Ecology and Evolution - 591 



8. Differentiate between: (a) a vaccine and an 

 antiserum; (b\ an antigen and an antibody; 

 (c) antibiotics and other chcmotherapeutic 

 agents. 



9. Specify three different disease vectors. Ex- 

 plain the relation between a disease vector 

 and an intermediary host. 



10. Discuss how each of the following has been 



important as a factor in natural selection: 

 (a) temperature; (b) light; (c) gravity; (d) 

 pressure; (e) the water supply. 



11. What are xerophytes, mesophytes, and hydro- 

 phytes? In each case specify some of the dis- 

 tinctive adaptations. 



12. What is an ecosystem? Discuss the economy 

 of any one. 



FURTHER READINGS 



1. Fundamentals of Ecology, by E. P. Odum; 3. Principles of Animal Ecology, by W. C. Allee 

 Philadelphia, 1959. and others; Philadelphia. 1949. 



2. Elements of Ecology, by G. L. Clarke; New 4. Ecology, by E. P. Odum; New York, 1963. 

 York, 1954. 



