62 BIOLOGY AND HUMAN LIFE 



50. Protoplasm fundamentaL Protoplasm has been called the 

 physical basis of life ; it is well named the first, or basic, mate- 

 rial. As we have seen, in the one-celled ameba (and in other 

 one-celled animals, as well as in one-celled plants) the single bit 

 of protoplasm carries on all the life activities — growth, movement, 

 reproduction, etc. Yet in the larger plants and animals (those 

 having several kinds of cells and millions of each kind) the pro- 

 toplasm of every cell carries on the same fundamental activities. 

 However different a bone cell may be from a brain cell, for ex- 

 ample, or a root-hair cell from a blood cell, the protoplasm in all 

 cases is irritable, it is capable of growth, it shows some movement, 

 and at least at some stage in its life it is capable of reproduction. 



The many kinds of organisms, with peculiar forms and organs, 

 and the many different kinds of activities that are a constant 

 source of wonder arise apparently from the fact that proto- 

 plasm, always the same in some respects, is yet always capable 

 of changing its manner of living as circumstances change. Funda- 

 mentally always the same, in every particular case it is distinct 

 or peculiar ; this is characteristic of protoplasm, as it is char- 

 acteristic of life. 



LIVING MATTER 



1. Protoplasm 



Appearance Qualities 



Structure Irritability 



Importance Assimilation 



Movement 



2. Cells 



Where found Kinds 

 Structure One-celled plants 



Plasma One-celled animals 



Nucleus Plant tissues 



Wall Animal tissues 



3. Cell division 



Stages in cell division 



Cell division in one- Cell division in many- 

 celled plants celled organisms 



Cell division in one- Relation to growth 



celled animals Relation to reproduction 



