JoLY — The Abundance of Life. 



83 



of reproduction might be expected to have an important influence 

 in determining the particular periodicity of the organism; and 

 were we to depict in the last diagram, on the same time-scale as 

 Man, the vibrations of the smaller living things, we would see 

 but a straight line (save for secular variations in activity) repre- 

 senting the progress of the species in time. The tiny thrills of its 

 units lost in comparison with the yet brief period of man. 



The direct influence of the rate of reproduction on the duration 

 of the individual is, indeed, very probably revealed in the fact that 



10 70 100 Time. 



Fig.^. Imaginary Life- Waves of Man, (i);Dog, (2);&'Tortoise, (j). 



short-lived animals most generally reproduce themselves rapidly 

 and in great abundance, and vice versa. In many cases where this 

 appears contradicted, it will be found that the young are exposed 

 to such dangers that but few survive {e.g. tortoises and turtles, &o.), 

 and so the rate of reproduction is virtually slow. Most insects are 

 rapid breeders, and are short-lived. Many birds, as eagles, are 

 slow breeders, and long lived. Elephants are very long-lived, and 



