PRINCIPLES OF ANIMAL H1OLOGY 69 



6. Observe the following structural adaptations of animals: 



6a. The locomotor appendages of a fish; two turtles, for example, 

 Chrysemys marginata and Gophems polyphemus; three birds, for example, 

 a heron, a duck and a woodpecker; and two mammals preferably a mole 

 and a flying squirrel or a bat. 



66. The pelage of the northern form and the southern form of the 

 woodchuck. 1 



6c. The color of a forest and a desert species of horned lark. 



6d. The molar teeth of a grazing animal (bison or cow) and a browsing 

 mammal (the elk). 



60. The beaks of a duck, a woodpecker and a heron. 



List the above-mentioned forms with the environmental conditions 

 in which the structures fit them to live and the changes in conditions 

 which would probably destroy the usefulness of the structures and there- 

 fore limit the distribution of the animals. 



D. SUMMARY 



Discuss briefly the relation of diverse environmental conditions to the 

 distribution of animals. 



1 Certain other animals may be used equally well to show these regional differences. 



