524 



BIOLOGY AND HUMAN LIFE 



HEREDITY IN ANIMALS 



Name of Animal 



Cattle 



Horse 



Silkworm .... 



Rabbits "1 

 Guinea pigj 

 Mice ...... 



Mice "I 



Rabbits I' • • • 

 Guinea pigj 

 Leghorn poultry 

 Salamander . . . 



Canary 



Poultry 



Poultry 



Land snail .... 

 Pomace flies . . . 



Dominant Character 



Hornlessness 

 Trotting 

 Yellow cocoon 



Short fur 



Normal movements 



Pigmented coat 



White plumage 

 Dark color 

 Crested head 

 Rose comb 

 Short rump 

 Plain shell 

 Red eves 



Recessive Character 



Horns 

 Pacing 

 White cocoon 



Angora fur 

 Waltzing habit 



White coat 



Pigmented plumage 

 Light color 

 Plain head 

 Single comb 

 Long tail 

 Banded shell 

 White eyes 



In raising sheep certain kinds of fleece are found to be more 

 profitable than others. In order to combine such a desirable 

 quality with some others, it would be necessary first to find out 

 which characters were dominant and which recessive, then 

 hybrids would be produced and inbred until the segregation 

 appeared in the third generation. Next, individuals having 

 desirable combinations of characters would be picked out 

 for further multiplication. 



381. The law of combination. The law of unit characters, 

 which makes possible the establishment of individuals with new 

 combinations of characters, applies to animals, as do the other 

 Mendelian principles. In the guinea pig, for example, we can 

 combine long hair from one parent with white coat from an- 

 other, or short hair from one parent with blackness from another 

 (see Fig. 219). Many of the breeds of cattle raised on the large 

 prairie ranches of the Middle West have excellent beef qualities 

 and are easily handled in large herds, but most of them are sus- 

 ceptible to the destructive Texas fever, which has caused the 



