CHAPTER LXIII 

 INFANCY AND PARENTAL CARE 



384. Infancy in lower plants. Among the one-celled plants 

 or animals each cell resulting from a cell division begins to 

 shift for itself immediately, as soon as it comes into existence 

 as a distinct cell. The simplest organisms of any series are 

 detached from their parents and shift for themselves early in 

 life. As we go up the scale we find that more and more do 

 the parents provide for the offspring in the way of food or 

 protection or both. 



Among the seaweeds, like bladder wrack and many other 

 species, the gametes are thrown into the water, where thousands 

 are destroyed for every pair that fertilize and establish a new 

 individual. 



In the mosses and ferns the female gametes are retained 

 within the body of the parent plant until after fertilization, and 

 until the new plant has been well started. In the mosses 

 the new plant gets nearly all of its nourishment from the 

 parent plant. 



385. Infancy in seed plants. When we come to the highest 

 plants, the adaptation of structure and behavior to the apparent 

 advantage of the species is still greater. The spores are pro- 

 duced in comparatively small numbers and the gametes in still 

 smaller numbers. The fertilized egg is completely protected by 

 rather elaborate structures, and the young plant develops within 

 the body of the parent until it is fairly well along — in most 

 species until the root, stem, and leaves are quite distinguishable. 

 In addition to the nourishment and protection, the parent also 

 supplies a quantity of food that is available after the baby plant 

 is separated from the parent. And in most species we find a 



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