A Matter of Life and Death

“… death, a necessary end, will come when it will come.”

-Julius Caesar

The Chemistry of Life

• Decomposition and growth are evidence of the recycling of matter that life depends on.

• Every organism is made up of combinations of chemical elements, such as carbon (C), hydrogen (H), oxygen (O), and nitrogen (N).

• Organic substances always contain atoms of carbon and hydrogen.

• Proteins, sugars and fats are important organic chemicals that make up your body.

• Matter that does not contain carbon and hydrogen are called inorganic.

• Carbon dioxide, water and ammonia are inorganic.

Nutrient Cycles

• The chemical elements that are used by organisms to build and operate their bodies are called nutrients.

• The movement of nutrients through the environment (soil, water, air, other organisms) are called nutrient cycles.

• The Earth is a closed system.

• A closed system is an environment in which substances do not enter or leave.

• Therefore, the Earth has had all the nutrients it will every have!

Decomposers

• Decomposers break down organic matter in dead bodies and feces into small, inorganic molecules. These small molecules can then pass into soil or water to be recycled.

• Bacteria, fungi and mould are examples of decomposers.

• To sustain life over millions of years, nutrients are constantly recycled.

• When an organism dies, the materials in its body are returned to the environment where they can be used by other living things.

• Without death and decomposition, these materials or chemicals would eventually be used up.