XIV. DIVISION OF LABOR. THE VARIOUS FORMS OF 

 PLANTS AND ANIMALS 



Problems. — The development and forms of plants. 



The development of a simple animal. 



What is division of labor ? In what does it result ? 



How to hnaw the chief characters of some great animal 



groups. 



Laboeatort Suggestions 



A visit to a botanical garden or laboratory demonstration. — Some of the 

 forms of plant life. Review of essential facts in development of bean or 

 corn embryo. 



Demonstration. — Charts or models showing the development of a many- 

 ceUed animal from egg through gastrula stage. 



Demonstration. — Types which illustrate increasing complexity of body 

 form and division of labor. 



Museum trip. — To afford pupil a means of identification of examples 

 of principal phyla. This should be preceded by objective demonstration 

 work in school laboratory. 



To THE Teacher. — The object of this chapter is to give the pupil a bird's-eye 

 view of the plant and animal kingdoms. This is not done for the sake of accurate 

 classification, but simply to impress him with the wonderful diversity and com- 

 plexity of form and structure in the living world about him. Also these exercises 

 should bring home the idea that division of labor and complexity of structure in 

 plants and animals go hand in hand. The exercise in determining the place of 

 animals and plants in the evolutionary scale should be largely an exercise in deter- 

 mining the amount of division of labor shown in a given group. It is needless to 

 say that the work can best be done by means of type collections in a museum or in 

 the laboratory. The outline (Problem 118) in the hands of the pupils aids in the 

 identification of the various phyla. Comparison of type forms under these phyla 

 gives the pupil an excellent opportunity for study of relation of forms. 



Problem 114: : How the plant kingdom is classified. 

 Materials. — Specimens of algse, fungi, mosses, ferns, and 

 flowering plants. 



Note. — ah animal and plant Ufe shows greater or less division of labor, the 

 more complex forms showing greater division of labor. We classify as higher the 

 plants or animals showing greater division of labor. 



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