1. A Matter of Life and Death “… death, a necessary end, will come when it will come.” -Julius Caesar

2. 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).

3. 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.

4. 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.

5. 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!

6. 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.

7. 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.