How Do the Conflicts of Animals Differ from Those of Plants? 



Intensification of Life' Since all living things carry on essentially the 

 same fundamental processes, animals are, so to say, just like plants — only 

 more so. But that is not quite true, nor all the truth. For plants in general are 

 much more effective food-makers and food -assimila tors. A pound of plant 

 protoplasm can become two pounds more quickly than can a pound of animal 

 protoplasm, adequate supplies being assumed, of course, in both cases. And 

 plants can take a great deal more punishment without gi^■ing up. But perhaps 

 that is only another way of saying that by means of growth they can more 

 easily make up the injuries they sustain. 



This suggests, however, more far-reaching differences. If most animals 

 cannot take so much abuse, they do not have to take it — for they are motile 

 and can get away or hit back. Or they can sense danger at a distance and dis- 

 appear before trouble reaches them. Most animals are able to carry on — to 

 struggle — in ways that plants generally cannot match. 



The rate of metabolism in animals is generally higher. That means that for 

 each unit of protoplasm they use up more food in a given time. But since 

 animals are not food-makers, they spend relatively more time and energy in 

 foraging. These facts suggest differences in the intensity of living, although 

 many animals are fixed in their positions like plants, and others are very slug- 

 gish in their movements. 



Sensitiveness Animals seem generally much more sensitive than plants, 

 although a passing cloud will change the rate of photosynthesis and of res- 

 piration in a plant. If we survey the various types, from the simplest to 

 the more complex, we see more and more specialized sense organs. From the 

 eyespot of the euglena we go to the complex eyes of \ertebrates and the 

 cephalopod mollusk — the octopus, for example. From sensiti\'eness to me- 

 chanical disturbance in the ameba and sensitive hairs in the coelenterates 

 (hydra, sea-anemones) we go to the antennae of insects and crustaceans and 

 the ears of vertebrates. From the chemical sense of the paramecium we go 

 to the fine sense of smell in many mammals. Animals seem to extend their 

 contacts with the world, to enlarge the range of the environment to which 

 they relate themselves — and fit themselves. Thus an animal can discover 

 enemies or food at a distance, and act accordingly. 



In the case of human beings the sense organs and their connections have 

 made the task of obtaining food and escaping enemies both more complex and 

 easier. The sense organs are "receptors", or receivers of impressions, signals, 

 information, and so on (see page 275). They make the tasks of life easier, for 

 they enable the organism to draw upon greater resources. But they make life 

 more complex too. For they compel the organism to take note of a greater 



iSee No. 5, p. 558. 

 551 



