CHAPTER XXXII 



CHARACTER 

 OF OFFSPRING 



Must2im 0/ Xalural History 

 Turtle Eggs. 



Museum of Natural History 

 Dinosaur Eggs. 



What characters can be inherited f What is the relation of environ- 

 ment to heredity? Can a person consciously influence his inherit- 

 ance f What constitutes good environment f 



Variety in protoplasm. The fact that the Hving matter of all 

 plants and animals is protoplasm, has already been discussed. All 

 protoplasm is alike in certain of the elements that compose it ; it 

 is alike in its growth by assimilation, its sensitiveness to stimula- 

 tions, and its response to these stimulations. Yet protoplasm of 

 one species is different from that of another. The protoplasm 

 of a squash seed, for example, develops only into a squash vine 

 and never into a rosebush, never into a canary. The protoplasm 

 of a wren's egg develops into a wren, never into a willow tree nor 

 a Avolf. These differences are thought to be located in certain 

 parts of the chromosomes called genes. These genes are the real 

 carriers of hereditary traits. By a gene is meant the part or unit 

 factor of the chromosome, which is supposed to represent an 

 hereditary character. The development of the organism depends 

 largely upon the character-determiners of the genes. 



A many-celled organism grows by the individual cells dividing 

 mitotically. In this mitotic division, each chromosome splits into 

 two parts exactly alike. Hence, the chromosomes in all cells 



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