Question

Why do most food chains consist of four steps? 

Answer 1

Well, the only way to explain this is to think mathematically. At the bottom level are plants. Let's say they absorb about 10% of the Sun's energy to convert to food. Then animals that eat the plants get only 10% of that energy. Carnivores, the next level, get only 10% of that (which is 0.1% of the energy from the Sun). As you can see, the higher an organism's level in the food chain, the fewer can exist. If you had 10 lions and 10 deer, all the deer would be killed and eaten and the lions would starve before the deer could have any babies. This means that if you go beyond about 4 levels, it is unsustainable to any organisms.

Answer 2

Most of the food chains have only 4 steps because:-
1)If there is a long food chain then less energy transfer takes place.
2)This lead to the extinction of top carnivore.
3)this create ecological imbalance.
4)So many food chains consist of 4 steps.