PARENTS AND OFFSPRING , 47 



are correspondingly increased. It is more expensive to 

 produce large offspring, but they are nearer their goal. 

 With a given outlay many more of the small offspring can 

 be produced, but they are not so sure. Each method has 

 its advantages. 



7. The Tendency to Diminish the Size of Offspring. As 

 we come up in the plant and animal kingdoms, we find that 

 the size of that part of the parent which enters into each 

 of the offspring is decreased. We find further that less 

 and less of the substance of the parent is given up to 

 making offspring, and that more of the parental body is 

 left to live and reproduce again and again through a 

 considerable period. Thus, instead of parents dying in 

 producing the offspring, the parents may live along side 

 by side with them for a considerable period. By this 

 means the parent may produce even more offspring than 

 if it gave all its substance to offspring at the outset; and it 

 may distribute them through a better period of time. 



8. Combination of Methods in One Parent. There are 

 some organisms that use several methods of reproduction. 

 As we have seen, one of the molds produces many small 

 spores, and at the same time, or a little later, it sends out 

 a stolon or two and thus starts a new plant as vigorous 

 as the first. By the first method it gets the advantage of 

 numbers and distribution; by the second it gets more 

 quickly matured offspring, but not so many of them. This 

 combination is a most successful one to insure the 

 adjustment of the plant to its conditions of living. It is 

 found in many plants and animals. 



