3o6 



Why Living Things Behave As They Do unit v 



Fic;. 2S4 Two views of a Vemis''s-flytrap leaf. When an insect touches the short hairs 

 on this leaf, the leaf quickly folds up as though it were hifio^ed in the middle. Thus 

 the insect is trapped. Juices are then secreted and the insect is slowly digested and 

 gradually absorbed. The "insect-eating'" plants, like animals, can use meat as part of 

 their food. They do not depend upoii this source, however, (hugh spencer) 



Fig. 2H5 Sundew. 'The whole plant at left and a close-up of one of the leaves at right. 

 Perhaps at soine time you have found these striidew plants in a bog or at a botanical 

 garden greenhouse. Do you see that the leaves are covered with tiny hairs, each with a 

 drop of liquid at its tip? The photograph cannot show how these drops of sticky 

 liqiiid glisten in the sunlight. Insects attracted to these leaves alight on theni and are 

 caught by the sticky substance. The tiny hairs soon respond by folding dowj? over the 

 prey, ef?tanglij7g it. Digestive juices are then secreted by the leaf, and after a tinie the 

 ivsect is digested and absorbed, (hugh spencer) 



