Natural Selection; Origin of Species - 551 



TEST QUESTIONS 



1. Calculate the number of offspring that would 

 be derived from a single pair of cats in ten 

 generations, assuming that the average num- 

 ber of kittens produced in each generation 

 were four and that all the offspring were to 

 survive and reproduce. Plot the theoretical 

 growth curve of this population of cats. 



2. A certain troutless pool, in which the food 

 supply can sustain no more than 100,000 

 trout, is seeded with 5 pairs of fingerlings. 

 Assuming that each pair produced 100 off- 

 spring annually, what percentage of the off- 

 spring can survive: (a) in the first year; (b) 

 in the second year; (c) in the third year; (d) 

 in each succeeding year. 



3. Predict ten factors in the inanimate envi- 

 ronment that might exert a selective action 

 upon the population of trout in the forego- 

 ing pool, and explain the type of variation 

 that would be probably favored by each of 

 the given factors. 



4. Consider Question 3 in terms of several pos- 

 sible factors in the animate environment of 

 the pool. 



5. To what extent does Question 3 illustrate: 

 (a) the "struggle for existence"; (b) the "sur- 

 vival of the fittest"; (c) natural selection 

 generally? 



6. Point out the essential similarities and differ- 

 ences between natural and artificial selection. 



7. Differentiate between external and internal 

 adaptations. 



8. Explain how the external adaptations of fish 

 generally equip these animals for life in the 

 aquatic environment. 



9. Explain how the external adaptations of a 

 particular species of fish may equip it for life 

 in a particular kind of aquatic environment 

 (for example, in a particular pool). 



10. In terms of some particular animal explain 



14. 



15. 



16. 



17. 



how some essential internal adaptation may 

 be responsible for perpetuating some neutral 

 or disadvantageous characteristics in the spe- 

 cies. 



To what extent has the environment of the 

 different areas of the earth (for example, 

 New York State) undergone drastic change 

 during the ages of prehistoric time? 

 In general, how is a species affected in num- 

 ber, diversity of variation, and area of habi- 

 tation: (a) during periods when the environ- 

 ment is especially favorable; and (b) during 

 periods when the environment is especially 

 unfavorable? Explain. 



Explain why isolation is a very important 

 factor in determining the origin of new spe- 

 cies. Explain several ways in which two or 

 more varieties of a species may become iso- 

 lated from each other. 



How may isolation from competitors affect 

 the perpetuation of a given species (for ex- 

 ample, the various monotremes and marsu- 

 pials [p. 673] of Australia)? 

 Differentiate between genetic variations and 

 environmental variations (modifications). Cite 

 five examples, to illustrate how a given ani- 

 mal (for example, man) and a given plant 

 (for example, a fruit tree) are susceptible to 

 the modifying influence of environmental 

 factors. 



Summarize the evidence that strongly sup- 

 ports the view that environmental modifica- 

 tions are noninheritable (choose at least two 

 specific examples). 



Carefully explain the Lamarckian concepts 

 of the mechanism of evolutionary change. 

 What has been the basis for discarding these 

 concepts? 



Carefully summarize the modern concepts as 

 to the mechanism of evolutionary change. 



FURTHER READINGS 



1. The Origin of Species, by Charles Darwin; 

 London, 1859. 



2. The Scientific Basis of Evolution, by T. H. 

 Morgan; New York. 1935. 



3. What Evolution Is, by G. H. Parker; Cam- 

 bridge (Mass.), 1925. 



4. The Causes of Evolution, by J. B. S. Hal- 

 dane; New York, 1932. 



7. 



Biochemical Evolution, by M. Florkin; New 



York, 1949. 



Genetics and the Origin of Species, by T. 



Dobzhansky; New York, 1951. 



The Material Basis of Evolution, by R. Gold- 



schmidt; New Haven, 1940. 



