CHAPTER EIGHT. 

 RELATIONS OF PARENTS AND OFFSPRING 



1. Parental Sacrifice. In all these kinds of reproduction 

 you have studied you see that to form the offspring is a 

 drain on the parent. A part of the parent's body goes 

 directly to form each of the young, or some special 

 growth takes place from the parent which forms the 

 young, and in doing so uses up food materials that might 

 have gone to strengthen the parent instead. This 

 sacrifice is the one unvarying fact in all the varying 

 methods of reproduction. 



2. The Species and the Individual. In such plants and 

 animals as we have been studying, all that an individual 

 can do for the species is to reproduce offspring. This is 

 the very simplest and easiest form in which to introduce 

 individual sacrifice for the race. The species flourishes in 

 proportion as individuals first build themselves up, and 

 then reverse matters and exhaust themselves in putting 

 offspring on the way to success. 



3. The Degrees of the Sacrifice. While all plants and 

 animals seem driven by their nature to make this sacrifice, 

 there seems to be a distinct tendency, as we go up the 

 scale, to make the sacrifice as light as possible and still 

 do the work. At least we find it very much lighter in 

 some organisms than in others. For example, we saw in 

 the bacteria and some other simple forms that the parent 

 was at once completely destroyed in forming the two 

 offspring. In the yeast, on the contrary, the new cells 



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