4 
INTRODUCTION 
The cocoanut has a buoyant husk that causes it to float 
in the currents of the ocean perhaps a hundred miles away 
till the waves carry it up on the shore, where it grows into a 
cocoanut tree. Some plants, like the wild geranium, hold 
the seed by a spring that throws the seed several feet, if it 
is touched. These are all adaptations that plants employ in 
making their kind grow. 
Animals and plants have come to occupy places in various 
parts of the earth because they have become fitted or adapted 
to the varying conditions. The main adaptations that have 
to do with the individual are: (1) those that assist in food 
getting, such as the cutting teeth of the squirrel or the sharp 
curved beak of the hawk or eagle (see Figure 99); (2) those 
that aid in self-protection, such as the rapid running of the 
fox or the color of a moth (see Figure 31); and (3) those that 
have to do with their surroundings, such as the fish, which is 
provided with fins for use in moving through the water, or 
the bird that has wings to fly through the air. 
Then there are adaptations that have to do with rivalry 
and the welfare of the young. Among the males of sea lions 
there is great rivalry which ends in the survival of the fiercest 
and strongest and death to the smallest and weakest. These 
contests among the males assure the young of sturdy par¬ 
entage. Tusks, horns, and biting teeth are some of the adap¬ 
tations. Certain fish, most birds, and some insects build 
nests where the young are cared for and given added pro¬ 
tection. The building of nests, together with the behavior 
of the adults during this time, are adaptations for the care of 
the young. 
If we inquire more critically into the way plants and ani¬ 
mals live, we shall see that they have in common other 
features besides adaptations. These are sometimes described 
as the fundamental functions of all living things. We shall 
need to know these before beginning the study of animals 
and plants. These fundamental functions are motion, 
