SUBJECTIVE LESSONS.* 



Factors of Evolution (Chapter II, pages 14-16). — Give 

 examples illustrating the diversity shown in the structure 

 and habits of birds. What theory has been advanced to 

 account for the wide variation in structure shown by birds ? 

 What is meant by Natural Selection ? How does the 

 theory of Lamarck differ from that of Darwin ? How 

 may the tail-featliers of the Woodpecker have acquired 

 their present pointed shape ? Is it probable that the Wood- 

 l^ecker's barbed tongue has been acquired in the same 

 manner ? 



Form and Habit. 



The Wing (Chapter II, pages 17-24).— Name the func- 

 tions of the wing. What is doubtless its most primitive 

 use as an organ of locomotion ? How is it used by young 

 Gallinules ? By the young Hoatzin ? How is it used by 

 Grebes and Penguins ? By the Ostricli ? What variation 

 in expanse of wings is presented by birds ? What rela- 

 tion exists between shape of wing and style of flight ? 

 Give illustrations. Mention some flightless birds. Why 

 is flight necessary to the Razor-billed Auk ? Under what 

 conditions might it exist without the power of flight ? 

 What group of flightless birds is found in the Antarctic 

 region ? Where do they nest ? Why ? What birds be- 

 come temporarily flightless ? In what manner ? What 

 lake is inhabited by a flightless Grebe ? Where are flight- 

 less Gallinules found ? How did they probably reach the 

 islands they now inhabit ? Mention other flightless birds. 



* The value of these lessons will be great ly enhanced if the 

 teacher will constantly have the pupil name additional species in 

 illustration of the facts and theories here mentioned. 



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