Our Balanced World 545 



Some forms of animal life, notably mosquitoes, flies, and rats, 

 are especially harmful to man because they are carriers of disease 

 germs. Every possible effort should be made to do away with 

 these pests. 



FACT AND THOUGHT QUESTIONS 



1. Explain how a balanced aquarium illustrates the mutual aid of animals 

 and plants. 



2. Describe the carbon-oxygen cycle. 



3. Describe the nitrogen cycle. 



4. What may happen in a locality if there is not enough plant life for 

 the animal life? 



5. How do bees and flowers afford mutual aid? 



6. Discuss the beneficial relations of birds to man. 



7. What might happen if all birds were driven away? 



8. Is it always advisable to drive away birds that eat some of our berries 

 or fruit? 



9. Discuss the relation of the rat to man. 



10. Discuss the relation of the mosquito to the health of man. 



11. Discuss the relation of the house fly to the health of man. 



12. How does a thorough clean-up of the home yard aid our fight against 

 animal carriers of disease? 



PROJECTS 



1. Make a balanced aquarium. 



2. Make a balanced terrarium. 



OUTDOOR OBSERVATION 



1. Observe and list forms of animal life in your general neighborhood 

 that are injurious to man. 



2. Observe the birds in your neighborhood, noting so far as possible 

 what they eat. Record your findings. 



3. Observe and report on conditions in your neighborhood which favor 

 the breeding of flies and mosquitoes. Suggest remedies. 



REFERENCES 



Civic Biology Hodge and Dawson 



Applied Biology Bigelow 



Civics and Health Allen 



Birds in Their Relation to Man Weed and Dearborn 



