5 1 8 Organisms Are Products of Heredity and Eyivironment unit ix 



2. Study the pedigree illustrating shortsightedness. Using the letters 7i 

 (normal) and 5" (shortsighted) illustrate this pedigree by using letters in- 

 stead of squares and circles. 



3. Can you find out about any unusual character (no matter how 

 small) in your family, or in that of some friend's family? Obtain all the 

 information you can and construct a chart. Be sure to state fully the 

 sources of your information; your classmates will want to know how^ 

 reliable your facts are. 



4. Careful study of the pedigree illustrating the inheritance of an ab- 

 normal skin condition will show whether the character is caused by a 

 recessive or dominant gene. Explain the genetic make-up of each indi- 

 vidual that shows the defect. 



5. Discuss with your family the possibility of arriving at a decision as 

 to which genes are desirable and which undesirable. In general, do the 

 most intelligent people earn most? Write down your thoughts in an or- 

 derly way and discuss them with your classmates. 



6. Prepare a short list of occupations, including such work as coal 

 mining, nursing, teaching, and waiting on table. For each type of work 

 name the part of the body that may be affected or injured. Discuss this 

 with adults and with your classmates. 



7. Can you explain why identical twins are likely to vary less in fea- 

 tures than in weight? Explain in what respects the environment of twins 

 brought up in the same family and going to the same school might be 

 different. 



8. From your own experience and by reading reliable articles on iden- 

 tical twins (such as in the Journal of Heredity) prepare a report to the 

 class. There are books on the subject that you can consult. 



9. Look through the files of newspapers carefully for news items on 

 heredity in twins or related topics. Bring the information to class and 

 discuss it. How much of what you read can you believe? Which tend to 

 be more reliable, these news items on twins or those on such a subject as 

 "changes in the earth"? Explain. 



10. Find out what your state laws on the subject of child labor are. 

 Find out which states have failed to ratify the child labor amendment. 



11. Add to the list of w^ays in which man has improved his environ- 

 ment within the last century. In which respects is his environment not as 

 good? What else might be done to improve your environment? 



12. Make as long a list of superstitions as you can. Discuss these with 

 the class. Try to determine how each arose. Show how science has freed 

 man from unnecessary fears. 



Further Activities in Biology 



I. You may be interested in reading about the Kallikaks in more detail 

 (Goddard's KaUikak Faujily). You will also read how the feeble-minded 

 are trained. 



