inorganic foods, wiiile the 

 latter require organic substances as a basis for their 

 metabolic activities. However, animals often respond to 

 the environment by assuming a particular growth form, 

 and plants have many motile systems of activities that 

 find favorable environments through active or passive 

 migrations. Being trained as a zoologist and knowing 

 little of the activities of plants, I gladly take the task as- 

 signed to me— "to discuss the effects of environment on 

 animals" — but I can not refrain from expressing my 

 opinion, that there is no essential distinction in this con- 

 nection between the two great kingdoms of life. 



Animals are continually active and must continually re- 

 act with the environment. Alcock* said, ' ' the three great 

 exigencies: to find something to eat, to avoid being one's 

 self eaten, and to disseminate one's species, give rise to a 

 perpetual struggle in which the fittest are successful." 

 The environment furnishes matter and energy to main- 

 tain the activities of each system and a considerable quan- 

 tity of both is neccessary. A silkworm during its short 

 life eats food amounting to 86,000 times its own weight at 

 the time of hatching. Animals take the most diverse mate- 

 ials from the environment and use them to build substance 

 or furnish energj^ The clothes moth flourishes on a diet 

 of wool, which consists entirely of keratin. From this 

 almost pure, and to most animals wholly indigestible, pro- 



* " A Naturalist in Indian Seas. ' ' London, 1902. 



