EXERCISE 127 



In all except a few species of small animals, reproduction- is brought about by the fusion of a sperm 

 cell with an egg cell. But there is great variation in the number of individuals produced and in the 

 relation between parent and offspring after the discharge of the gametes. 



From prepared specimens, models, and charts gather the information needed for completing the 

 following table, giving the name of the type studied in each case : 



Questions. 1. What relation is there between the number of gametes discharged and the number 

 of fertilized eggs that reach maturity ? 



2. What connection is there between the number of individuals produced and the amount of aid 

 each gets from the parents ? 



3. Of what does parental care consist ? Of what value is it to (a) the individual and to (b) the 

 species ? 



4. What connection is there between the amount of care the individual receives and his chances 

 of maturing? 



5. How far is your last statement true of human beings ? 



[138] 



