CHAPTER VI 



COMPARISON OF ANIMAL AND PLANT BIOLOGY 



IN an earlier lesson ( 29) we noticed that living animals 

 and plants have certain characteristics which lifeless things 

 do not have. Most evident of these characteristics are move- 

 ment, taking food and assimilating it, breathing, reproducing. 

 We have now studied these and other activities more carefully, 

 and are ready to compare the animal and the plant. With- 

 out careful study, a frog and a bean plant seem to have 

 nothing in common, except that they are both living; but 

 a detailed study has 



shown us the follow- 

 ing remarkable simi- 

 larity between the 

 animal and the plant. 

 111. Similarity of 

 Structure of Bodies of 

 Animals and Plants. 

 In both the frog and 

 the bean the essential 

 living substance is 

 protoplasm, and this 

 is found in units of 

 structure called cells 

 (see Figs. 40, 41). 

 Chemical analysis has 

 shown no essential difference between animal and plant pro- 

 toplasm. Both animal and plant cells have nuclei, and they 

 multiply by an automatic process of division. Biologists 



122 



FIG. 40. Epidermis of salamander tadpole. 

 Three cells undergoing division. (From 

 Wilson.) 



