PROBLEM 2. Differences Between Parents and Offspring 



465 



a 



Fig. 410 hiberitance of length of hair and coat color. The Fersiaii cat (a) and 

 Siamese cat (b) are the parents of the black, long haired daughter in (c). The light 

 colored kitten in (c) is a grandchild of the cats in (a) and (b). Which of its an- 

 cestors does it resemble? (journal of heredity) 



Fig. 411 The blosso?n of the foitr-o^ clock. Some 

 four-o'clock plants have red flowers; some, 

 white; and some, pink. How are the pink flow- 

 ers related to the others? (gehr) 



Fig. 412 The method used to preve?7t acci- 

 dental pollination iii an experi-ment with onion 

 plants. What kind of experi^tiejit might this be? 

 (u. s. department of agriculture) 



only red-flowered plants are produced. 

 If the white-flowered grandchildren are 

 crossed with each other only white- 

 flowered plants appear. But if the pink- 

 flowered grandchildren are crossed with 

 each other, the ofi"spring include plants 

 with red flowers, plants with pink 



flowers, and plants with white flowers 

 in the ratio of 1:2:1. You readily recog- 

 nize that this is the same ratio that was 

 obtained when pink-flowered plants were 

 crossed before. In order to fix these facts 

 in your mind, make the drawings sug- 

 gested in Exercise i. 



