Last week, Andy answered a question about parasites, those plants and animals that live on their neighbors and give nothing in return. The idea makes us think that we all take things from Mother Nature and give nothing in return. We eat plants and animals, we use water and breathe the air and we give, it seems, little or nothing in return for these things. But this is not true, for indirectly we help Mother Nature in many ways.

Some people like to trot out the idea that we humans are parasites, living for free on the world of plants. True, the plants provide our oxygen and everything we eat. But they need carbon dioxide to make their food and grow, This is the waste gas we and most animals breathe out and more is added to the air by our fires and factories.

Plants use our throw away carbon dioxide and we use their throw away oxygen. Both gain from this fair trade and it is the kind of give and¬ take which goes on throughout the world of Nature. This is the study of ecology and the more we learn about it, the more we see how much of this trading goes on among Nature's children.

However, there is something upon which all life depends and for which no plant or animal can give anything in return. This free gift is the radiant light of the sun which beams down upon the earth. Without it all life would freeze to a standstill. Even if we could see, and keep ourselves warm, we would soon perish from lack of food and oxygen,

For plants use the energy from sunlight to make their food and grow, They use sunlight to produce our oxygen and every item of our daily diet. We eat plants and we eat meat and dairy products which come from animals that eat plants.

The energy of sunlight is used to make these foods and when we digest them, this energy is released and used by our bodies. So we can say that our food is stored sunlight, or we can be more poetic and say that we live on bottled sunshine. All the plants and animals, Nature’s children, trade among themselves and depend upon give and take with each other. But directly or indirectly, every living thing depends upon energy from the radiant light which Old Father Sun pours down upon our world.

In the study of ecology we see how organic materials, such as decaying leaves, bodies and animal wastes, enrich the soil. This provides chemicals which plants also need. Almost every plant or animal trades all kinds of things with its neighbors   but every one of them needs the sunshine, which is spread around for free.