Topic 4 Cycles of Life

4.1 – The Carbon/Oxygen Cycle 4.2 – The Nitrogen Cycle 4.3 – Phosphorus and ___ Cycle Cycles of Life All life requires nutrients and nutrients are continually recycled … if they were not, they would become used up and life on Earth would cease to exist.

4.1 – The Carbon/Oxygen Cycle The Carbon/Oxygen Cycle is interconnected and involves three major processes and one minor process: 1. Photosynthesis 2. Respiration 3. Combustion 4. Decomposition

1. Photosynthesis Green plants/trees take in carbon dioxide and water using the chlorophyll in their leaves and energy from the sun they release oxygen , sugar and water vapor .

1. Photosynthesis

1. Photosynthesis Formula:

2. Respiration Animals take in simple sugars and oxygen and release carbon dioxide, water and energy

2. Respiration Formula:

3. Combustion This is the process of burning. When combustion occurs CO 2 is released into the atmosphere. Natural combustion includes volcanic eruptions, however most pollution problems occur because cars and factories release CO 2 by their burning fossil fuels.

3. Combustion Fossil Fuels: Coal, Gas and Oil

3. Combustion During the Carboniferous Period (300 mya) large amounts carbon (in the tissue of plant matter) was trapped underground. Because of lack of oxygen and tremendous pressure, the plant matter was compressed into fossil fuels.

3. Combustion Combustion due to fossil fuels over contributes to the carbon cycle, which is accelerating the negative effects of global warming.

4. Decomposition When an animal or plant dies all the carbon , oxygen , nitrogen, water, calcium etc. return to the soil and air during decomposition. Certain insects, fungi and bacteria aid in the decomposition process and are called decomposers .

4. Decomposition

Putting It All Together …

PHOTOSYNTHESIS

RESPIRATION

COMBUSTION

DECOMPOSITION

Topic 4.1 Assignment 1. Carbon/Oxygen Cycle Notes 2. Read page 1-4. 3. Complete Questions #