Land Environments

This is the last part of the Land environments series. This part is more of a basic chemistry lesson that goes along with the smallest elements that are found in the various environments mentioned.

We can safely say that nuclear reactions do not occur in living things. Under ordinary circumstances and conditions chemical laboratories, nuclear reactions do not occur. In other words you cannot destroy the quantity of iron that was in the nail. All you can do is convert the pure iron to other forms of iron and combine it with other substances, as if you take the iron nail and put it in an acid that will dissolve the iron. This by scientists is called conservation of matter--In ordinary chemical change, matter is neither created or destroyed.

(Now on the blackboard write the word 'Greek'- 'home'- 'oikos'). This is the start of defining the term 'ecosystem' the ecologists called a system that supplies living things with all their needs for life.)

A pond is an ecosystem for a fish.

A forest is an ecosystem for a deer.

The whole world is an ecosystem for man.

Man is interdependent with all living things - Ask students what does 'interdependent' means.

Now for some basic chemisty.

Combining Atoms

All atoms of any element present on earth today were probably in existence millions of years and still be here millions and millions of years from now, but not nuclear change.

By recombining the atoms of elements different compounds can be made.

Recombining of elements

H- hydrogen O- oxygen C- carbon

Certain proportions are sugar glucose - C6 H12 O6

There are still different combinations of sugars. There are ways to combine them and get starches; still again there is a cellulose formed you put wood to a match. (Example- carbon atoms in cellulose combine with the oxygen and hydrogen from the air to produce water (H2O) and carbon dioxide (CO2) if burning is not complete of the match some of the carbon remains.

In this kind of chemical change matter is not lost and matter is not created.

Change the proportions of these attachments to the atoms you get fats.

Remove the oxygen - recombine the hydrogen and carbon you get waxes and gasoline. Atoms themselves not changed and not destroyed.

Borrowed atoms

Our bodies are made up of water, fats, proteins, sugars and other compounds.

These compounds are made up largely of carbon, hydrogen, oxygen, and nitrogen- smaller amounts of copper, calcium, iron, sulfur, sodium, chlorine, magnesium, and phosphorous.

Where does our bodies get these substances?

We get them from the food we eat, the liguids we drink, and the air we breathe. Most come from the food we eat. How do these substances get into the food we eat? The cow (beef) we eat gets those substances from the plants they eat that grow from the air they breathe, and water they drink, too.

How do plants get the atoms? Plants take in water (H2O) from the ground-along with the water and takes in a variety of minerals containing elements such as iron, phosphorous and calcium. Nitrogen also from compounds dissolved in the ground water taking in carbon in the form of carbon dioxide from the air?

Part One- Plants and animals do not live forever and those atoms cannot be destroyed.

Part Two- When plants and animals die, their bodies are decayed by bacteria- 'decaying'- (write on blackboard) means that the atoms are released in different and simplier compounds. These different compounds are able to be used by other plants and animals.

Part Three- Plants and animals are eaten by other animals and the atoms are recombined within these new animal bodies and are used over again.

Actual fact: that the plants and animals of the world keep reusing the same old atoms.

They are indestructible over and over again in a wide variety of compounds that living things need and make.

Atoms that are in our bodies now were used by plants and animals over the years. These atoms our bodies are using were once part of a rose petal; tall pine trees; or even an one-celled organism.

The Conservation of Energy

Energy can no more be created nor destroyed than can matter. Energy cannot be destroyed. It can be changed to different kinds of energy.

light energy-----thermal energy-----mechanical energy

Thermal energy- 'heat' energy

Mechanical energy- electrical energy

You can change energy, but cannot be destroyed.

Useful purposes- a considerable amount of energy is lost as heat into the atmosphere and elsewhere.

Chemical energy to make energy of motion or thermal energy we need this to survive. We get this energy from the foods we eat. Chemical energy is locked up in these foods. The chemical energy is really trapped energy of the sun.

Green plants from light energy from the sun are able to change water and carbon dioxide into sugars and then these sugars may be changed into starches, fats, and proteins. 'The Sun's energy converted to chemical energy is still locked in these foods. Animals may then eat plants. When we eat the animals we also eat these elements and compounds and their stored energy.

When we eat the plants (vegetables) sugars and starches- also energy stored in the molecules. We need these for our body functions as moving, keeping warm and thinking.

Concept of conservation of energy is a little different from conservation of matter.

'The atoms of our bodies will someday be released.' Be available to other living things. Energy you are now using will not be available to other living things. Our bodies are giving off heat - not lost- immediately warming your surroundings slightly and will eventually radiate out into space and be gone from earth.'

Energy must be constantly renewed and can be accomplished by green plants trapping more sunlight to be changed into chemical energy for all living things. The world ecosystem (What is an ecosystem?) in it living things are independent. (What is interdependent?) with each other and with the environment.

Man, is everywhere for the world ecosystem.

REMEMBER:

'In chemical change, matter is neither created nor destroyed.

Energy maybe transformed from one form to another, but it is neither created or destroyed.

The total amount of matter and energy is conserved.

Reference of this lecture and previous lecture notes.

Life A Biological Science Chapter 3 Land Environments Brandwein Edition