THE PYRAMID OF LIFE
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THE PYRAMID OF LIFE
Plants are the basic source of food for other living-beings. Nature is organised rather like a pyramid. Each level represents a different step in the food chain.
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INTRODUCTION
- The energy in the form of light determines the varied climates and conditions of those different ecosystems in which an enormous variety of living-beings live.
- The Sun’s action and the different existing ecosystems.
- Plants and photosynthesis.
PHOTOSYNTHESIS
- Function of the chlorofil.
- Plants transform carbohydrates into more complex sugars, proteins and fats.
- Oxygen becomes a waste-product through the process of photosynthesis.
- With the exception of a few bacteria, plants are the only living-beings which can synthesize organic compounds from inorganic substances.
- Between 50 and 90% of all photosynthesis on Earth is carried out in the seas.
- Fitoplancton.
THE FOOD CHAIN
- Different steps or trophic levels: plants, primary consumers, secondary consumers, tertiary consumers, scavengers.
- As a general rule, as we move up the pyramid, we find that the size of the individual animals increases and their number dwindles.
- As we ascend upwards from the pyramid base, approximately 90% of the energy involved is lost betwen one step of the pyramid and the next.
- Examples of the lost energy in different species.
- Atoms and molecules do not disappear, but move cyclically from one organism and substance to others.
- Cyclical motion of water, oxygen, phosphor, sulphor and carbon.
- Coal, petroleum, and gas natural.
MAN
- Exploitation of the food chain.
- Farming and livestock raising.
- Mankind’s growth-rate.
- Deforestation. Realese of Carbon dioxide into the air. The Greenhouse effect.
SUMMARY |
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