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carnivores may in turn be eaten by a succession of other carnivores, the tertiary carnivores. A simple example of food chain is:'
Sun—Cabbage—Cabbage white caterpillar—thrush-kestrel.
In reality, the relationship is seldom so simple. An animal would consume several kinds of food and in turn becomes the food of several ohers. Thus the food chains are intertwined into a web and we speak of Food Webs rather than of chains.?
Thus matter is cycled and so is never exhausted; energy is always lost and must be replenished.?
So now we know that the dead bodies of the mobile living organisms, from those with two sense-organs to those with five sense-organs which include MAN are recycled and consumed by plants to begin the new cycle.
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1. Flow of Energy: Though nothing is lost from the substance of the dead bodies, energy is lost totally and for ever.
The maximum quantity of energy received by the earth from the sun is 7500 k. calories (the average being about 3000 k.calories) per square meter per day. Of this only 1% to 5% is converted to food during primary production. Of the average of 3000 only 1500 k. cals are used by green plants and from this only 15 k. cals worth of new growth is produced. Thus, during the first step the reduction factor is 100. Of the 15 k.cals available to the primary consumers, they can use only 1.5 k. cals for their growth. Out of this the secondary consumers' share is only 0.15 k. cals while the tertiary's is very meager indeed. 2. Food chain in the Sea: Primary production starts with the phytoplankton, the minute algae an flagellates of the surface layers of the sea. The primary consumers are zooplanktons, considered to be the insects of the sea. Krills, Arrow Worms etc The secondary consumers are smaller fishes and squids which are preyed upon by larger and larger consumers like Medisae, tunas, dolphins, sword fish, toothed whales and the greatest of all the Baleen Whale. (It is both a vegetarian as well as carnivore).
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