INTRODUCTORY PROBLEMS 9 



Just as in human affairs we are always thinking of people, 

 place, and work, so in biology we are always thinking of 

 organisms, environment, and function. 



Sometimes it seems to us as if the living creatures were thralls 

 in the grip of a tyrannous environment, and we use the words in 

 the order environment, function, organisms. At other times, 

 particularly among the animals with better brains, it seems to 

 us as if the living creatures were to a remarkable degree masters of 

 their fate, selecting their environment, using it, modifying it. We 

 then use the words in the order organisms, function, environment. 



The circular diagram suggests an analysis of the surroundings 

 of an animal into successive spheres of influence (I.) Mechanical, 

 such as pressures, gravity, currents, etc.; (II.) Chemical, such as the 

 nature of the food and drink, the salinity of the water, the com- 

 position of the soil ; (III.) Physical, such as the conditions of heat, 

 light, and electricity ; and (IV.) Animate, the direct influence of 

 neighbours, fellows, messmates, parasites, etc. 



It need hardly be pointed out that there are relations between 

 a living creature and its surroundings which are normal and 

 usual, and that changes in these relations may be followed by 

 temporary or permanent, individual or racial adjustment on the 

 part of the organism, including, of course, any device by which 

 the organism evades the change altogether. In other cases the 

 relation between an animal and its surroundings is too subtle to 

 admit of more than a slight change. More than that is fatal. 



SECTION 3. THE BEHAVIOUR OF ANIMALS. In spring and 

 summer the school nature study should include much observation 

 as far as possible in the open air of the works and ways of 

 animals, such as ants, bees, wasps, spiders, earthworms, snails, birds. 

 Their behaviour may be conveniently studied under the heads : 



Seeking for food, preparing it, storing it. 



Making shelters, hiding-places, homes. 



Adjusting themselves to their inanimate surroundings, e.g. 



in migration, concealment, change of colour. 

 Adjusting themselves to other creatures, e.g. in combat. 

 Finding mates, and it may be " courting " them. 

 Preparing for, feeding, protecting, even teaching their young. 



