American Museum of Natural History 



CONVERGENCE OF DIVERSE FORMS 



Marsupials living almost exclusively in Australia and near-by islands resemble in 

 outward appearance various placental mammals living in other parts of the world. 

 How came the koala and the bear to be so much alike? One series of species appears 

 to be as well adapted as the other 



A different kind of restriction is illustrated by the fact that clover and 

 alfalfa can grow only where there is an abundance of lime in the soil, whereas 

 blueberries and cranberries, which belong to the heath family, thrive on acid 

 soil. Most seed plants depend upon nitrogen compounds in the soil. Members 

 of the bean family, however, can get along on soils deficient in nitrogen; but 



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