Green Plants

090329tgt_dsc0072sAlmost everyone knows that animals breath in oxygen and breath out carbon dioxide, and the reverse is true of plants. That makes it sound as though the plants actually need us in order to breath. They don’t, because they can also “breath out” carbon dioxide as they do the work of staying alive; but we need them because we need oxygen. Before there were plants on earth the atmosphere did not have oxygen. Also because we need to get rid of the extra carbon dioxide in the atmosphere. The trick to all of life is balance, and this is one example of how the ecosystem keeps its balance so it can stay alive.

A while ago, talking about energy, I said there is high-level energy and low-level energy (and stages between) and that energy can go from high to low. However, it can not go from low to high level. Light is high energy, chemical energy is medium energy and heat is low energy. The genius of plants is that they can take high level energy (light from the sun) and use it to do the work of making medium level chemical energy (food). And then they can use the chemical energy (food) to do the work of staying alive.

I’ll say that again. The plant takes the energy of sunlight and uses it to make the major molecules of life. You may have heard on Star Trek (or was that before your time?) that carbon compounds are indicators of life. They don’t make themselves. The plant makes them, using energy from the sun. Even though every kind of cell is different, all cells are made up of carbon compounds: carbohydrates, lipids, proteins, DNA and other things. Carbohydrates are sugars and also the wood and cellulose the tree is made of. Lipids are fats. Proteins and DNA everyone has heard about on TV. The bottom line is this: the plant uses a source of high energy from the sun to make the molecules of life. The molecules contain chemical energy. The plant can then use the molecules and the chemical energy to do the work of keeping its cells alive.

carbondioxidelfAnd then of course, we do the same. We eat the plant and use the molecules to build our cells and the chemical energy to do the work of keeping our own cells alive. Animals can not live unless they have plants or other animals to eat because we can not use the energy of light to make carbon compounds. This will not be a surprise to you. The more interesting part is what happens to the chemical energy that the plants have stored in their tissues.

The first possibility is that the plant might die and become fossilized and turned into oil or coal or natural gas. Imagine how many plants and animals were fossilized millions of years ago. Now we mine the oil or coal or gas, because they are carbon compounds that are a rich source of the chemical energy the plants have captured from the sun, and they burn. We burn these to do the work of driving the car, heating the house, burning the light bulbs and running the factories.

Burning is the process of releasing the energy from a carbon compound. Oxygen is required for burning; that’s why we breath it in. Oxygen + carbon compound releases energy and carbon dioxide. Carbon dioxide is a waste product of burning. That’s why we (and the car) must get rid of it.

In the car, this burn is controlled and the energy that is released is used to do the work of firing the pistons.

In our bodies, in every cell, the burn is controlled and the energy that is released is used to do the work of sustaining our lives.

And all this energy comes from plants and only from plants because the only kind of energy we can use in our bodies is chemical energy.

If we use up all the oil and gas and coal that were made millions of years ago, we could of course burn wood. In very poor parts of the world people are forced to burn up all the trees — to use them for the same things that we use coal and oil and gas. In other poor parts of the world people are cutting down the forests, just as we cut down vast portions of the North American forests, to plant food for cows to eat. Or for us to eat. If we keep doing this, we will run out of trees to burn. We will run out of oil and coal and gas in any case. Sooner than later.

Before that time comes, many people believe we should try to find some way to use the energy from the sun directly, bypassing the green plant. We could MAKE food, but it would require more energy to make it than we would get back. And where would we get the energy? So that is not practical. We need to find a source of chemical energy that we can not cut down, burn up or use up. So that’s the fuss about sustainable energy.

090331_dsc0106sAnd converting light energy to chemical energy is not the only thing plants do for us. Remember where we started. Plants also “breathe in” carbon dioxide. That’s how they make carbon compounds in the first place. Plants can do the reverse process of burning. They use the energy of the sun to make carbon compounds. They take the carbon right out of the air, where it is cycling around and around through the ecosystem. They use light energy from the sun to make the big carbon compounds from the little carbon dioxide molecule (and other molecules that are also cycling around the ecosystem). At the same time the plant converts high-energy light from the sun into chemical energy that is stored in the large carbon compounds the plant is making. The problem here is that the carbon cycles around the ecosystem and has to be got rid of from atmosphere. The other problem is that ENERGY does not cycle around the ecosystem. It comes in as high energy. We use it to stay alive. Poof it is gone away in the form of heat and we can not make more chemical energy.

So we are back full circle. The people (and the cars and factories and power plants and all that) are eating the carbon compounds and using up the chemical energy that is stored in them — and at the same time we are breathing out carbon dioxide because it is a poison to us. The plants breath in the carbon dioxide and breath out oxygen that we require to burn the carbon compounds in our bodies.

Carbon dioxide is released into the air from all the burning in machines and in our own bodies, and carbon dioxide is a waste product that causes global warming.

What will happen as we continue to destroy the trees and other plants and burn them up in our machines and in our bodies? The more machines and the more people, the more carbon dioxide. The fewer trees and other plants — also the more carbon dioxide. And less oxygen and less energy available in the form of chemical energy. Energy is all around us, yes, but the energy of life is chemical energy.

So that’s what people worry about, and it is completely logical that we should worry. This exchange system between plants and animals has created our ecosystem. It is based in natural laws of physics and biology that can not change. Therefore, if we want human kind to survive, we need to understand the natural laws that keep us alive — and behave accordingly.

The point is not to rush out and get more excited than the media over who is wearing what color this year (green is good). The point is, as T.D.Jakes has said: “You can not change what you do not confront.” Of course he is right, but “Confront?” Why do we always think we have to fight with each other and with life? Life is about balance; without balance there is no life. Our success will come when we stop confronting each other about things that none of us can control, and begin the discussion. The point is to talk about it.

Among all the millions of people on earth, I think if we start to talk together -here is an example – about our problems we might actually come up with solutions that work within the natural laws of the ecosystem, and I think that’s better than waiting around for Exxon or Fox News to save us from them.  I think that would be a long wait.

Do you know of any other examples, in addition to simple-green-frugal, the link above here, of people talking together about down-to-earth factual biological reality?