6 ANIMAL FORMS 
its death should leave offspring to take the place of the 
parent when it falls from the ranks. This is effected in 
various ways. In some of the simpler animals the body 
may divide into two equal parts, each of which becomes a 
complete individual. In other cases the animal detaches 
a relatively small portion of its body, much as a gardener 
cuts a slip from a plant, and this likewise develops into a 
new organism. In the greater number of animals, very 
clearly illustrated by the birds, eggs are produced which 
under favorable conditions develop into an organism resem- 
bling the parents. 
6. Summary.— Animals are thus seen to lead active, busy 
lives, collecting food, avoiding enemies, and producing and 
and caring for their young. While the activities of all 
animals are directed to their own preservation and to the 
multiplication of their kind, these processes are carried on 
in the most diverse ways. The manner in which an organ 
or an organism is made, and the method by which it does 
its work, are mutually dependent one on the other. As 
there is an enormous number of species of animals, each 
differently constructed, there is, accordingly, a very great 
variety of habits. As we shall see, the lower forms are 
remarkably simple in their construction, and their mode of 
existence is correspondingly simple. In the higher types 
a much greater complexity exists, and their activities are 
more varied and are characterized by a high degree of elabo- 
ration. In every case, the animal, whether high or low, is 
fitted for some particular haunt, where it may perform its 
work in its own special way and may lead a successful life 
of its own characteristic type. 
