490 BIOLOGY AND HUMAN LIFE 



Reptiles 



Hatching outside the body 

 Birds 



Hatching outside the body but with parent's heat 

 Feeding after hatching 

 Mammals 



Hatching inside the body 



Feeding from mother's body after birth 

 4. Importance of prolonged infancy 



QUESTIONS 



1. What advantages have water animals over those that live on land 

 or in the air ? What disadvantages have they ? 



2. Of what advantage to a species is the production of very large num- 

 bers of spores or eggs ? Of what disadvantage is it ? 



3. What are the advantages of asexual reproduction over sexual? 

 What are the disadvantages ? 



4. What are the advantages that birds get from building nests for 

 their young ? What are the disadvantages ? 



5. What are the advantages of having the young able to take care of 



themselves early? What are the disadvantages? 



• 



6. What can be done to prevent the waste of millions of fish eggs ? 



7. How- can we control the multiplication of useful animals ? 



8. How can we control the multiplication of harmful animals ? 



REFERENCE READINGS 



Bureau of Fisheries. Economic Circular jg, Artificial Propagation of 

 Carp. 



Bureau of Fisheries. Annual Report, 1919, Appendix 2, Artificial Propa- 

 gation of Salmons of the Pacific Coast. 



Farmers' Biilletifi 1040, Illustrated Poultry Primer. 



Partners' Bulletin 542, Organization of Poultry Clubs. 



Robinson, J. H. Domestic Birds, pp. 16-23. 



