9 6 
THE} STORY OR THE OAK TRE}E} 
Here again we see another strong link in Nature’s Web 
of Life. It was the plants which prepared the dry land 
for animals. The barren land of those ancient times af¬ 
forded no food or shelter for animals; not until plants 
appeared could the creatures crawl out of the sea and 
carry on their great adventure of life upon the shore. 
And besides food and shelter and places to hide, the 
plants gave one more thing to the animals; perhaps you 
can guess what this was if you recall Chapter I, on “The 
Leaf.” Can you remember that magic fluid in the 
leaf, called “chlorophyll?” And do you remember the 
tree-breathing, or transpiration, by which the tree breathes 
in carbon dioxide and breathes out oxygen? Of course 
you do, and you remember also that oxygen in the air 
is necessary to keep the firels of life burning in us and in 
all animals. So plants gave oxygen to the animals. 
In the long run, then, all animals depend on plants, 
and all plants depend upon the soil. 
The soil is not dead. Although it looks as lifeless as 
a stone, it is filled with living creatures, insects, earth¬ 
worms, and tiny creatures called “bacteria” which are 
busy all day long making the soil fertile that your gar¬ 
dens may grow. These bacteria are as small as our 
old friend the ameba, but they are hard workers. When 
in autumn the leaves fall from the trees, when the 
green plants die, they disappear, but they are not wasted. 
