What is required for life to be possible? The birth and existence of life requires:

• water in liquid form
• elements that render life possible, such as carbon, hydrogen, nitrogen, oxygen and phosphorous
• a source of energy, such as the Sun.

There can be no life without energy. Energy is used to construct complex chemical compounds, to move, and to make different things happen. The life on our planet receives most of its energy from the Sun. 

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Plants need water and sunlight, among other things. Animals require water as well as energy produced by plants.

Plants, algae and some bacteria are capable of photosynthesis, which means that they can make use of light energy from the Sun to produce chemical energy, stored in chemical compounds. All other organisms are dependent on the chemical energy produced by plants. 

The solar energy bound by green plants and other producers moves through the food chain and is used by consumers, such as herbivores and predators.

Life on earth is organic, which means that it is based on different carbon compounds. Carbon is an element that can form a variety of different chains and wheels. 

The molecules that are significant for living organisms, such as carbohydrates, fats, and proteins, are comprised of carbon chains that have elements such as hydrogen, nitrogen and oxygen attached to them. Life as we know it also requires other elements, such as phosphorous, potassium, calcium, magnesium and iron. 


Solar energy is bound by plants and transferred to herbivores and other consumers.