PART n. LIFE PROCESSES IN LIVING THINGS. 

 GREEN PLANTS AS LIVING ORGANISMS 



CHAPTER V 



THE BUILDING MATERIAL OF LIVING THINGS 



Problems : To study cells in both plants and animals and find, 

 the ways in which they are alike and different. 

 To study the parts of a typical cell. 

 To learn how cells produce other cells. 



Laboeatory Suggestions. 



Examination of cells from inside of cheek. 

 Examination of cells from onion epidermis. 

 Demonstration of elodea and protoplasmic movement. 

 Demonstration of stained sea urchin or starfish egg to show chromosomes. 

 Demonstration of dividing sea urchin or other eggs to show phases of 

 cell division. 



Many Forms of Plants and Animals. — It is common knowledge 

 that many kinds of green plants have roots, a stem, and leaves 

 and bear at some time flowers, which give rise to fruits containing 

 seeds. If a seed is planted, we know it will grow into a young 

 plant of the same kind as produced it. But there are plants which 

 do not form seeds, such as the mosses and ferns, and there are still 

 others that are not green in color and may be too small to see with 

 the unaided eye. 



Animals, too, as we know, are very diverse in size and appear- 

 ance. A visit to a '' zoo " or a museum gives us some idea of the 

 multitude of forms and their varied places of habitat. Insects, 

 of which we know a little, are very numerous and very different 

 from one another. And in animal life, as well as among the 

 plants, we find forms so minute that we have to call the com- 

 pound microscope to our aid in order to see them. 



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